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13: 10-modul: Genlar va xromosomalar - Biologiya

13: 10-modul: Genlar va xromosomalar - Biologiya


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13: 10 -modul: Genlar va xromosomalar

Xromosomika: genomlar va xromosomalar orasidagi bo'shliqni to'ldirish

So'nggi paytlarda DNK sekansirovkalash texnologiyasidagi yutuqlar sekomlangan genomlar sonining tez o'sishiga imkon bermoqda. Ammo, genom biologiyasidagi ko'plab asosiy savollar javobsiz qolmoqda, chunki ketma -ketlikdagi ma'lumotlar genomning xromosomalarga qanday ajratilganligi, bu xromosomalarning hujayradagi o'rni va o'zaro ta'siri, xromosomalar va ularning o'zaro ta'siri qanday o'zgarishi haqida tushuncha bera olmaydi. atrof-muhit stimullariga javoban yoki vaqt o'tishi bilan. DNK ketma-ketligi va xromosoma tuzilishi va funktsiyasi o'rtasidagi yaqin munosabatlar genom arxitekturasining genom plastisitesida o'ynaydigan rolini yanada to'liqroq tushunish uchun genomik va sitogenetik ma'lumotlarni birlashtirish zarurligini ta'kidlaydi. Biz "xromosomika" atamasini genomlar ketma-ketligi, sitogenetika va hujayra biologiyasini o'z ichiga olgan yondashuv sifatida qabul qilishni taklif qilamiz va xromosomikaning yangi kashfiyotlarga olib kelgan misollarini keltiring, masalan, evteriy sutemizuvchilarning jinsini aniqlovchi gen. Eng muhimi, biz kelajakka va xromosomika inqilobiga kirganimizda javob berilishi mumkin bo'lgan savollarga, masalan, turlanishdagi xromosomalarni qayta tashkil etishning roli va genomning tez rivojlanayotgan hududlari, masalan, sentromeralar, genom plastisitesida o'ynaydi. . Biroq, xromosomikaning to'liq salohiyatiga erishish uchun biz bir qator muammolarni hal qilishimiz kerak, xususan, sitogenetiklarning yangi avlodini tayyorlash va genomika, sitogenetika, hujayra biologiyasi va bioinformatikaning tadqiqot yo'nalishlari o'rtasida yaqinroq ittifoqqa sodiqlik. Ushbu qiyinchiliklarni bartaraf etish genom evolyutsiyasi va funktsiyasini tushunishda yangi kashfiyotlarga olib keladi.

Kalit so'zlar: tsentromer xromosomalarni qayta tuzish sitogenetika evolyutsiyasi genom biologiyasi genom plastiklik jinsiy xromosomalar.

Manfaatlar to'qnashuvi to'g'risidagi bayonot

Mualliflar hech qanday manfaatlar to'qnashuvini e'lon qilmaydilar.

Raqamlar

DNKni xromosomaga qaytarish. Ikki zanjirli DNK spiral atrofiga o'ralgan ...

Qo'shimcha yutuqlar orqali amalga oshirildi ...

Kashfiyotda birlashtirilgan sitogenetik va genomik ma'lumotlar orqali bosqichma -bosqich yutuqlar ...

Integrativ buzilish modeli, a…

Integrativ buzilish modeli, genom evolyutsiyasini o'rganish uchun ko'p qatlamli asos ...


Kinesin-13 oqsillari Kif2a, Kif2b va Kif2c/MCAK inson hujayralarida mitoz jarayonida alohida rollarga ega.

Inson genomida Kif2a, Kif2b va MCAK (Kif2c) deb nomlangan kinesin-13 oqsillarini kodlaydigan uchta noyob gen mavjud. Kif2a va MCAK mitozda hujjatlashtirilgan rollarga ega, ammo Kif2b funktsiyasi aniqlanmagan. Bu erda biz Kif2b madaniyatli hujayralarda juda past darajada ifodalanganligini va GFP-Kif2b asosan tsentrosomalar va o'rta tanalarda, balki shpindel mikronaychalarida va vaqtinchalik kinetokorlarda lokalizatsiya qilinishini ko'rsatamiz. Kif2b etishmovchiligi bo'lgan hujayralar monopolyar yoki tartibsiz shpindellarni yig'adi. Kif2b etishmaydigan hujayralardagi xromosomalar odatda kinetoxor-mikrotubulali birikmalarni ko'rsatadi, lekin nazorat hujayralariga nisbatan harakat tezligi taxminan 80% ga kamayadi. Ba'zi Kif2b etishmovchiligi bo'lgan hujayralar anafazaga urinishadi, ammo bo'linish jo'yaklari regressiyalanadi va sitokinez muvaffaqiyatsizlikka uchraydi. Kif2a etishmayotgan hujayralar singari, bipolyar shpindellar to'plami bir vaqtning o'zida MCAK yoki Nuf2 etishmasligi yoki past dozali nokodazol bilan davolash orqali Kif2b etishmayotgan hujayralarga tiklanishi mumkin. Biroq, Kif2b etishmayotgan hujayralar NuMA va HSETning qutbga yo'naltirilgan faoliyati buzilganida, ular bipolyar millarni yig'ib olishlari bilan ajralib turadi. Ushbu ma'lumotlar Kif2b funktsiyasi shpindel yig'ilishi va xromosoma harakati uchun zarurligini va Kif2a, Kif2b va MCAK ning mikrotubulali depolimeraza faolligi inson hujayralarida mitoz jarayonida alohida funktsiyalarni bajarishini ko'rsatadi.

Raqamlar

Madaniy hujayralarda Kif2b ifodasi.…

Madaniy hujayralardagi Kif2b ifodasi. (A) Transfektsiyalanmagan U2OS hujayralaridan jami hujayra ekstrakti…

GFP-Kif2b lokalizatsiyasi. (A) Inson ...

GFP-Kif2b lokalizatsiyasi. (A) GFP-Kif2b ni ifodalovchi inson U2OS hujayralari interfazada va…

Kif2b mil uchun juda muhim ...

Kif2b milning bipolyarligi uchun zarurdir. (A) ishlov berilmagan U2OS yoki U2OS hujayralari transfektsiya qilindi ...

Xromosoma tezligi bostiriladi ...

Kif2b etishmaydigan hujayralarda xromosoma tezligi bostiriladi. (A) U20S hujayralari davolandi ...

Kif2b etishmaydigan hujayralar barqaror kinetoxor hosil qiladi ...

Kif2b etishmovchiligi bo'lgan hujayralar barqaror kinetoxor mikrotubulalar biriktirmalarini hosil qiladi. U2OS hujayralari davolanmagan yoki…

Kif2b etishmasligida sitokinez buziladi ...

Kif2b etishmaydigan hujayralarda sitokinez buziladi. Kif2b nuqsonli hujayralarning DIC mikroskopi bilan ...

Kif2a, Kif2b va MCAKda…

Kif2a, Kif2b va MCAK mitoz jarayonida alohida funktsiyalarga ega. (A) Mitozlarning ulushi…

Kinesin-13 genlarini filogenetik taqqoslash.…

Kinesin-13 genlarini filogenetik taqqoslash. Kodlangan uchta kinesin-13 oqsilidan amino kislotalar ketma-ketligi ...


Natijalar va muhokama

FISH tahlili bilan to'qqizta PKC lokusining xromosomali nozik xaritasi

Genomik klonlar to'qqizta inson PKC izotiplari uchun cDNK zondlari yordamida inson genomik kutubxonalaridan yuqori qattiq gibridizatsiya sharoitida ajratilgan. Polimeraza zanjiri reaktsiyasi (PCR) bilan tasdiqlangan genomik PKC klonlari (har bir gen uchun beshtagacha klon) keyinchalik FISH yordamida PKC gen modulining inson xromosoma joylashuvini aniqlash uchun ishlatilgan. Floresanli dubletlar har bir opa -singil xromatidalaridagi metafazalarning aksariyatida 1a -rasmda ko'rsatilgan pozitsiyalarda kuzatilgan, bu to'qqizta aniq PKC genlarining kompozitsion karyotipini ko'rsatadi. Boshqa hech bir xromosoma joyida muhim lyuminestsent signallar ko'rsatilmagan (ma'lumotlar ko'rsatilmagan). Sakkiztagacha signal uzatuvchi xromosomalarning flüoresans intensivligi o'ta muhim yashil-qizil profilni yaratish uchun o'lchandi. Ushbu profil standart xromosoma ideogrammalarining o'lchamiga chiziqli interpolyatsiya qilingan bo'lib, flüoresan signallarni xromosoma bandiga ob'ektiv belgilash imkonini berdi. Metafaza odam xromosomalarida lyuminestsent nuqta taqsimotining diagramma ko'rinishi 1b -rasmda ko'rsatilgan.

FISH tomonidan to'qqizta inson PKC gen lokuslarining metafaza tarqalishiga xromosoma xaritasi. (a) FISH tomonidan tayinlangan to'qqiz xil PKC genining kompozitsion karyotipi (yashil rangda) inson metafazasi tarqalishiga (DAPI/PI tasmasi). PKC gen mahsuloti yorlig'i mos keladigan xromosomalar bandiga o'rtacha floresans cho'qqisining tayinlanishini ko'rsatadi. (b) Floresan dog'larning tarqalishini aks ettiruvchi ideogrammalar (ideogrammalar yonidagi vertikal chiziqlar bilan ko'rsatilgan). Har bir belgi bitta gibridlanish nuqtasining lokalizatsiyasini ifodalaydi n = to'plangan metafazalar soni.

Shunday qilib, mavjud ma'lumotlar to'plamini tasdiqlash va/yoki tuzatish uchun barcha a'zolarning xromosoma joylashuvi aniq xaritaga kiritildi. 1 -jadvaldan ko'rinib turibdiki, PKC ning to'qqiz a'zosidan beshta izotip - PKCa, b, δ, ζ va y - mavjud adabiyotlarda insonning individual xromosomalariga to'g'ri taqsimlanmagan [5,7,8,9,10, 11,12,13]. PKC genlari uchun xromosoma joylashuvimizni genom loyihasi topshiriqlari (HUGO) bilan taqqoslash natijalarimizni tasdiqladi, ammo bizning FISH batafsil tahlilimiz xaritaning yuqori aniqligini ta'minladi.

Xususan, X xromosomasiga (Xq21.3 [13] va HUGO, 1 -jadvalga qarang) PKCi gen lokusining qayd etilgan lokalizatsiyasi tasdiqlanmadi, chunki biz 3q26 da qo'shimcha FISH signalini aniqladik. Odam genomining qoralama ketma-ketligidan ajratib olingandan so'ng, PKCy ni o'z ichiga olgan Xq21.3 xromosomali DNK ketma-ketligi 3q26 da haqiqiy genga o'xshash qayta ishlangan psevdogen ekanligi aniqlandi. Ushbu PKCi Xq21.3 psevdojeni uzluksiz ochiq o'qish ramkasini (ORF) o'z ichiga oladi va retrotranspozitsiya orqali kelib chiqishiga mos keladigan intronlar yo'q. Qizig'i shundaki, u PKCi genlar ketma -ketligi bilan bir xil, to'xtash kodonidagi bitta nuqta mutatsiyasidan tashqari (2 -rasm), bu ORFni 27 ta aminokislotaga uzaytiradi. Shuning uchun PKCi Xq21.3 psevdojeni ifodalanishi mumkin. Ikkala bo'lajak PKCi mRNKsi juda yuqori identifikatsiya qilinganligi sababli, bu ehtimolni faqat soxta oqsilli mahsulotning 27 ta aminokislotalar ketma -ketligini aniqlash uchun mo'ljallangan antikor yordamida tekshirish mumkin edi va bunday antikor hali mavjud emas.

PKCi Xq21.3 psevdojenining aminokislotalar ketma-ketligi. Uzluksiz ORF qizil rangda. Yovvoyi tipdagi TGA to'xtash kodonini CGA ga qaytaradigan nuqta mutatsiyasi ko'k rangda ko'rsatilgan.

3q26 xromosomasida (va Xq21.3 psevdogenida) PKCi lokusidan tashqari, 12-xromosomaga (BAC KlonRP11-147C2) xaritada tuzilgan odam genomining loyihasida boshqa PKCi genomik ketma-ketligi topilgan. 12-xromosoma va 3-xromosoma PKCi genlarida intron joylashuvining mos kelishi ularning genomik tuzilishidagi mumkin bo'lgan eng yuqori homologiyani ko'rsatdi, masalan, 12-xromosoma PKCi geni o'lchami va ketma-ketligi jihatidan bir xil bo'lgan 18 ta ekzonni o'z ichiga oladi (shuningdek, 17 intron). FISH tomonidan aniqlangan 3q26 PKCi geni (ma'lumotlar ko'rsatilmagan). 12-xromosomada PKCI ketma-ketligi uchun hech qanday FISH signali kuzatilmaganligi sababli, bu ko'rinadigan "yuqori darajada saqlanib qolgan genlarning duplikatsiyasi" katta ehtimollik bilan silikada mavjud ketma -ketlikda xatolar mavjudligini tasdiqlovchi qoralama ketma -ketligini yig'ishda xatolik.

PKCγ, ζ va θ o'z xromosomalarining eng distal qismlari bilan xaritada topilgan (19q13.4da PKCγ, 1p36.3da PKCζ va 10p15 da PKCθ), bu genlar ifodasini o'zgartiruvchi telomerik pozitsiya effekti bo'lishi mumkinligini ko'rsatadi. inson hujayralarining takrorlanish muddati. Biroq, hozircha bu borada eksperimental dalillar yo'q.

PKC gen modulining genomik tashkiloti

HUGO va bioinformatika vositalaridan foydalanib, biz to'qqizta PKC izotipi genlarining genomik tashkilotini, ya'ni ekson/intron strukturasining tavsifini ajratib oldik (3-rasm). PKC lokuslarining o'lchamlari taxminan 24,4 kilobaza (kb) (PKCg) dan 480 kb (PKCa) gacha va 14 dan 18 gacha kodlash ekzonlari va 13 dan 17 gacha intronlardan iborat bo'lib, o'lchamlari 94 dan 188 435 ta asosiy juft (bp) gacha o'zgarib turadi. . Eksonlar kichik va o'rta kattalikdagi, 32 dan 381 nukleotidgacha. Barcha intron-ekson birikmalari GT-AG qoidasiga mos keladi. Bu genlar oilasining umumiy evolyutsion kelib chiqishini hisobga olsak (PKC ning cDNA asosli filogenetik daraxti va uning eng yaqin qarindoshi PKD, 3a-rasm), ularning ekzon tuzilmalarining bir xil (va deyarli bir xil o'xshashligi) ajablanarli emas. aminokislotalar ketma-ketligi) PKC subfamilyalari ichida (3b-rasm). PKCa, b, γ, ε, ζ va of ORFlari uchun AUG tarjimasini boshlash joyi ekzon 1da, PKCδ, θ va í uchun bitta intron 5'-tarjima qilinmagan mintaqada joylashgan (5'-UTR) va faqat keyingi ekzonlar PKC oqsillarining funktsional sohalarini aniqlaydi. Shunga qaramay, 5'-UTR ichida qo'shimcha ekonlar mavjudligini istisno qilib bo'lmaydi.

To'qqiz xil inson PKC genlarining evolyutsion aloqalari va tuzilmalari. (a) PKD izotiplarining cDNA asosidagi filogenetik daraxti va ularning eng yaqin qarindoshi PKD. (b) PKC genomik gen ketma-ketliklari o'rtasidagi evolyutsion taqqoslash subfamilaga xos genomik tashkilotni aniqladi. Subfamiliyalar ichida (qatorlarga guruhlangan) rang kodlash lokuslar orasidagi saqlangan ekzon o'lchamlarining har xil to'plamlarini ko'rsatadi.

Ushbu tizimli genom ma'lumotlari PKC genlarining filogenetik aloqalarini ifodalash uchun ishlatilishi mumkin. PKC ning tartibga soluvchi va katalitik subdomainlarining tashkil etilishi evolyutsiya davomida sezilarli darajada saqlanib qoldi: PKCa ning ekzon tuzilmasini mos yozuvlar sifatida ishlatib, katalitik domen ichidagi 10-15 ekonlari an'anaviy (v. ) PKC va yangi (n) PKC, lekin atipik (a) PKC emas. aPKCζ va í katalitik domenning ekzon tuzilmasida cPKC va nPKCdan juda farq qiladi. Ushbu yo'nalishda aPKCy va aPKC'lar tartibga soluvchi va katalitik domen tuzilmalarida bir-birlari orasida ayniqsa saqlanib qolgan ko'rinadi. Tartibga soluvchi sohada cPKC, nPKC va aPKC subfamiliyalari bir-biridan aniq farq qiladi va hatto nPKClar ichida D-shakllarga, PKCd va th va E-shakllarga, PKCe va ēga bo'linish mavjud. Shuningdek, cPKCa va cPKCβ cPKCγ ga qaraganda bir -biriga yaqinroq ko'rinadi. Umuman olganda, ma'lumotlar shuni ko'rsatadiki, genlarning takrorlanishi, so'ngra intron yo'qolishi va/yoki qo'shilishi va ekzon aralashishi PKC genlar oilasi evolyutsiyasida muhim rol o'ynagan. Bu ehtiyot silikada genning nozik tuzilishini disektsiya qilish ham PKC genlaridagi potentsial anormalliklarni samarali izlash uchun zarur shartdir.

PKC gen transkriptlarini muqobil qayta ishlash

Muayyan to'qimalarda PKCning alternativ biriktiruvchi variantlarining mavjudligi, bu hujayralar ichidagi signal uzatilishining xilma -xil yo'llarini aks ettiruvchi, PKCda yanada xilma -xillikni ta'minlashning jozibali variantidir.

Muqobil birlashma hozirda kamida bitta inson PKC izotipi uchun ma'lum. 671 va 673 aminokislotalarning ketma-ketligini kodlaydigan ikkita alohida PKCb cDNA klonlari ajratilgan, ular bir-biridan faqat 50 ga yaqin aminokislotalarning karboksi-terminalli hududlarida farq qiladi [14,15]. PKCb xromosoma genining xarakteristikasi ikkita qo'shni karboksi-terminalli ekzonlar mavjudligini to'g'ridan-to'g'ri isbotlab berdi, ular muqobil ravishda ikki turdagi PKCb hosil qilish uchun biriktirilishi mumkin edi [16]. Muhimi, bu bo'linish variantlari, PKCbI va bII, to'qima-selektiv tarzda ifodalangan ko'rinadi, bu ularning vazifalari boshqacha ekanligini ko'rsatadi.

Kemiruvchilarda PKC biriktiruvchi variantlari ma'lum

PKCd ning sichqoncha varianti - PKCdII - yaqinda tasvirlangan [17]. Bu asl PKCδI ketma-ketligining V3 sohasidagi kaspaz-3 sezgir joyiga 78 bp (26 ta aminokislota) kiritishga ega, bu esa PKCIIII izoformini kaspaz-3 ga sezgir qilmaydi. PKCδI ko'p to'qimalarda aniqlanadi, PKCIIII moyak, tuxumdon, timotsitlar, miya va buyraklarda tanlab ifodalanadi [18].

Bundan tashqari, kalamushlarda PKC3IIIning karboksi-terminalli kesilgan shakli mavjud bo'lib, u V3 mintaqasida o'sha joyga 83 bp freymdan tashqari joylashtirilgan [18]. Genomik DNK tahlili shuni ko'rsatdiki, sichqoncha PKCDII va kalamush PKCdIII o'rtasidagi farq muhim 5' donor qo'shilish joylaridagi boshqa ketma-ketlik bilan bog'liq (ma'lumotlar ko'rsatilmagan). Faqat tartibga soluvchi sohani ifodalovchi PKCdIII, PKCdI ga qarshi dominant-salbiy ta'sir ko'rsatishi mumkin va shuning uchun ushbu variantni o'z ichiga olgan muqobil birlashma signal yo'llarini modulyatsiya qilishi mumkin.

Har xil 5' uchlari bo'lgan kalamush PKCz RNKning ikkita shakli haqida xabar berilgan. Asosiy shakl (yovvoyi turdagi PKC) hamma joyda ifodalanadi, kichik shakli - ferment kinaz M -PKM (PKMζ) - fermentning ko'p katalitik sohasini tartibga soluvchi domenidan ko'p bo'lmagan holda, u oddiy miyada va ma'lum kalamushlar prostatida ustunlik qiladi. o'smalar. Sichqoncha PKCz gen lokusu ikkita muqobil promouterni o'z ichiga olgan ko'rinadi, ulardan transkripsiya qilinib, 5'-uchli heterojenlik bilan ikkita transkript berish mumkin [19].

Nihoyat, sichqon moyagidan PKCθII cDNA kloni ajratilgan bo'lib, u 20 ta aminokislotadan iborat noyob 5 'ketma -ketlikni va 444 ta aminokislotalarning PKCII (= yovvoyi turi) ketma -ketligini kodlaydi. PKCIIII RNK transkripsiyasi PKCII genining 7 va 8 ekonlari orasida joylashgan PKCIIII o'ziga xos ekzonidan boshlanadi, bu shuni ko'rsatadiki, muqobil biriktirish PKCIIII hosil qilish mexanizmidir. PKCHII faqat moyaklarda jinsiy etilish bilan yoshga bog'liq holda ifodalanadi. C1 tartibga soluvchi domenining yo'qligi bilan mos ravishda, PKCOHII konstitutsiyaviy faoldir va spermatogenezda hal qiluvchi rol o'ynashi mumkin [20].

Odam PKC gen moduli ichida bitta nukleotidli polimorfizmlarni aniqlash

Inson genomida bitta nusxada mavjud bo'lgan haqiqiy PKC gen lokuslari Milliy Biotexnologiya Axborot Markazi veb-sayti [21] manbalaridan foydalangan holda bitta nukleotidli polimorfizmlar (SNP) uchun batafsil tahlil qilingan. Hozirgi vaqtda ushbu ma'lumotlar bazasi qidiruvlaridan ma'lum bo'lgan PKC gen modulining kodlash hududlaridagi 11 ta SNPlar orasida faqat ikkitasi (PKCδ va PKCηda har biri bittadan) sinonim bo'lmagan kodonlarni keltirib chiqaradi va missensiya mutatsiyasini hosil qiladi (2-jadval). Ushbu noto'g'ri mutatsiyalar kinaz funktsiyasiga hech qanday aniq ta'sir ko'rsatmaydi, garchi hozirgi vaqtda ta'sirni istisno qilish mumkin emas. Umuman olganda, inson PKC genlari SNP tahlili bilan tavsiflanadigan darajada o'zgaruvchan mintaqalar emas, ammo mavjud ekzonik SNPlar bog'lanish va/yoki assotsiatsiyaviy tadqiqotlarda gaplotiplash maqsadlarida foydalanish uchun etarli ko'rinadi.

Inson kasalligi lokuslari bilan PKC gen lokuslarining mayda xaritasi xromosomal joylashuvi

Saraton genomining anatomiyasi loyihasi [22] yordamida, bu to'qqizta mayda xaritali PKC lokuslarining xromosomal joylashuvini odam kasalligi lokuslari bilan taqqoslash natijasida, masalan, malign kasalliklari bo'lgan bemorlarda, bu hududlarda xromosoma aberatsiyasi/to'xtash nuqtalari aniqlandi (4-rasm). Xususan, 17q24 (PKCa), 19q13 (PKCg), 3p21 (PKCd), 2p21 (PKCe), 1p36 (PKCĶ) va 3q26 (PKCi) joylari diqqatga sazovordir, chunki bu xromosal hududlarda o'chirish yoki muvozanatli translokatsiyalar tez-tez tavsiflanadi. tabiiy ravishda paydo bo'lgan malign o'smalarda. Shunday qilib, nazariy jihatdan, PKC oilasi genlari, intraxromosomalarni qayta tashkil etish yoki hatto xromosomalararo translokatsiyalar paytida tasodifiy rekombinatsiyalarda kasallik nomzodi genlari sifatida ta'sir qilishi mumkin. abl immunoglobulinga ketma-ketliklar yoki bcr Lokuslar malignizatsiyaga olib keladi (funktsiyani oshirish orqali). Shu bilan birga, hujayraning faollashishi, ko'payishi va apoptozini tartibga soluvchi boshqa ko'plab genlar ham bu xromosoma mintaqalariga kiradi. Shunga qaramay, bizning xaritalash natijalarimiz shuni ko'rsatadiki, ba'zi PKC izotiplari inson saratoniga aloqador nomzod genlar bo'lishi mumkin.

Saraton genomi anatomiyasi loyihasi [37] ma'lumotlaridan foydalangan holda, inson PKC gen lokuslarini o'smalarda muvozanatli aberatsiyalarning xromosoma lokalizatsiyasi bilan taqqoslash. Har bir gen lokusu strukturasi diagrammasining o'ng tomonida sanab o'tilgan xromosoma anomaliyalari ma'lumotlariga qo'shimcha ravishda, genning to'qimalar ifodasi (ekspresslangan ketma-ketlik yorlig'i (EST) ma'lumotlar bazalaridan) va ma'lum inson mutatsiyalari haqida ma'lumot berilgan [38,39]. PKC lokuslarining bir nechtasi e'tiborga loyiqdir, chunki bu xromosoma mintaqasidagi o'chirish yoki translokatsiya hodisalari inson neoplaziyasida takroriy xromosoma o'zgarishlarining uzilish nuqtasi xaritasida tasvirlangan [22,37]. Barcha gematologik malign o'smalarda va qattiq o'smalarda takrorlanuvchi muvozanatli xromosoma aberatsiyasi bo'yicha sitogenetik tadqiqotlar [37] da chop etilgan.

PKC oilasi a'zolari har xil hujayralarni, shu jumladan T hujayralarini apoptozdan himoya qilish uchun ko'rsatilgan o'simtani qo'zg'atuvchi forbol efirlari uchun hujayra ichidagi retseptorlari sifatida malign transformatsiyaga hissa qo'shadigan aberrant signal reaktsiyalarida doimiy ravishda ishtirok etganlar [23,24] ]. PKC-oilaviy genlarning bu potentsial o'zgaruvchan qobiliyati natijasida, ko'pchilik o'simta hujayralarida topilgan PKC izotiplarining g'ayritabiiy darajada yuqori ifodasi PKC va onkogenez o'rtasidagi funktsional bog'liqlikni tasdiqlaydi (G.B., nashr etilmagan ish). T-hujayrali leykemiya bilan og'rigan bemorlardan olingan hujayra liniyalarida PKCth ning (aniqlanmagan mexanizm bo'yicha) malign hujayralarning membrana fraktsiyasiga surunkali jalb qilinishi haqida xabar berilgan [25]. Boshqa aniqroq natijalar shuni ko'rsatadiki, Bcr-Abl va PKCi faolligi gematopoetik K562 hujayralarida apoptozga qarshilik ko'rsatish uchun zarur bo'lib, leykemiya hujayralarining omon qolishida PKCi funktsional rolini qo'llab-quvvatlaydi [26]. So'nggi tadqiqotlar, shu jumladan o'zimizning [23,27], aniq PKC izotiplarini apoptozni tartibga soluvchi molekulyar yo'llar bilan bevosita bog'ladi. Ammo hujayrali o'sishni nazorat qilish va differentsiatsiyalashda PKClarning taxminiy roliga qaramay, PKClarning hujayrali birlamchi malignizatsiyadagi sababchi rolining klinik namunasi hali chop etilmagan. Tabiiy kelib chiqadigan badandagi somatik hujayrali mutantlarning genetik diseksiyasi oxir -oqibat PKC va klinik kasallik o'rtasida aloqa o'rnatadimi yoki yo'qligini aniqlash kerak.

Endi aniq genetik sindromlar bilan bog'liq bo'lishi mumkin bo'lgan PKC lokuslarida potentsial funktsiyani yo'qotish (va, ehtimol, retsessiv) mutatsiyalar uchun yo'naltirilgan qidiruv boshlanadi. Signallarni uzatish bo'yicha biokimyoviy ishlardan olingan ma'lumotlar bilan bir qatorda, PKC izotipining nokaut chiziqlari ([28,29,30,31,32,33] va Gb, nashr etilmagan ishi). ), bu erda keltirilgan genomik nozik xaritalash bemorlarning ma'lum guruhlarida genetik tadqiqotlar o'tkazishga PKC funktsional polimorfizmlarini yoki oilaviy genetik nuqsonlar yoki anomaliyalar bilan bog'liq mutatsiyalarni qidirish imkonini beradi. Genetika va molekulyar ma'lumotlar bazalarining ulkan o'sishini hisobga olgan holda, bioinformatika yondashuvlari takomillashtirilishi va farazlarni baholash uchun foydali vositalarga aylanishi davom etishi kerak, bunda faqat eng istiqbollilari empirik sinovdan o'tkaziladi. Ushbu inson genetikasi va shuning uchun uzoq muddatli yondashuv PKC gen modulining asosiy fiziologik va mumkin bo'lgan patofiziologik funktsiyalarini aniqlashga yordam beradi va PKClarning inson genetik kasalligiga qanday aloqasi borligini va oxir-oqibatda qandayligini yoritishi mumkin.


Muhokama

Bu erda A188 genomlari yig'ilishi uzoq o'qiladigan texnologiyalar, shu jumladan Nanopore bitta molekulali o'qish va uzoq masofali optik xaritalashni o'z ichiga oladi, bu esa makkajo'xori genomlari to'plamiga yangi yuqori sifatli mos yozuvlar genomini qo'shadi [8,9,10,11, 12,13,14,15,16]. O'rnatish sifati, DNKning ikkita mustaqil manbalaridan qisqa o'qilgan ma'lumotlarning o'qish chuqurligini iskala oldidan filtrlarni tekshirish uchun solishtirish strategiyasi bilan yaxshilandi. Mustaqil DNK manbalaridan foydalanish yadro bilan birlashtirilgan organellalar ketma-ketligini saqlab qolgan holda, organella genomlari va mikroorganizmlarning DNK ketma-ketligidan ifloslanishni kamaytirdi. Bundan tashqari, ketma-ket o'qish chuqurligini miqdoriy taqqoslashga asoslangan genomning strukturaviy o'zgarishini kashf qilishning yangi yondashuvi joriy etildi, bu erda qiyosiy genomik o'qish chuqurligi yoki CGRD deb nomlanadi. Makkajo'xori kabi murakkab genomlarning genomik strukturaviy o'zgarishini batafsil tavsiflash qiyin. To'liq genom ketma-ketligini ularning hizalanishlari asosida taqqoslash nusxa ko'chirish sonining o'zgarishi va qayta tashkil etilishini aniqlash uchun ideal usul bo'ladi. Biroq, texnik jihatdan, hizalamaga asoslangan usullar hali ham takrorlanuvchi ketma-ketliklarni ishonchli tekislash qobiliyatidan aziyat chekmoqda. Muhimi, yig'ilgan genom ketma-ketligi bilan strukturaviy o'zgarishlarni topish yig'ilishlar sifatiga bog'liq. Afsuski, ko'pchilik o'simlik genomlari yoki boshqa yirik murakkab genomlarning yig'indilari odatda to'liq yoki xatosiz emas. Masalan, B73Ref4 6-xromosomaning qisqa qo'l ketma-ketligining eng yuqori qismiga ega emas (Qo'shimcha fayl 1: S13-rasm) va bir nechta yig'ilish inversiyasi xatolarini o'z ichiga oladi. Qisqa o'qish chuqurligini taqqoslashga asoslangan CGRD, genomning to'liq moslanishiga, shu jumladan SyRIga asoslangan yondashuvlarni to'ldiradi [32]. Xususan, CGRD quvur liniyasi tizimli murakkab hududlarda to'liq yig'ilmaganligi sababli SyRI tomonidan o'tkazib yuborilgan nusxalar sonining o'zgarishini aniqlay oladi. CGRD-da 1.8 Mb hajmdagi dublikat aniqlandi Ga1 lokus va yuqori nusxadagi tandemning takrorlanishi Wc1 A188 da, ikkalasi ham SyRI tomonidan o'tkazib yuborilgan. Ikki usul bir-birini to'ldiradi, chunki CGRD SyRI aniqlay oladigan muvozanatli tarkibiy o'zgarishlarni emas, balki nusxa ko'chirish sonining o'zgarishi sababli muvozanatsiz tarkibiy o'zgarishlarni ushlaydi. Shu sababli, SyRI va CGRD kombinatsiyasi genomik strukturaviy o'zgarishlarni kashf qilish uchun maqbul strategiyani taqdim etadi, bu ularning gen ekspresiyasi va fenotiplariga ta'sirini yanada tavsiflash uchun juda muhimdir.

Strukturaviy o'zgarishlarni tahlil qilish uning takrorlanuvchi tuzilishini aniqladi ccd1 gen, A188 da 13 nusxadan iborat. Yuqori nusxalar soni ccd1 ning yuqori ifoda darajasiga mos keladi ccd1Bu ilgari kuzatilgan va ehtimol karotenoid parchalanish fermentining yuqori faolligiga va karotenoidlarning parchalanishiga olib keladi [37]. Bundan tashqari, ifodasi y1, fitoen sintazasini va karotenoid yo'liga kirish reaktsiyasini kodlaydi, A188 da urug'larning rivojlanishida past bo'ladi, shu bilan birga y1 B73 urug'larida ifoda nisbatan yuqori [48]. Ikkala allel ham ba'zi urug' bo'lmagan to'qimalarda, shu jumladan barglarda yuqori darajada ifodalangan. A188 y1 allel, ehtimol, funktsionaldir, chunki urug 'rivojlanishida karotenoidlarning past, lekin seziladigan darajasi hosil bo'ladi. Qo'shimcha kichik yadro rangi QTL DH liniyalaridan aniqlandi va B73-dan olingan boshqa ota-ona populyatsiyalarining QTL-lariga mos keladi [49]. Asosiy nomzod gen, zep1 (Zm00001d003513) zeaksantin epoksidazani kodlovchi ham oldingi assotsiatsiya tadqiqotida aniqlangan edi [50]. Biroq, ishtirok etish uchun funktsional tekshirish zep1 urug'ning rangi kerak. Shu bilan birga, uchta QTL lokuslari DH liniyalarining yadro rangi o'zgarishini to'liq aniqlash uchun etarli emas. Kattaroq B73xA188 populyatsiyasi bilan tahlil yadro ranglariga ta'sir qiluvchi qo'shimcha lokuslarni ko'rsatishi mumkin, chunki barcha DH liniyalari bog'langan QTLlar asosida kutilgan rangga ega emas. Har qanday holatda ham, karotenoid darajasi allel turlariga qarab kutilgan edi y1 va ccd1 va yuqori darajadagi gipotezani qo'llab -quvvatladi ccd1 va past y1 A188 va B73 urug 'ranglarining farqiga hissa qo'shadi.

A188 tavsifining muhim maqsadi o'simlik to'qimalarining madaniyati haqida tushunchaga ega bo'lishdir. Genetik muhandislik maqsadlarida yuqori darajada tabaqalangan to'qimalardan kallusgacha bo'lgan rivojlanish pluripotentsiyaga erishish uchun dedifferentsiyalash jarayonini o'z ichiga oladi [51]. Differentsial holatning o'tishi, fiziologik jihatdan, stressdir [52]. To'qimachilik madaniyati orqali ishlab chiqariladigan o'simliklarning somaklonal o'zgarishi, shu jumladan bepushtlik, DNKning stressga javob reaktsiyasi natijasida paydo bo'lishi mumkin [53]. Ushbu tadqiqotdan olingan transkriptomik ma'lumotlar shuni ko'rsatdiki, boshqa to'qimalarga qaraganda kallusda yuqori darajada tartibga solingan kalusli genlar orasida mudofaa javob genlari boyitilgan. Gipermetilatsiya genom barqarorligini oshiradigan va genom yaxlitligini himoya qiluvchi stresslardan himoya mexanizmi hisoblanadi [54]. Kallus va ko'chat o'rtasidagi taqqoslashimiz barcha uchta ketma-ketlik kontekstida kallusda global darajada ko'tarilgan metilatsiyani aniqladi. Izchil ravishda, etuk embrionga nisbatan kallusdagi gipermetilatsiya boshqa makkajo'xori inbred liniyasi va metillangan DNK immunoprecipitatsiya sekvensiyasi (MeDIP-seq) qo'llanilgan tadqiqotda aniqlandi [55]. Ushbu tadqiqotda 24 nt kichik RNK DNK metilatsiyasi bilan ijobiy bog'liqligi ko'rsatildi. Guruchda guruch mutantidagi otishga nisbatan 1 va 3 yillik kalluslarda CG gipermetilatsiyasi kuzatilgan. MET1-2, bu CG metilatsiyasini saqlashda katta rol o'ynaydigan DNK metiltransferazasini kodlaydi. Yovvoyi turdagi guruchda faqat CHH gipermetilatsiyasi kuzatildi [52]. Bizning tadqiqotimizda kallus va ko'chatlarni taqqoslash A188 ekanligini ko'rsatdi MET1-2 homolog (Zm00056a035610) edi

Kallusda 2 marta yuqoridan tartibga solinadi va mop1 (Zm00056a013519), 24 nt kichik RNK [56] ishlab chiqarishda ishtirok etadigan RNK-ga bog'liq bo'lgan RNK-polimeraza 2 gomologi, kallusda 5-6 marta yuqoriga qarab tartibga solingan, bu transkriptomik uskunalar global miqyosni yaxshilash uchun tartibga solinganligini ko'rsatadi. Kallusdagi DNK metilatsiyasi. Kallidan qayta tiklanadigan o'simliklarda CG va CHG metilatsiyasi qayta tiklanmagan o'simliklar bilan solishtirganda yo'q bo'lib ketardi va ko'plab metillanish hodisalari irsiy edi [57]. Qayta tiklangan o'simliklarda irsiy gipometillanish makkajo'xori tadqiqotida ilgari kuzatilgan [58]. Guruchda, guruchda qayta tiklanmagan o'simliklar bilan taqqoslaganda, to'qima madaniyatidan tiklangan o'simliklarda aniq gipometilatsiya aniqlangan [59]. Qayta tiklangan o'simliklar va kalli o'rtasidagi DNK metilatsiyasining bir xil emasligi, to'qima madaniyatidan olingan metilatsiyaning ko'pchiligi barqaror yoki irsiy emasligini ko'rsatdi. Kallusning shakllanishi paytida DNK metilatsiyasi ko'paygan, bu, ehtimol, uyali mudofaa reaktsiyalari tufayli. Olingan DNK metilatsiyasining aksariyati qayta differentsiatsiya paytida demetilatsiyaga uchraydi, natijada gipometilatsiyalangan regeneratsiyalangan o'simliklar paydo bo'ladi.


Meros olish:

Genotip - bu organizmning genetik tuzilishi. Bu genetik kodning bir qismi bo'lgan allellar, masalan balandlik uchun TT, Tt yoki tt.

Fenotip - bu genetik konstitutsiyaning ifodasi va uning atrof -muhit bilan o'zaro ta'siri (individual xususiyat).

Bitta genning ko'plab allellari bo'lishi mumkin, ular uchtadan biri bo'lishi mumkin:

  • Dominant: Xarakterli fenotipda faqat bitta nusxa bo'lsa ham paydo bo'ladigan allel. Bu allellar bosh harflar bilan yoziladi, masalan genotipdagi bosh t, uzun bo'yli uchun genotip misolida ishlatilgan.
  • Retsessiv: Agar dominantdan farqli o'laroq ikkita nusxa bo'lsa, fenotipda xarakterli allel paydo bo'ladi. Bu allellar kichik harflar bilan yozilgan, masalan, uzun bo'yli genotip uchun ishlatilgan genotipdagi kichik harf t.
  • Kodominant: Allellar fenotipda ifodalanadi va ikkita katta harf bilan ifodalanadi, bunda bitta allel alleli boshqa bosh harfning ustidan yoziladi, masalan, snapdragonning rangi C R = Qizil gullar va C W = Oq gullar:

Diploid organizmda (biz odamlar kabi, bizda ikkita xromosoma to'plami mavjud) ma'lum bir joydagi (xromosomadagi joylashuv) allellar bo'lishi mumkin:

  • Homozigot: Genotipda bir xil allelning ikkita nusxasiga ega bo'lgan organizm, masalan, TT yoki tt. Organizm gomozigota deyiladi.
  • Geterozigotli: Genotipda ikki xil allelni tashuvchi organizm, masalan Tt. Aytishlaricha, organizm heterozigota.

Eslatma: Quyidagi genetik diagrammani bilish kerak, chunki sizdan imtihonda naslning genotiplari va fenotiplarini bashorat qilish so'raladi. Monohibrid meros - bu bitta gen tomonidan boshqariladigan bitta xususiyatning merosxo'rligi. "Monogibrid xoch" (T allelli rasm) degan tasvirlar imtihonda tavsiya etilgan sxemani ko'rsatadi va bu monogibrid xochlar homozigotli dominant, geterozigotli dominant va gomozigotli retsessiv o'rtasidagi barcha mumkin bo'lgan kombinatsiyalarni qamrab oladi. Bu allellar autosomal genlarda joylashgan. Avtosomalar - bu jinsiy xromosoma bo'lmagan xromosomalar.

C W allellari bilan monogibrid o'zaro faoliyat tasvir ham quyidagi manbaning bir qismidir. Bu allellar autosomaning bir qismidir.

Ba'zi genlarda bir nechta allellar mavjud bo'lib, ularda ikkitadan ko'p bir xil gen uchun kodlash mumkin, ammo bu allellardan faqat ikkitasi avlod fenotipida namoyon bo'lishi mumkin, chunki ikkita ota-ona ishtirok etadi. Bu qon guruhining namunasidir, u ham ‘monohibrid xoch va bir nechta allellar nomi bilan tasvirdir (I va I O allellari). Bu allellar autosomaning bir qismidir.

Kistik fibroz (CF) gomozigotli retsessiv odamda retsessiv allel tufayli yuzaga keladi. Qalin, yopishqoq shilimshiq hosil bo'ladi va o'pkaning shilliq qavatida qoladi. Bu allellar autosomaning bir qismidir.

Albinizm - bu irsiy kasallik, bu erda sochlar, iris va teri kabi tuzilishga ega bo'lgan melanin rangining etishmasligi mavjud. Shuning uchun albinoslarning ko'zlari qizil, terisi pushti va och sariq sochlari bor. It caused by a single recessive allele in the genotype. These alleles are part of the autosome.

Huntington’s disease, an incurable and fatal disease, is caused by a dominant allele in the genotype. These alleles are part of the autosome.

There is a 50-50 chance that a baby can be a boy or a girl. This can be proved by the Punnett square which is shown by the image called 󈧶-50 chance of being a boy or a girl’.

Sex linked characteristics are carried on the X of the sex chromosomes therefore the genes are not autosomal. An example of this is colour blindness which is the image called ‘colour blindness’. Boys are more likely to be colour blind than girls as boys only have one X chromosome. If this chromosome has the allele then he is colour blind. Girls have two X chromosomes and therefore the two are needed to have the allele for her to be colour blind.

Dihybrid inheritance is where two characteristics are adopted by two different alleles on different loci. An example follows:

Misol: Two pea plants each with the genotype RRYY and rryy were crossed to create the first generation of offspring all with the genotype of RrYy. Two of the offspring were crossed to create the second generation of offspring. R is for round, r is for wrinkled, Y is for yellow and y is for green. NB: There has to be the two different types of alleles controlling a different characteristic in the same gamete as this is dihybrid inheritance – the inheritance of two characteristics. The other parent has the phenotype wrinkled and green with the genotype rryy so the gametes will be ry and ry. As the table below represents the offspring of the second generation, both parents have the genotype RrYy giving the gametes RY, Ry, rY and ry (the possible combinations of two different alleles controlling different characteristics:

RYRyrYry
RYRRYYRRYyRrYYRrYy
RyRRYyRRyyRrYyRryy
rYRrYYRrYyrrYYrrYy
ryRrYyRryyrrYyrryy

From the offspring above a phenotypic ratio can be concluded showing the two characteristics i.e. the phenotypic ratio for the offspring above is: 9 round and yellow seeds: 3 round and green seeds: 3 wrinkled and yellow seeds: 1 wrinkled and green seed.

If there were 16 offspring, 9 of the offspring would have round and yellow seeds, 3 would have round and green seeds, another 3 would have wrinkled and yellow seeds and 1 would have wrinkled and green seeds as this is the expected value. Not all cases are like this where another set of 16 offspring either from the same parents or different parents of the same genotype as RrYy may have 10 that have round and yellow seeds, 2 that have round and green seeds, 4 that have wrinkled and yellow seeds and none of the offspring have wrinkled and green seeds instead of the classic 9:3:3:1 ratio. This is our observed value. So, how would we know if the difference of the expected values and observed values are due to chance? Solution: Chi-squared should be used.

NB: You are not expected to work out chi squared in the exam however a demo will be given below following the same type of plant and crossing as the one above.

We have to come up with our null hypothesis which is: THERE IS NO SIGNIFICANT DIFFERENCE BETWEEN THE OBSERVED AND EXPECTED RESULTS.

It is best if you put your data in a table like the one below:

OEO – E(O – E) 2(O – E) 2 /E
Round and yellow seeds109111/9
Round and green seeds23-111/3
Wrinkled and yellow seeds43111/3
Wrinkled and green seeds01-111

As the chi squared formula has the funny symbol in front of the fraction which means sum of, all the values at the furthest right of the table above have to be added up to give chi-squared. Chi squared is therefore 16/9. This value should be referred to the table below:

Probability, p
Degrees of freedom0.25 (25%)0.20 (20%)0.15 (15%)0.10 (10%)0.05 (5%)0.02 (2%)0.01 (1%)
11.321.642.072.713.845.416.63
22.773.223.794.615.997.829.21
34.114.645.326.257.819.8411.34
45.395.996.747.789.4911.6713.28
56.637.298.129.2411.0713.3915.09

NB: We should always use the column with the 0.05 or 5% probability highlighted in yellow as biologists always use this. The values in the table are known as critical values.

To know which degrees of freedom to use we must use the value that is 1 minus how many categories we have. So in this case as we have four categories (the different types of seeds that the offspring have), we subtract 1 from this and we get three which is our degrees of freedom. Therefore our critical value is 7.81 which is in bold and underlined. We compare our chi-squared value (16/9) to the critical value (7.81). Our chi-squared value is smaller than the critical value therefore we accept our null hypothesis saying also that there is a 5% or higher probability that the results are due to chance and there is no significant difference between observed and expected values. NB: If our chi-squared value was greater than the critical value then we reject our null hypothesis and also say that there is a 5% or lower probability that the results are not due to chance and there is a significant difference between observed and expected values.

Epistasis is where a gene interferes with another gene on a different locus. An example is as follows: Flowers can be either white, light blue or aqua blue. The alleles of the gene code for the enzyme used to catalyse the reaction between white and light blue and light blue and aqua blue. The reaction between white and light blue is controlled by an enzyme called Enzyme A, coded by the dominant allele A. The reaction between light blue and aqua blue is controlled by Enzyme B coded by the dominant allele B. An image with the title ‘Epistasis’ is on the resource for you to look at.

Linkage is where there are two alleles that code for a different characteristic on the same chromosome. Therefore variation is reduced. An example is sweet pea plants in the image named ‘linkage’.

Recombination is the reassortment of genes into different combinations from the parents. Offspring that have recombination are called recombinants and gives rise to different individuals in a natural population. Three things can give rise to recombination: crossing over, independent assortment/segregation and random fertilization.

6 POINTS ON HOW TO ANSWER ‘LOOKING FOR EVIDENCE’ QUESTIONS IN GENETICS

  1. A TIP TO REMEMBER IS NEVER ASSUME THAT A GENETIC CROSS OR PEDIGREE DIAGRAM IS SEX-LINKED UNLESS IT TELLS YOU IN THE QUESTION.
  2. Q1:WHAT IS THE EVIDENCE THAT AN ALLELE IS RECESSIVE?

Nimani izlash kerak:LOOK FOR PARENTS WHO ARE UNAFFECTED AND HAVE A CHILD WHO IS AFFECTED.

Tushuntirish:PARENTS MUST BE HETEROZYGOUS BECAUSE THEY ARE UNAFFECTED AND ALSO THEY PASS ON THEIR RECESSIVE ALLELE TO THEIR CHILD.

Nimani izlash kerak:LOOK FOR TWO PARENTS WHO ARE AFFECTED AND HAVE A CHILD THAT IS NOT AFFECTED.

Tushuntirish:PARENTS MUST HETEROZYGOUS BECAUSE THEY ARE AFFECTED AND ALSO THEY PASS ON THEIR RECESSIVE ALLELE TO THEIR CHILD.

Nimani izlash kerak: LOOK FOR A MOTHER WITHOUT THE CONDITION AND A SON WITH THE CONDTION.

Tushuntirish: MUM MUST BE HETEROZYGOUS FOR HER TO NOT HAVE THE CONDITION.

Nimani izlash kerak: LOOK FOR UNAFFECTED FATHER AND AFFECTED DAUGHTER.

Tushuntirish: DAUGHTER MUST HAVE TWO RECESSIVE ALLES BUT COULD NOT INHERIT THE RECESSIVE ALLELE FROM DAD BECAUSE HE IS UNAFFECTED.

Nimani izlash kerak: LOOK FOR AN AFFECTED FATHER AND UNAFFECTED DAUGHTER.

Tushuntirish: IF FATHER’S X CHROMOSOME CARRIES THE DOMINANT ALLELE THE DAUGHETR WOULD BE AFFECTED WHICH IS NOT THE CASE.


Selina Concise Biology Class 10 ICSE Solutions Genetics Some Basic Fundamentals

APlusTopper.com provides step by step solutions for Selina Concise ICSE Solutions for Class 10 Biology Chapter 3 Genetics Some Basic Fundamentals. You can download the Selina Concise Biology ICSE Solutions for Class 10 with Free PDF download option. Selina Publishers Concise Biology for Class 10 ICSE Solutions all questions are solved and explained by expert teachers as per ICSE board guidelines.

Selina ICSE Solutions for Class 10 Biology Chapter 3 Genetics – Some Basic Fundamentals

Solution A.1.
d) Ascaris

Solution A.2.
a) 3 : 1

B.1 yechim.
(a) – (iii) Study of laws of inheritance of characters
(b) – (v) Chromosomes other than the pair of sex chromosomes
(c) – (iv) A gene that can express when only in a similar pair
(d) – (ii) The alternative forms of a gene
(e) – (i) Chromosomes similar in size and shape

B.2 -yechim.
Lion, tiger, domestic cat (Any two)

B.3 yechimi.
Colour-blindness, Thalassaemia, Sickle cell anaemia and Haemophilia (Any two)

Solution B.4.
Homozygous dominant – RR
Homozygous recessive – rr

Qaror C.1.

Fenotip Genotip
The observable Characteristic which is genetically controlled is called phenotype. The set of genes present in the cells of an organism is called its genotype.

Xarakter Xususiyat
Any heritable feature is called a character. The alternative form of a character is called trait.

Monogibrid xoch Dihibrid xoch
It is a cross between two pure breeding parent organisms with different varieties taking into consideration the alternative trait of only bitta belgi It is a cross between two pure breeding parent organisms with different varieties taking into consideration the alternative trait of ikkicharacters.

Qaror C.2.
The characteristics of a species such as physical appearance, body functions and behavior are not only the outcome of chromosome number, but these depend on the genotype of every organism. That means the set of genes present in the organisms may very and therefore lion, tiger and domestic cat have the same number of 38 chromosomes, their characteristics (like different appearances) are the result of the genes located on the chromosomes.

Qaror C.3.

Xarakter Dominant trait Resessiv xususiyat
Flower Colour Siyohrang Oq
Seed Colour Sariq Yashil
Seed Shape Dumaloq Ajin
Pod Shape Inflated Constricted
Flower Position Axial Terminal

Qaror C.4.

  • Colour-blindness is caused due to recessive genes which occur on the X chromosome.
  • Males have only one X chromosome. If there is recessive gene present on X chromosome, then the male will suffer from colour-blindness.
  • Females have two X chromosomes. It is highly impossible that both the X chromosomes carry abnormal gene. Hence, if one gene is abnormal and since it is recessive, its expression will be masked by the normal gene present on the other X chromosome. Females are unlikely to suffer from colour-blindness.

Qaror C.5.
Phenotypic Ratio – 3 (Black Fur) :1 (Brown Fur)
Genotypic Ratio – 1(Homozygous Black Fur):2 (Heterozygous Black Fur): 1 (Homozygous Brown Fur)

Qaror D.1.

(a) Geterozigotli: The condition in which a pair of homologous chromosomes carries dissimilar alleles for a particular character.

  1. A daughter (XX o ) from a normal homozygous mother for colour vision (XX) and a colour blind father has one normal and one defective allele (X o Y).
  2. Certain tongue rollers are heterozygous with Rr genotype.

(b) Homozigot: The condition in which a pair of homologous chromosomes carries similar alleles for a particular character.

  1. A colorblind daughter (X o X o ) will have both the X chromosomes with defective alleles.
  2. A non-roller will have rr (homozygous) genotype.

(c) Pedigree Chart: A pedigree chart is a diagram that shows the occurrence and appearance or phenotypes of a particular gene or organism and its ancestors from one generation to the next. In the pedigree chart, males are shown by squares and females by circles.

Qaror D.2.
Mendel’s laws of inheritance are:

  1. Law of Dominance: Out of a pair of contrasting characters present together, only one is able to express itself while the other remains suppressed. The one that expresses is the dominant character and the one that is unexpressed is the recessive one.
  2. Law of Segregation : The two members of a pair of factors separate during the formation of gametes. The gametes combine together by random fusion at the time of zygote formation. This law is also known as ‘law of purity of gametes’.
  3. Law of Independent Assortment: When there are two pairs of contrasting characters, the distribution of the members of one pair into the gametes is independent of the distribution of the other pair.

Qaror D.3.

    • The sex of the child depends on the father. The egg contains only one X chromosome, but half of the sperms contain X-chromosome whereas the other half contains Y-chromosome. It is simply a matter of chance as to which category of sperm fuses with the ovum and this determines whether the child will be male or female.
    • If the egg fuses with X-bearing sperm, the resulting combination is XX and the resulting child is female.
    • If the egg fuses with Y-bearing sperm, the resulting combination is XY and the resulting child is male.

    Yechim E.1.

    Yechim E.2.
    (a) Black
    (b) No

    Yechim E.3.

    Yechim E.4.
    (a) Father
    (b) Two sons and three daughters
    (c) The child 1 (daughter) is colour blind
    (d) X chromosome
    (e) Haemophilia

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    Genome structure and evolution of Antirrhinum majus L

    Snapdragon (Antirrhinum majus L.), a member of the Plantaginaceae family, is an important model for plant genetics and molecular studies on plant growth and development, transposon biology and self-incompatibility. Here we report a near-complete genome assembly of A. majus cultivar JI7 (A. majus cv.JI7) comprising 510 Megabases (Mb) of genomic sequence and containing 37,714 annotated protein-coding genes. Scaffolds covering 97.12% of the assembled genome were anchored on eight chromosomes. Comparative and evolutionary analyses revealed that a whole-genome duplication event occurred in the Plantaginaceae around 46-49 million years ago (Ma). We also uncovered the genetic architectures associated with complex traits such as flower asymmetry and self-incompatibility, identifying a unique duplication of TCP family genes dated to around 46-49 Ma and reconstructing a near-complete ψS-locus of roughly 2 Mb. The genome sequence obtained in this study not only provides a representative genome sequenced from the Plantaginaceae but also brings the popular plant model system of Antirrhinum into the genomic age.

    Manfaatlar to'qnashuvi to'g'risidagi bayonot

    Mualliflar hech qanday raqobatbardosh manfaatlarni e'lon qilmaydilar.

    Raqamlar

    Fig. 1. An overview of the genomic…

    Fig. 1. An overview of the genomic features of A. majus JI7.

    Fig. 2. Genome evolution of A. majus…

    Fig. 2. Genome evolution of A. majus .

    Fig. 3. Evolution of flower symmetry and…

    Fig. 3. Evolution of flower symmetry and TCP gene family.

    Left, a phylogenetic tree of…

    Fig. 4. Genomic features of the ψS…

    Fig. 4. Genomic features of the ψS -locus of A. majus and its synteny with…


    Natijalar

    Data pre-processing

    A total of 18 samples of raw RNA-Seq data (Additional file 2: Table S1) were obtained for this study. Of the 18 samples, 3 generated from the trypanosome-infected salivary glands were excluded from further analysis because they contained PCR duplicates. Thus, a total of 15 samples were analyzed (Additional file 2: Table S1). Furthermore, lowly expressed genes were excluded to reduce noise, thus resulting in a total of 7390 genes across the 15 samples.

    The relationship between the samples and the reproducibility of biological replicates was determined using principal component analysis (PCA) and Pearson correlation heatmap analysis prior to (Additional file 3: Figure S1) and after adjusting for batch effects that could have resulted from biological replicates (Fig. 1). The PCA and Pearson correlation heatmap plots showed that the samples grouped together based on the developmental stages of T. Bryusey in the insect vector rather than their biological replicates (Fig. 1). An assessment of the distribution of per-gene read counts per sample showed a median steady-state expression level of

    6.5 log2 counts per million in all the 15 samples (Additional file 4: Figure S2).

    Global gene expression profiles of Trypanosoma brucei. a Principal component analysis (PCA) plot. Each point in the PCA plot represents a sample, and point color indicates a batch that consists of the biological replicates. b Sample correlation heatmap using hierarchical clustering. Color codes along the left side of the sample correlation heatmap indicate samples based on the batch they belong to. MG1 and MG2 are midgut samples, PV2 proventriculus samples, and SA2 salivary gland samples

    Weighted gene co-expression network construction

    A total of 7390 protein coding genes from 15 samples were used for the construction of the co-expression network. Prior to generation of the network, the soft-thresholding power to which co-expression similarity was raised to calculate adjacency was determined by analysis of thresholding powers from 1 to 20. Power 14, the power for which the scale-free topology fitting index (R 2 ) was ≥ 0.8, was chosen (Additional file 5: Figure S3). A total of 28 distinct modules were generated for 7390 protein coding genes from the hierarchical clustering tree (dendrogram) using the dynamic tree cut algorithm (Figs. 2, 3, and Additional file 6: Table S2). The gray module, which contained 59 genes that could not be assigned to any module, was excluded from the analysis (Fig. 3). Thus, a total of 27 modules were used in the subsequent analysis. The module with the least genes (61) was the white module while the turquoise module had the largest number of genes (732) (Fig. 3).

    An illustration of the identified gene co-expression network modules in T. brucei. a Hierarchical cluster dendrogram. The x-axis represents the co-expression distance of the genes, while the y-axis represents the genes. A dynamic tree cutting algorithm identified the modules by splitting the tree at significant branching points. Modules are represented by different colors as shown by the dendrogram. b Co-expression network from weighted gene co-expression network analysis (WGCNA) based on topological overlap measures (TOMs) > 0.3 for visualization. Each point (or node) on the network represents a gene, and points of the same color form a gene module. Lines (edges) on the network connecting the nodes represent a relationship between the genes

    Number of genes identified in each module. In total, there were 28 modules. The gray module contains 59 genes that could not be assigned to any module and was excluded from downstream analysis

    Functional and pathway enrichment analysis

    Out of the 27 modules generated, only 14 modules were found to be enriched for GO terms 12 were over-represented and 2 (blue and green modules) were under-represented for GO terms (Additional file 7: Table S3). Seven of the 27 modules were enriched following KEGG pathway enrichment analysis, from which 5 were over-represented and 2 (lightcyan and blue modules) were under-represented for KEGG pathway terms (Additional file 8: Table S4). The top enriched GO terms for the modules with over-represented GO terms highlight some functions of the module genes (Table 1). Of the 12 modules with over-represented GO terms, 4 modules were over-represented for KEGG pathway terms and 1 module (yellow module) was over-represented for a KEGG pathway term (endocytosis), but not GO terms (Table 1).

    Modules hub gene identification

    Highly connected genes in a module are referred to as intra-modular hub genes. These hub genes are considered functionally significant in the enriched functions of the modules. Following the hypothesis that higher connectivity for a gene implies more importance in the module’s functional role, genes with the highest connectivity in the 27 modules were determined and considered to be the hub genes (Additional file 9: Table S5). Hub genes for the 12 modules with over-represented GO terms are described in Table 2.

    3′ UTR motif prediction based on gene co-expression modules

    Genes in a given module are hypothesized to be co-regulated as they are assumed to have similar functions. Consequently, their cis-regulatory element should be similar. Following this hypothesis, ten statistically significant RNA motifs, each over-represented in different gene modules, were identified using FIRE (Fig. 4a).

    Prediction of regulatory elements in the 3′ untranslated regions (UTR) based on gene co-expression modules. a Predicted motifs for the gene modules are shown. Columns represent gene modules, while rows represent the predicted motifs with consensus sequence on the right side. Over-representation of a motif for a given gene module is indicated by yellow color with significant over-representation highlighted by red frames. Blue color map and frames indicate under-representation. b Motif pairs co-occurring in the 3′ UTR are shown in the heatmap where each row and each column correspond to a predicted motif. Light colors indicate the presence of another motif within the same 3′ UTR while dark colors indicate that the motifs are absent in the same 3′ UTR. “+” indicates significant spatial co-localization between pairs of motifs


    Qo'shimcha fayl 1: rasm S1.

    OCCs present fluctuations in histone modifications. A. Heatmap of PC1 values for stable compartments from the three independent Hi-C biological replicates and B, the merged Hi-C biological replicates. C. PC1 eigenvector correlations between every pair of timepoints (Kruskal-Wallis rank sum test p-value < 2e-16). D. Proportion of OCCs and constant compartments in the mouse genome. E. Barplot of the frequency of the different OCCs categories with compartments switching at different times of the 24 hours. For example AABA refers to OCCs with compartment assignment A at ZT0, A at ZT6, B at ZT12 and A at ZT18. F. Chromatin features (H3Kme4 and H3Kme1) at OCCs across time points (AABB, ABBB and ABAB OCCs are shown) (*** all p-values < 0.001 except for the H3K4me1 AABB, one way ANOVA and Tukey post hoc test).

    Additional file 2: Figure S2.

    Total RNA-seq analysis at four timepoints during the circadian cycle. A. Spearman correlation analysis of the four biological replicates from ZT0 and ZT12 (r ≥ 0.85). B. Heat map of the relative transcription (Z scores) of 1,257 oscillating genes sorted by oscillation phase. C. Individual expression profiles and genome browser tracks showing examples of the RNA-seq signal for Arntl, Per1, Nr1d1, Cry1, Ppp1r3c va Gsk3a oscillating genes (Fragments Per Kilobase of transcript per Million mapped reads, FPKM) (n=4, q-value <0.01). D. GO analysis for the detected oscillating genes. Significantly enriched categories are shown. E. KEGG analysis for detected oscillating genes. Significantly enriched categories are shown. F. Additional individual transcriptional profiles from the RNA-seq for Rorc, Soat, Npas2, Cry2, Per2, Per3 circadian genes. G. RT-qPCR validation for candidate circadian genes both at mRNA and pre-mRNA level (p-values < 0.0001, one-way ANOVA test).

    Additional file 3: Figure S3.

    Expression profiles of the circadian genes displayed along the paper. RNA-seq signal tracks for circadian genes shown across the paper for the four timepoints during the circadian cycle. Arntl, Npas2, Cgn, Nr1d1, Dhrs3, Nr1d2, Per2, Ppp1r3c, Tef, Rnf125, Rorc va Aco2 circadian gene expression profiles are presented.

    Additional file 4: Figure S4.

    TAD structure and CTCF binding is preserved during the 24 hours. A. TADs overlap between time points. B. TADs size distribution at all time points. C. 50kb resolution Median Observed/Expected Hi-C signal around 1000 randomly selected TADs from ZT6, 12 and 18 plotted on the indicated time points. TADs were scaled to fit the five central bins. D. CTCF ChIP-seq motif analysis and peak overlap between ZT0 and 12. Genomic tracks of CTCF ChIP-seq signal at example regions harbouring circadian genes. E. Above, the same metaplots as in C but for 1000 randomly CTCF peaks found at ZT12 plotted using ZT12 and ZT0 Hi-C contacts. Below, metaplot using CTCF peaks from mESC and plotted using liver ZT0 and 12 Hi-C contacts. CTCF peaks are at the central bin of the metaplot. F. TAD and cTAD size comparison (p-value < 2.2e-16, Wilcoxon rank sum test).

    Additional file 5: Figure S5.

    Promoter-Promoter networks in the mouse liver over a circadian cycle. A. Partial view of a virtual 4C from the Arntl gene promoter using the Hi-C and P-CHi-C raw valid pairs. Histograms of read counts per restriction fragment around the bait region corresponding to the captured promoter are shown. B. Number of total read counts comparing Hi-C and P-CHi-C recovered using the Arntl1 gene promoter as bait on a virtual 4C (restriction fragments with at least 5 reads in the P-CHi-C experiment where used) (p-value < 0.0001, Wilcoxon ranked test). C. Promoter-promoter contact network at ZT0. Each color represents a chromosome. Nodes with degree=1 are not included for simplicity. D. The four largest promoter-promoter interaction clusters of the network at the different time points during the day. E. Significantly enriched GO categories for the genes on the most prominent promoter-promoter clusters shown in D.

    Additional file 6: Figure S6.

    Circadian gene promoter-promoter interactions. A. Promoter-promoter contact network at ZT0 with the circadian genes marked in blue. B. Above, number of edges (interactions) between circadian gene promoters at ZT0, 6, 12 and 18 hours of the day (blue line) compared to a random set of non circadian promoters. Below, z-score for circadian gene promoter contacts compared to the random sampling. C. Quantification of the read counts supporting all circadian gene promoter-promoter interactions compared to a random set of non circadian promoter-promoter interactions (*** p-value < 0.001, Mann Whitney test) D. Transcriptional phase distributions of circadian promoters in contact with diurnal or nocturnal circadian promoters (all p-values < 0.0001, Wilcoxon signed rank test) for our circadian intronic gene set. E. The same as in D for the circadian gene set detected through GRO-seq (Fang et al., 2014) (all p-values < 0.0001, Wilcoxon signed rank test) F. Virtual 4C landscape for the Tef circadian gene promoter from P-CHi-C data at all time points during the day. The acrophase of Tef is written next to the gene name. Expression profiles for both genes can be found in Figure S3. Genomic tracks show significant contacts as arcs and chromatin features including liver H3K4me3, H4K4me1, H3K27ac, DNAseI, eRNAs and TADs. Tef gene promoter contacts Aco2 gene promoter both with acrophase at ZT12.

    Additional file 7: Figure S7.

    Core clock gene promoter vs output circadian genes interaction landscapes.A-D. Virtual 4C for Rorc, Npas2, Nr1d2 va Per2, core clock circadian gene promoters from P-CHi-C data at all time points during the day. The Rorc circadian gene promoter contacts Cgn circadian gene promoter and both peak in transcription at ZT18. E-F Virtual 4C for Dhrs3 va Ppp1r3c output circadian genes in the liver. Acrophases are written next to the gene names. Genomic tracks show significant contacts as arcs and chromatin features including liver H3K4me3, H3K4me1, H3K27ac, DNAseI, eRNAs and TADs. Expression profiles for all genes can be found in Figure S3. The interaction profiles of core clock genes display less contacts that dynamically change over time. The two output gene contact profiles show more saturated contacts that are mostly constant during the 24 hours.

    Qo'shimcha fayl 8.

    Custom code. This file contains a summary of the custom code used in this work.


    Videoni tomosha qiling: Спирализация хромосом (Iyul 2022).


Izohlar:

  1. Tygonos

    Kechirim so'rayman, lekin menimcha, siz xatoni tan olasiz. Men buni muhokama qilishni taklif qilaman.

  2. Tolkis

    Men siz haqsiz deb o'ylayman. Men pozitsiyani himoya qila olaman. Menga kechqurun yozing.

  3. Kirkley

    Siz haqsiz, bunda nimadir bor. Ma'lumot uchun rahmat, ehtimol men ham sizga biror narsada yordam bera olamanmi?

  4. Jordan

    Juda yaxshi mavzu

  5. Teddie

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