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Jinsiy aloqaning ikki baravar narxi va r / K tanlash nazariyasi

Jinsiy aloqaning ikki baravar narxi va r / K tanlash nazariyasi



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Ushbu maqolada bir qator maqolalar keltiriladi (men ular orqali o'tmaganman) jinsiy aloqaning ikki baravar narxining ta'siri barqaror muhitda yoki K-tanlangan muhitda "kamaytirilgan". Unda shunday deyilgan:

[…] K-tanlangan turlarda sharmandali "ikki barobar" narxini pasaytirish yoki aniqrog'i osonroq muvozanatlash mumkin. "Erkaklarning narxi" ko'payish bilan bog'liq. Abugov (1985) hayot tarixi nazariyasi tamoyillariga ko'ra, K-seleksiyasi yordamida jinsiy aloqa ikki baravar qimmatga tushishi osonroq bo'lishi mumkin. Jinssiz ko'payishning ikki baravar hosildorlik afzalligi, K yoki r-tanlangan muhitda bo'lishidan qat'i nazar, har doim ikki karra fitnes afzalligi hisoblanadi. Biroq, omon qolish afzalligi r-tanloviga qaraganda K-tanlovida ko'proq qiymatga ega. Shunday qilib, agar jinsiy yo'l bilan olingan genotiplar omon qolish ustunligiga ega bo'lsa, K-tanlovi bo'yicha ikki baravar xarajatlarni muvozanatlash osonroq bo'ladi.

Menimcha, k-tanlash, k-tanlangan muhit va barqaror muhit bir xil turdagi muhitni (ko'proq yoki kamroq) tavsiflaydi. Agar bu sizga noto'g'ri tuyulsa, menga xabar bering. Bu erda r/K tanlash nazariyasi uchun wiki

Xuddi shu maqoladan K-tanlash quyidagicha aniqlanadi:

K-tanlovi sekinroq rivojlanishni, raqobatbardoshlikni, kechiktirilgan reproduktsiyani, omon qolish darajasini oshirishni, resurslar chegaralarini pasayishini, natijada "samaradorlik" ga (mahsuldorlikka emas) va atrof-muhitning o'tkazuvchanlik sig'imi yaqinida doimiy aholi soniga olib kelishi mumkin.

Bu menga juda g'alati tuyuladi. Iltimos, nima uchun barqaror muhitda jinsiy aloqaning ikki baravar narxi beqaror muhitga qaraganda pastroq ekanligini tushunishga yordam bera olasizmi?.


r/K tanlovi 1967 yilda MakArtur va Uilson tomonidan taklif qilinganidek, ma'lum bir muhitdan qanday turdagi turlar paydo bo'lishini bashorat qilishdan ko'ra ko'proq turlarning ko'payish strategiyasini tavsiflash uchun evristik xususiyatga ega bo'ldi. cite, rotiferlarning har xil muhitda r yoki ko'proq K tanlanganligini aniqlashga harakat qiladi.

Bu erda k-tanlash haqidagi fikr atamaning ta'riflaridan deyarli kelib chiqmaydi, shuning uchun u qog'ozda tushuntirilmagan.

R-tanlangan strategiyalarda ko'proq nasl tug'iladi, lekin har biriga kamroq sarmoya kiritiladi. Minglab mayda tuxum qo'yadigan tarakan haqida o'ylab ko'ring. Chiqaloqlarni o'z onasi yeyishi mumkin; ular juda arzon, tuxum qo'ygan hasharotlar tirik qolishidan tashvishlanmaydi. Haddan tashqari holatlarda, bu inkubatsiyalarning aksariyati ko'paymaydi, ular hatto etuklikka erishganlar uchun ozgina oziq-ovqat bo'lishi mumkin.

K-tanlangan strategiyalarda juda kam avlod tug'iladi. "Jinsiy aloqa xarajatlari" cheklanishidan tashqari, ular shu qadar katta mablag 'sarfladiki, ayol bir muncha vaqt tug'ilishni to'xtatishi mumkin. Masalan, emizikli sut emizuvchilar ko'plab qushlar singari tug'ish qobiliyatiga ega emas va mavsumiy juftlashmaydi; urg'ochilar reproduktsiyani o'chirib qo'yishadi, shunda ular bir yoki ikkita ishlab chiqarilgan naslning muvaffaqiyatiga e'tibor berishlari mumkin.

k-tanlovi, R-tanlovidan afzalroq, chunki ularning sarmoyalari ko'proq to'lanadi. Agar o'nta R-avloddan bittasi omon qolsa va k-tanlangan to'rtdan bir avlod omon qolsa, bu raqobatchi rotiferlar uchun k-tanlangan strategiya afzaldir.

Jinsiy aloqaning narxi shundan iboratki, uning aseksual ko'payishidan yarim baravar samarali, chunki erkaklar umuman ko'paymaydi - ular faqat urg'ochilar uchun genetik material beradi. Siz ushbu omildan mustaqil ravishda r/K tanlovi haqida bahslashishingiz mumkin, ammo maqolada k-tanlash shunchalik foydali bo'lishi mumkinligi, shuningdek, jinsiy tanlovga aseksual tanlovdan ustunlik berishi mumkinligi aytiladi. O'ylaymanki, aseksual ko'payish ham k-tanlanishi mumkin, ammo bu erda gap aytilganga o'xshaydi.

So'nggi bir necha o'n yilliklarda k/R ning ahamiyatini pasayishiga sabab shundaki, individual turlar o'z strategiyalarini o'zgartirishga moslasha olishlari aniqlandi.


Genom tahriridan foydalanib, jinsiy tanlov gipotezasini tekshirish

Biz Oryzias woworae medaka baliqlarida pektoral suyaklarning erkaklarga xos qizil rangiga asoslangan genni aniqladik. Genom tomonidan tahrir qilingan baliqlardan foydalanib, biz qizil erkaklar qizil bo'lmagan erkaklarga qaraganda ko'proq urg'ochi va yirtqichlarni jalb qilishini tekshirdik.

Ulashing

Havolani nusxalash

Shox shoxlari, qushqo'ng'izning pastki jag'lari va qizil tomoqlari: erkaklarning bunday ko'zga ko'rinadigan xususiyatlari qanday rivojlangan? Taxminan 150 yil oldin Charlz Darvin jinsiy tanlov nazariyasini taklif qilganidan beri (1), jinsiy tanlanish nazariyasini sinab ko'rish uchun ko'plab xulq -atvor tadqiqotlari o'tkazildi. Bundan farqli o'laroq, erkaklar bezaklari va qurollari evolyutsiyasining genetik asoslari haqida juda kam narsa ma'lum. Erkaklarning ko'zga ko'rinadigan xususiyatlarining evolyutsiyasi ostida qanday sababchi genlar va mutatsiyalar yotadi? Ansai va boshqalarda. 2021 yilda Tabiat bilan aloqa (2), biz bu savolni go'zal tropik medaka baliq (guruch baliq) yordamida hal qildik (1 -rasm).

1 -rasm. Oryzias woworae (yuqori, erkak pastki, urg'ochi). N. Xashimoto surati (Aqualife).

Men postdok bo'lganimda, umurtqa pog'onasidagi jinsiy dimorfik uzunlik va dorsal chayqalish xatti-harakatlarining o'zgarishi yopishqoqlikdagi neo-jinsiy xromosoma bilan bog'liqligini aniqladim [3]. Bu meni yangi jinsdagi xromosomalar evolyutsiyasi jinsiy dimorfizm evolyutsiyasi bilan bog'liq bo'lishi mumkin degan farazni keltirib chiqardi. 2011 yilda Yaponiya Milliy Genetika Institutida o'z laboratoriyam bo'lganida, men bu gipotezani boshqa turlar yordamida sinab ko'rishga qaror qildim.

Men kunlarimni Sietlda postdok sifatida ishlaganimda, doktor Kazunori Yamaxira Yaponiyaning Niigata universiteti dotsenti sifatida yapon medaka baliqlarining hayotiy xususiyatlarining kenglikdagi chizig'i ustida ishlagan (4). Biz birinchi marta Alyaskaning Fairbanks shahridagi Evolution 2005 da uchrashdik. O‘sha anjumanda Kazunorining go‘zal ishi menda katta taassurot qoldirdi. Besh yil o'tgach, men Yaponiyaga qaytdim va Kazunori bilan bog'lana boshladim (hozirda Ryukyus universiteti tropik biosfera tadqiqot markazida). Tropikadagi hayratlanarli biologik xilma-xillik sirlariga uzoq vaqt qiziqish bilan Kazunori tropik medaka baliqlari ustida ishlay boshladi. Garchi u tropikada biologik xilma -xillikning genetik asoslari bilan qiziqgan bo'lsa -da, o'sha paytda u genetik va genomik texnologiyalar bo'yicha tajribaga ega emas edi. Muhokama orqali biz tajribamiz bir-birini to'ldiruvchi ekanligini va Indoneziya medaka baliqlari jinsiy xromosoma evolyutsiyasi va jinsiy dimorfizm o'rtasidagi bog'liqlikni o'rganish uchun ajoyib model bo'lishi mumkinligini angladik. Kazunori go'zal medaka baliqni ko'rsatganda, Oryzias woworae (1 -rasm), men darhol bu go'zal baliqni yoqtirdim. Pektoral finning qizil rangi bu turning erkaklariga xosdir va boshqa hech kimga xos emas Oriziyalar baliqlarda shunday qizil pektoral qanotlari bor.

Kazunori bilan men bunday hamkorlik haqida gaplashayotganimizda, doktor Satoshi Ansai kunlarini Kyoto universitetida doktorant sifatida o'tkazdi va Yaponiyaning medaka baliqlariga yangi paydo bo'lgan genomni tahrir qilish texnologiyalarini qo'lladi (5). Satoshi medakadagi texnologiyani optimallashtirdi va ko'plab rivojlanish biologlari va nevrologlar bilan hamkorlik qildi. Satoshi nomzodlik dissertatsiyasini tugatganida, u genomni tahrir qilish texnologiyalarini ekologiya va tabiiy populyatsiyalar evolyutsiyasini o'rganishda hayajonli bo'lardi, deb o'yladi. Satoshi 2015 yilda men bilan bog'landi, Indoneziya medakalaridagi loyihadan juda xursand bo'ldi va mening laboratoriyamga qo'shilishga qaror qildi. O'shandan beri Satoshi, Kazunori va men 5 yildan beri hamkorlik qilyapmiz.

2 -rasm. Fotuno oe (Oryzias woworae ning yashash joyi).

Biz indoneziyalik tadqiqotchilar bilan hamkorlik qildik, ular orasida doktor Aleks Masengi, doktor Renni Hadiati, doktor Daniel Mokodongan, Bayu Kreshna Adhitya Sumarto va ularning ajoyib hamkasblari bor. Ning yashash joylariga tashrif buyurdik Oryzias woworae (2-rasm). Eng yorqin qizil populyatsiya ko'k nurli dominant buloqda yashaydi, bu erda qizil qanotlari ko'k fondan yaxshi farq qiladi (3-rasm).

Shakl 3. Qizil rang va ko'k suv o'rtasidagi farq.

Keyinchalik, Sulaveziy medakalar genomining mos yozuvlar ketma -ketligini tuzish uchun de novo genomlarini yig'ish bo'yicha mutaxassisi doktor Atsushi Toyoda bilan hamkorlik o'rnatdik. Doktor Koji Mochida, doktor Shingo Fujimoto va Yamahira laboratoriyasidagi hamkasblari gibrid baliqlarni ko'paytirish va fenotiplashdi, so'ngra Satoshi va doktor Atsushi Nagano genotiplashdi. Satoshi QTL cho'qqisini topdi va bitta kuchli nomzod genini aniqladi koloniyani ogohlantiruvchi omil 1 (csf1) avtosomada. Avvaliga men biroz xafa bo'ldim, chunki u jinsiy xromosomada emas edi, lekin biz jinsiy dikromatizm evolyutsiyasi asosida yotgan yaxshi nomzod genini aniqlashimiz juda hayajonli edi. csf1 zebrafishdagi pigment hujayralari rivojlanishida ishtirok etishi ma'lum.

Doktor Kiyoshi Naruzening laboratoriyasiga ko'chib o'tgandan so'ng, Satoshi genomni tahrir qilish bo'yicha o'z tajribasini qo'lladi Oryzias woworae va buni topdi csf1-nokaut baliqlari qizil rangga ega emas edi. Bu sababchi gen ekanligini aniq ko'rsatadi. Keyin, Satoshi jinsiy tanlash nazariyasi ta'kidlaganidek, urg'ochilar qizil erkaklarni qizil bo'lmagan (nokaut) erkaklarga afzal ko'radimi yoki yo'qligini tekshirish uchun juft tanlash tajribasini o'tkazdi (4-rasm). Javob ha edi. Keyinchalik, Satoshi yirtqichlarni jalb qilish tajribasini o'tkazdi. Jinsiy tanlash nazariyasi ko'pincha qizil erkaklar ham yirtqichlarni o'ziga jalb qiladi, degan xulosaga keladi. Bu gipotezadan farqli o'laroq, yirtqichlar qizil bo'lmagan (nokaut) erkaklarga ko'proq jalb qilingan. Bu natija avvaliga hayratlanarli bo'lib tuyuldi. Biroq, biz bir nechta oldingi tadqiqotlarni topdik, bu shuni ko'rsatadiki, ba'zi yirtqichlar kuchsizroq o'ljalarga hujum qilishadi, chunki bunday o'ljani osonroq ushlash mumkin. Agar qizil rang qochish qobiliyatini bildirsa, yirtqichlar qizil bo'lmagan erkaklarni tanlashi ajablanarli emas. Har qanday tajriba bu farazni isbotlamaguncha, bu hali ham farazdir.

Shakl 4. Qizil erkaklar urg'ochilarni o'ziga jalb qiladi, lekin yirtqichlarni jalb qilmaydi.

Bizning uzoq muddatli hamkorligimiz shuni ko'rsatdiki, genomlarni tahrirlash va genomlarni sekvensiyalash texnologiyalari integratsiyasi jinsiy tanlangan belgilar asosidagi sababchi genlarni aniqlashi va jinsiy tanlov nazariyalarini sinab ko'rish uchun yangi yo'l ochishi mumkin. Boshqa ko'plab javobsiz, ammo hayajonli savollar bor. Agar qizil rang urg'ochilarni jalb qilish va yirtqichlardan qochish uchun foydali bo'lsa, nega urg'ochilar qizil rangni ko'rsatmaydi? Ayollarning qizil bo'lishi uchun noma'lum xarajatlar bormi? Yana bir muhim savol - bu sababchi mutatsiya nima. Bu savollarga javob berish jinsiy dimorfik bezaklarning evolyutsion mexanizmlarini yaxshiroq tushunishga yordam beradi.


"Jinsiy rol" tushunchasi: umumiy nuqtai va baholash

"Jinsiy rollar" intuitiv ravishda stereotipik ayol va erkak jinsiy strategiyalari bilan bog'liq va biologiyada "jinsiy rol" atamasi ko'pincha juftlashish raqobati, turmush o'rtoq tanlash yoki ota-ona g'amxo'rligiga tegishli. "Jinsiy rolning o'zgarishi" populyatsiya yoki tur uchun odatiy tipologik naqsh me'yordan chetga chiqishini anglatadi va "jinsiy rolning o'zgarishi" ma'nosi ma'lum bir taksonda jinsga xos xatti-harakatlarning odatiy namunasiga qarab o'zgaradi. Biz "jinsiy rol" kontseptsiyasidan foydalanish bilan bog'liq bir nechta muammolarni aniqlaymiz. (1) Bu tipologik va jinslarning stereotipik umidlarini aks ettiradi. (2) "Jinsiy rol" atamasi doimiy o'zgaruvchanlikni faqat ikkita toifaga ajratadi, odatda xulq-atvori va morfologiyasi bo'yicha jinslar o'rtasidagi o'zaro bog'liqlikni va ekologik sharoitlar bilan bog'liq o'zgaruvchanlikni ajratadi. (3) "tabiatda ko'rinadigan jinsiy rol" kabi umumiy umumlashmalar tanlov ta'sir qilishi mumkin bo'lgan o'zgarishlarni yashiradi. (4) Jamiyatdagi "jinsiy rollar" ning umumiy ma'nosi (ya'ni "erkaklar va ayollarning xulq -atvori va hissiyotlari to'g'risida ijtimoiy va madaniy ta'riflar va e'tiqodlar") biologik "jinsiy rol" tushunchalariga zid, shuning uchun ikkalasini ham chalkashtirib yuboradi. jamiyatdagi ilmiy aloqa. Biz evolyutsion biologiyada "jinsiy rol" kontseptsiyasining to'g'riligini so'roq qilish bilan yakunlaymiz va "jinsiy rol" atamasini operatsion tavsiflar bilan almashtirishni tavsiya qilamiz.

Bu obuna tarkibini oldindan ko'rish, sizning muassasangiz orqali kirish.


Aloqalar

Chapel -Xilldagi Shimoliy Karolina universiteti biologiya bo'limi, Chapel -Xill, NC, AQSh

Brayan A. Lerch va Mariya R. Servedio

Bu muallifni PubMed Google Scholar -da ham qidirishingiz mumkin

Bu muallifni PubMed Google Scholar -da ham qidirishingiz mumkin

Hissalar

B.A.L. loyiha va optimallashtirish modellari haqida o'ylangan. B.A.L. va M.R.S. populyatsiyaning genetik modelini ishlab chiqdi. B.A.L. qo'lyozma ustidagi yozuvni M.R.S.ning rahbarligi bilan boshqargan.

Tegishli muallif


Materiallar va uslublar

Empirik tajribalar

Biz 1330 ta katta yoshli piyoz tripsi namunasini oldik (T. tabagi), 2009, 2010 va 2011 yil iyuldan sentyabrgacha Yaponiyaning Xokkaydo prefekturasidagi Kuriyama, Naganuma, Nanporo va Kitami shahridagi 32 piyoz yoki piyoz ekin maydonlaridan (namuna olish joylari xaritasi uchun S5 -rasmga qarang). Har bir ekin maydoniga aholi sifatida qaraldi. Tripslar uy o'simliklaridan oq plastik patnisga o'simlikni muloyimlik bilan silkitib, so'ngra aspirator yordamida yig'ib olindi. Namuna olingan barcha shaxslar tuxum qo'yuvchi va qanotlarning mavjudligi yoki yo'qligi asosida mikroskop ostida kattalar erkak, katta yoshli ayol va lichinkalarga ajratildi. Keyingi tajribalarda biz faqat kattalarni ishlatdik, chunki lichinkalarni jinsini ajratib bo'lmaydi. Keyinchalik, modifikatsiyalangan Chelex usuli 17 yordamida har bir kattalarning butun tanasidan genomik DNK chiqarildi. Quritilgan odamlar 200 mkl 5% Chelex eritmasida (Bio-Rad, Hercules, CA, AQSH 10 mM Tris-HCl, pH 8,0) va 5 mkl proteinaz K (TaKaRa, Otsu shahri, Shiga, Yaponiya 20 mg/)da maydalangan. ml), keyin 55 ° C da 12 soatdan ortiq 1,5 ml mikrosantrifüjli naychalarda inkübe qilinadi. Keyinchalik, aralashmalar proteinaz K ni inaktivatsiya qilish uchun 98 ° C da 10 daqiqa qaynatiladi. Shablon DNK Chelex qatlami yonidagi suvli qatlamdan olingan.

Har bir katta yoshli ayolning reproduktiv rejimi shtammga xos primerlar 16 bilan polimeraza zanjiri reaktsiyasi orqali aniqlandi. Primer to'plamiga shtamm tomonidan taqsimlangan ketma-ketlikni kodlaydigan bitta primer (TCOR, 5′-attgcgtaaattattcctaaaagtcca-3') va ikkita primer (jinsiy shtammga xos primer TCOS, 5′-aacagcTattctCcttcttttatctTCC-3′ astar) mavjud edi. 5′-gaacagtatatccacctttatcaacG-3 ′ katta harflari reproduktiv rejimlarga mos keladigan turli uzunlikdagi mtDNK bo'laklarini kuchaytiradigan (aseksual zo'riqish uchun 261 bp va jinsiy zo'riqish uchun 451 bp) kuchlanishga xos nukleotidlarni bildiradi. PCR-SSP uchun ishlatiladigan reaktsiya aralashmasining tarkibi quyidagicha edi: har bir 10 mkl reaktsiya aralashmasi 5 pmol konsensus primerini, har bir shtammga xos primerdan 2,5 pmol, 5 mkl 2 × MightyAmp Bufer, 0,1 mkl MightyAmp DNK polimerazasini (KaRa) o'z ichiga oladi. 1,25 U/ml), va 0,5 mkl shablon DNK. PCR-SSP 2720 termal tsikl yordamida amalga oshirildi (amaliy biosistemlar, Foster shahri, Kaliforniya, AQSh) quyidagi harorat davrlari bilan: 98 ° C da 2 minut boshlang'ich denaturatsiya, so'ngra 35 soniya denaturatsiya va tavlanish, 10 sek. 98 ° C va 60 ° C da 1 min, va 68 ° C da 1 min oxirgi uzaytirish bosqichi. PCR mahsulotlarining bo'lak uzunliklari etidiy bromidli binoni bo'lgan 100 mplik DNK zinapoyasidan (TaKaRa) 5 ml yordamida 1% agarozli jel elektroforezi orqali aniqlandi. Keyin har bir populyatsiyaning jinsi nisbati erkaklar sonini jinsiy individlar soniga bo'lish yo'li bilan hisoblab chiqildi va shunga o'xshash har bir populyatsiyaning jinsiy: jinssiz nisbati jinsiy individlar sonini kattalar umumiy soniga bo'lish yo'li bilan olingan.

Shtamm aniqlangandan so'ng, populyatsiyalar o'rtasidagi filogenetik munosabatlarni aniqlash uchun to'qqizta mikrosatellit lokusida tasodifiy tanlangan 20 tagacha jinsiy urg'ochi genotip qilindi. Ushbu mikroto'lqinli lokuslarni kuchaytirish uchun PCR uchun 2720 termal tsikli (Amaliy biosistemalar) ishlatilgan, u quyidagicha bajarilgan: 96 ° C da 2 minut boshlang'ich denaturatsiya, so'ngra 98 ° C da 5 soniya davomida 35 denatüratsiya davri, tavlanish. har bir primer juftiga xos bo'lgan haroratda 30 soniya davomida, 68 ° C da 1 minut uzaytirilishi va 68 ° C da 1 min. Ushbu mikrosatellit lokuslari uchun primer ketma-ketliklari va tavlanish harorati ilgari tasvirlangan 23 , unda biz jinsiy zo'riqishdagi mikrosatellit allellarining Mendel merosini tasdiqladik. Har 10 ml reaksiya aralashmasi 2 pmol primer, 5 ml 2 × MightyAmp buferi, 0,1 mkl MightyAmp DNK polimeraza (TaKaRa, Otsu, Yaponiya 1,25 U/mkl) va 1 mkl shablonli DNKdan iborat. PCR mahsulotining 1-ulik qismi CEQ-8000 genetik analizatorida (Bekman-Kulter) 0,5 mkl o'lchamdagi standart to'plam 400 (Bekman-Kulter, Fullerton, Kaliforniya, AQSh) bilan tandemda elektroforez qilindi. Allel chastotalari bo'yicha olingan ma'lumotlarga asoslanib, juft genetik masofalar (F.ST) 32 populyatsiya o'rtasida va har bir populyatsiya uchun Hardy-Weinberg muvozanatidan chetlanishlar Arlequin dasturi 3.5.1.2 24 yordamida hisoblab chiqilgan. Keyin, MEGA 5-versiya dasturi 25 yordamida juft genetik masofa matritsasidan qo'shni birlashtiruvchi daraxt qurilgan.

Jinsiy va jinsiy: aseksual nisbat o'rtasidagi korrelyatsion tahlildan filogenez ta'sirini olib tashlash uchun filogenetik jihatdan mustaqil kontrastlar ishlatilgan. Biz qo'shnilar bilan bog'langan daraxtda bir-birining ustiga chiqadigan novdalarsiz aholi juftlarini joylashtirdik. Shunday qilib, 32 populyatsiyadan 16 populyatsion juftlik olingan (Qo'shimcha rasm S1). Har bir populyatsiya juftligi uchun jinsiy nisbatlar va jinsiy: aseksual nisbatlar o'rtasidagi farqlar hisoblab chiqilgan. Bu usul filogeniya 22 ning har bir tarmog'idagi o'zgarish miqdorini ifodalovchi statistik mustaqil qiymatlarni beradi. Ushbu farqlardan foydalanib, biz jinsiy nisbatlar va jinsiy: aseksual nisbatlar o'rtasidagi evolyutsion munosabatlarni tahlil qildik.

Shtammlar orasidagi reproduktivlik darajasidagi farqlarni o'rganish uchun biz Nanporo, Xokkaydo prefekturasi, Yaponiyadagi beshta ekin maydonlarining har biridan qo'shimcha 50 ta katta yoshli urg'ochilardan namuna oldik. Bu urg'ochilar alohida-alohida 50 ml lik santrifüj naychalarida 5 ml kalıplanmış gips bilan 25 ° C kamerada uzoq kunlik sharoitda (14 L: 10D) o'stirildi. Oziq-ovqat manbai va tuxum qo'yish substrati sifatida har bir ayol uchun terisi olib tashlangan sarimsoq chinnigullari berildi. 3 kundan keyin biz katta yoshli urg'ochilarni santrifüj naychalaridan olib tashladik va yuqorida tavsiflangan usul yordamida ularning reproduktiv usullarini baholadik. Bu vaqtda vafot etgan urg'ochilar quyidagi tahlildan chiqarildi. O'stirish boshlanganidan keyin 20-kuni biz santrifüj naychalari ichidagi barcha shaxslardan namuna oldik va hisobladik. Tajriba tugagach, biz har bir reproduktiv kattalarning jinsini mikroskop ostida tekshirdik.

Barcha statistika R kompyuter dasturi, 3.1.0 versiyasi yordamida amalga oshirildi. Proportional ma'lumotlar uchun (jinsiy: aseksual nisbatlar va jinslar nisbati), biz "glm" funktsiyasidagi kvazi-binomial logit havolasi yordamida umumlashtirilgan chiziqli modellardan foydalandik va "mashina" paketidagi "Anova" funktsiyasidan foydalanib statistik qiymatlarni oldik. Boshqa ma'lumotlar uchun (filogenetik jihatdan mustaqil kontrast tahlilidagi farqlar, nasllar va qoldiqlar soni) biz "lm" funktsiyasi va "Anova" funksiyasidan foydalangan holda umumiy chiziqli modeldan foydalandik.

Simulyatsiya

Jinsiy populyatsiyalarda ayollarga nisbatan noaniq jinsiy nisbatlarning rivojlanishi ehtimolini baholash T. tabaci ularning aseksual hamkasblari bilan raqobat qilish uchun biz haploid populyatsiyani, shu jumladan jinsiy erkaklar va urg'ochilarni va aseksual urg'ochilarni, 10 000 ta yamoqlarda (subpopulatsiyalarda) diskret avlodlar bilan, har bir avlodda quyidagi hodisalar quyidagi tartibda sodir bo'lgan individual asoslangan modelni qurdik. : juftlashtirish, tarqatish, pestitsidlarni qo'llash va ko'paytirish.

Juftlanish yamoq ichidagi jinsiy shaxslar orasida tasodifiy sodir bo'lgan (erkaklar bir necha marta, jinsiy urg'ochilar esa bir marta juftlashgan) va aseksual urg'ochilar uchun o'tkazib yuborilgan, shundan so'ng barcha erkaklar o'lib, urg'ochilar tug'ilish joyida qolishgan yoki tarqalib ketishgan. tarqalish tezligi d, genetik jihatdan bitta lokus bilan aniqlangan (0 & lt d & lt 1). Tarqalish ehtimoli bo'yicha muvaffaqiyatli hisoblangan p = 0,02, 0,05 yoki 0,1, va agar u muvaffaqiyatsiz bo'lsa, urg'ochilar vafot etdi. Barcha yamoqlardan tasodifiy maqsadli yamoq tanlandi. Tarqalganidan so'ng, pestitsidlar yamalardagi barcha odamlarga, agar odamlar soni ma'lum bir chegara qiymatidan katta bo'lsa, qo'llanilgan (t = 10, 20 yoki 40). Keyinchalik, aseksual urg'ochilar mutatsiyaga uchragan hollar bundan mustasno, genetik jihatdan bir xil qizlarni tug'ishdi, jinsiy yo'l bilan tug'ilgan avlodlar esa har bir joyda ota yoki otadan bitta allelni meros qilib olishdi. Jinsiy ko'payish uchun jins nisbati (nasldagi erkaklarning nisbati). m) ikkita strategiya bo'yicha aniqlangan: birinchisi LMC nazariyasi 21 ga asoslangan va (n−1)/2n (n yamoqdagi jinsiy urg'ochilar sonini ko'rsatadi), ikkinchisi esa lokusning genetik qiymatiga asoslangan g (0 & lt g & lt 1). Jinsiy urg'ochilarning bu ikkita strategiyasi boshqa joy bilan almashtirildi (L = 0 yoki 1, agar qiymat nol bo'lsa, ayol o'zining genetik qiymatidan foydalanadi, agar qiymat bitta bo'lsa, u LMC nazariyasining bashoratiga amal qiladi). Biz tasodifiy mutatsiyalarni har bir avlod uchun doimiy ehtimollik bilan qabul qildik (ya'ni 0,001). Agar mutatsiya sodir bo'lsa, gen dispersiya tezligiga mos keladigan joyda 0 dan 1 gacha bo'lgan tasodifiy qiymat bilan almashtirildi. d va erkaklar nisbati mva jinsi nisbati strategiyasini o'zgartirishga mos keladigan joy uchun 0 yoki 1 qiymati ishlatilgan L. Qayta tug'ilgandan so'ng, barcha kattalar o'ldi va keyingi avlod boshlandi.

Biz simulyatsiyalarni barcha lokuslar uchun tasodifiy genetik qiymatlarga ega 10 000 jinsiy shaxslar bilan boshladik. 1000 avloddan keyin 1000 aseksual shaxslar tasodifiy tanlangan yamoqlarga kiritildi. Biz uchta parametr ta'sirini baholadik: (i) har bir ayolga nasl soniga qarab jinsiy ko'payishning foydasi (jinsiy shaxslar uchun 20 ta va aseksual shaxslar uchun 15 yoki 20 ta) (iimuvaffaqiyatning tarqalish ehtimoli (p = 0,02, 0,05 yoki 0,1) va (iiipestitsidlarni qo'llash chegarasi (t = 10, 20 yoki 40). 18 ta parametr to'plamining har biri uchun biz 100 ta simulyatsiyani o'tkazdik va jinsiy yoki aseksual shtamm yo'qolguncha yoki 10 000 avlod simulyatsiya qilinmaguncha ko'payish va juftlashish hodisalari orasidagi populyatsiya dinamikasi va gen chastotalarini qayd etdik. Biz barcha simulyatsiyalarni Visual C++ 2012 yordamida amalga oshirdik va simulyatsiya kodini qo'shimcha eslatma sifatida onlayn tarzda taqdim etdik.


Individual tanlov ostida ikki ota-ona jinsiy aloqa narxi

Anizogamik biparental jinsning kamchiliklari erkaklarni ajratish yoki meioz xarajatlari bilan bog'liqligini aniqlash uchun ishlab chiqilgan evolyutsion barqaror strategiyalar modellari keltirilgan. Natijalar shuni ko'rsatadiki, (1) biparental jinsiy aloqa xarajatlari gen almashinuvi bilan bog'liq bo'lib, keksistual odamlarda kleistogam bo'lmagan partenogenetik tuxum hujayralari ulushini oshiradi va (2) biparental jinsning narxi erkaklarning ajratishidan kelib chiqadi, bu mutatsiyalar somatik ko'payishni oshiradi. ikkilamchi ayollarda qisman patenogenezni kuchaytiruvchi kekseksual shaxslar va mutatsiyalar. Umuman olganda, ikki ota-onalik jinsining narxi, agar bir ota-onadan ko'payishni kuchaytiradigan mutatsiyalar erkaklar taqsimlash qaroridan oldin sodir bo'lgan voqealarga ta'sir qilganda, erkaklarning taqsimlanishi bilan bog'liq, va ikki ota-ona jinsining narxi bir ota-onaning ko'payishiga olib keladigan mutatsiyalar natijasida gen almashinuvi bilan bog'liq, deb taxmin qilinadi. ko'payish erkaklarni ajratish qaroridan keyin sodir bo'ladigan hodisalarga ta'sir qiladi.


Sharh

Erkaklar va urg'ochilar o'rtasidagi aniq farq zigotaga investitsiya qilishiga asoslanadi: urg'ochilar sitoplazmaning asosiy qismini katta tuxum orqali ta'minlaydi, erkaklar esa mayda sperma yoki gulchang donasi bilan deyarli hech qanday hissa qo'shmaydi. Ichki o'g'itlash va/yoki parvarish bilan shug'ullanadigan turlarda, investitsiyalarning bu assimetriyasi naslning keyingi rivojlanish bosqichlariga ham cho'zilishi mumkin, chunki erkaklar ko'pincha o'z hissasini qo'shmaydi yoki hech narsa qo'shmaydi. Jon Meynard-Smitning ta'kidlashicha, investitsiyalardagi bu farq jinsiy ko'payish aseksualga qaraganda ikki baravar qimmatga tushishini bildiradi [1]. O'tkir jinsiy populyatsiyada barqaror jinsiy aloqa nisbati 50:50 ni tashkil qiladi, shuning uchun o'rtacha hisobda odamlar resurslarning 50 foizini erkaklarga sarflaydilar, ular resurslarni naslga aylantiradilar. Ikki alohida jinsli jinsiy populyatsiyada aseksualizmni keltirib chiqaradigan mutatsiya har bir avlodda dastlab ikki baravar ko'payadi, chunki hamma teng bo'lsa ham, aseksualizm resurslarni avlodlarga aylantirishda ikki baravar samaralidir.

Yangi tadqiqot BMC biologiyasi Termit turlari erkaklardan butunlay voz kechishi mumkinligini ko'rsatadi, bu Meynard-Smitning aseksual variantlar jinsiy qarindoshlarga nisbatan qisqa muddatli foyda keltirishi mumkinligi haqidagi g'oyasiga mos keladi. Turlarning ba'zi populyatsiyalarining malikalari Glyptotermes nakajimai Erkaklar hech qanday genetik hissa qo'shmasdan ko'payadilar, nafaqat yangi malika tug'diradilar, balki steril ishchilar va askarlar tug'adilar. Olti populyatsiyadan 37 ta koloniyaning askarlari, ishchilari va reproduktivlariga tegishli bo'lgan 4200 dan ortiq odamlarni ajratish bitta erkakni aniqlamadi. Xuddi shu turdagi boshqa to'rtta populyatsiyaning koloniyalarida erkak va urg'ochi jinslar, reproduktiv, ishchi va askar kastalari uchun taxminan teng miqdorda bo'lgan. Erkaklarning yo'qligini qo'shimcha qo'llab-quvvatlash uchun, oltita urg'ochi ayollarning spermatekalari-sperma saqlash organlari-hech qanday spermatozoid tashimagan, qolgan populyatsiyalar malika spermatozoidlari esa sperma bilan to'lgan. Erkaklarda urug'lantirilmasdan ko'payishning aniq mexanizmi noma'lum, yoki o'z-o'zini urug'lantirishning qandaydir shakli (gametalarning ko'payishi yoki gametalarning sintezi orqali automiksis) yoki tuxumlar mitoz orqali hosil bo'ladigan sof aseksual ko'payish (apomiksis). Aseksual populyatsiyalarning xromosoma soni notekis bo'lganligi sababli, apomiksis eng maqbuldir.

Butun urg'ochi jamiyatlarni ishlab chiqargan holda, bu termitning koloniyalari gipermenan hasharotlar, chumolilar, ijtimoiy ari va asalarilar koloniyalariga o'xshaydi, bu erda steril yordamchilar faqat urg'ochilar. Uzoq vaqtdan buyon bu jinsga moyillik ularning o'ziga xos jinsini aniqlash natijasidir, deb ishonilgan. Hymenopteradagi jinsiy aloqa ploidiya bilan belgilanadi: urug'lanmagan, haploid, tuxum erkak bo'lib, urug'langan, diploid, tuxum urg'ochi bo'lib rivojlanadi. Gaplo-diploid jinsini aniqlash qarindoshlik uchun qiziqarli ta'sir ko'rsatadi (r) turli koloniya a'zolari orasida (1a -rasm). Bitta erkak bilan juftlashgan bitta malika tomonidan tashkil etilgan koloniyada qizlar o'z opa-singillari bilan ¾ ga yaqin qarindoshlikka ega, chunki ularning barchasi genomining yarmi haploid ota orqali va qo'shimcha ravishda o'rtacha to'rtdan bir qismi diploid onasi orqali umumiydir. Bundan farqli o'laroq, ularning o'z avlodlari bilan bog'liqligi atigi ½. Bill Hamilton tomonidan taklif qilingan haplo-diploidiya gipotezasiga ko'ra, qarindoshlikdagi bu farq urg'ochi ayollarni ishchi bo'lishga moyil qiladi, chunki ular onalariga opa-singillarini o'zlari yangi malika etishtirishdan ko'ra yangi malika bo'lishlariga yordam berish orqali o'zlarining inklyuziv jismoniy tayyorgarligini oshirishlari mumkin. ].

Chumolilarning standart hayot aylanishi (a) va termitlar (b) va malika va erkaklarning reproduktiv manfaatlari o'rtasidagi ziddiyatlar tufayli og'ishlar. Ajdodlarning genomlari nasldagi ranglarda ko'rsatilgan (Devid Nash tomonidan tayyorlangan eskizdan ruxsat olgan holda). a Chumolilar haplo-diploid hayot tsikliga ega, bu erda urug'lanmagan tuxum erkak bo'lib, urug'langan tuxum esa ishchi yoki urg'ochi alat bo'ladi. Chumolilar jamiyatidagi barcha ishchilar ayollardir. Ba'zi chumolilarda malikalar alat hosil qilish uchun partenogenetik ko'payishadi, lekin jinsiy yo'l bilan ishchi hosil qilish uchun erkaklarda parazitlik qiladi [5]. Yana bir og'ishda, malika va erkak har birining o'ziga xos urg'ochi va erkak alatesini jinsiy yo'l bilan ko'payish yo'li bilan, lekin ishchilar jinsiy ko'payish yo'li bilan ishlab chiqaradilar [6]. Nihoyat, ba'zi chumoli turlari majburiy ravishda aseksual bo'lib qoldi, bu erda ham ishchilar, ham yangi malikalar erkaklar hissasisiz ishlab chiqariladi [7]. b Chumolilardan farqli o'laroq, termitlar diploid ijtimoiy hasharotlardir. "Standart" hayot tsiklida bitta malika va qirol koloniya topib, jinsiy ko'payish orqali steril yordamchilar (ishchilar va askarlar) va unumdor alatlar ishlab chiqaradilar. Ba'zi turlarda almashinadigan ko'payish sodir bo'ladi, bu erda asosiy malika va qirolni o'z avlodlari almashtirishi mumkin [8]. Ba'zi turlarda malika jinssiz ko'payish yo'li bilan o'rnini bosuvchi malika hosil qilishi mumkin [9]. Nihoyat, turning ba'zi populyatsiyalari Glyptotermlar aleks va ishchilarni aseksual ko'payish yo'li bilan tashkil etuvchi barcha ayol jamiyatlari bor [2].

Biroq, haplo-diploid jinsini aniqlashning teskari tomoni shundaki, opa-singillar birodarlari bilan unchalik bog'liq emas.r = ¼) o'z o'g'illariga qaraganda (r = ½). Keyinchalik ma'lum bo'ldiki, bu Hymenoptera'ning barcha ayollar jamiyatlarini haplo-diploidiya gipotezasi bilan izohlab bo'lmaydi, chunki urg'ochi va opa-singillar o'rtasidagi o'rtacha qarindoshlik ½, ya'ni o'z avlodlari bilan bog'liqlikka teng. Buning o'rniga, yaqinda o'tkazilgan tahlillar yordamchilarning jinsini evosotsiallikni qo'llab-quvvatlovchi ekologik omillarning o'zgarishi bilan izohlash mumkin degan gipotezani qo'llab-quvvatladi [4]. Bu g'oyaga ko'ra, agar yordamchilarning asosiy vazifasi nasl tug'ish bo'lsa, biz yordamchilarni ota-ona qaramog'ini ta'minlaydigan jinsi yoki jinsidan olishini kutgan bo'lardik. Ijtimoiy Hymenoptera yordamchilarining asl vazifasi, albatta, naslni tarbiyalash edi. Bundan farqli o'laroq, termitlarda yordamchilarning boshida koloniya mudofaasi kabi bir nechta vazifalar bo'lgan bo'lishi mumkin. Termitlarning ajdodlari oziq-ovqat bilan ta'minlaydigan yog'och tanasini egallaganligi sababli, ular o'zlarining oziq-ovqatlari ichida yashashgan, bu esa raqobatchilardan himoyalanishga arziydigan qimmatli manba bo'lgan. Ikkala jins ham mudofaa vazifalari uchun oldindan moslashtirilmaganligi sababli, yordamchilar ikkala jinsdan ham jalb qilinishini kutamiz. Bu nima uchun termit turlarining ko'pchiligidagi yordamchi kastalar odatda erkak va urg'ochi jinslarning aralashmasidan iboratligini tushuntirishi mumkin.

Garchi opa-singillar o'rtasidagi yuqori qarindoshlik endi Hymenopteran turlarining ishchilarining jinsini tushuntirmaydi, deb hisoblansa ham, qarindoshlarni tanlash nazariyasi ijtimoiy hasharotlar jamiyatida uchraydigan ekstremal altruizm evolyutsiyasini tushuntirib beradi. Urug'li bolalarni tug'ilishiga yordam berib, bepushtlar genetik jihatdan bog'liq bo'lgan odamlarda mavjud bo'lgan genlar orqali ularning inklyuziv fitnesini oshirishi mumkin. Shu bilan birga, koloniya a'zolari o'rtasidagi munosabatlardagi farqlar koloniyaning turli a'zolari o'rtasidagi ziddiyatlarga boy zamin yaratadi. Qarindoshlar to'qnashuvi chumolilarda eng ko'p o'rganilgan (1a-rasm). Yaqinda bunday to'qnashuvlarning ajoyib natijalari tasvirlangan. Chumolilar turida Kataglif kursoriErkaklar va ishchilar, o'z navbatida, urug'lanmagan va urug'lanmagan tuxumlardan normal jinsiy ko'payish yo'li bilan ishlab chiqariladi, lekin malika o'zlarini klon qilib, yangi malika tug'adilar [5]. Shunday qilib, malikalar erkaklarda parazitlik qiladi, chunki erkaklar keyingi avlod reproduktiviga hech qanday genetik materialni qo'shmaydi, faqat ishchilarga. Boshqa holatlarda esa, erkak va urg'ochi o'rtasidagi genlarni uzatishda ziddiyat natija ko'rsatdi. Bir nechta chumoli turlarida ishchilar jinsiy yo'l bilan, lekin urg'ochi va erkak jinsiy yo'l bilan jinsiy yo'l bilan ishlab chiqariladi. Bunday hollarda, erkaklar urug'lantirilgan tuxumdan ona genomini chiqarib tashlashga muvaffaq bo'lishadi va shu bilan o'zlarini klonik tarzda ko'paytiradilar [6]. Qizig'i shundaki, bunday hollarda erkak va urg'ochi genomlari faqat ishchilarda birlashtirilgan evolyutsion jihatdan butunlay ajralib chiqqan nasllarni ifodalaydi. Finally, like the newly discovered termite populations, some ant species have also disposed of males completely, and reproduce asexually [7].

In termites, kin conflicts have been studied less extensively (Fig. 1b). In some species, one or more offspring can replace a primary reproductive that has died and become a replacement or secondary reproductive. Replacement reproduction results in inbreeding and can happen repeatedly in a single colony. This was once believed to be important for the evolution of reproductive altruism in diploid organisms, since inbreeding increases relatedness among colony members [8]. In 2009, Matsuura and co-workers discovered that in some termite species, secondary queens are produced by parthenogenesis of the primary queen, so-called asexual queen succession (AQS) [9]. By cloning herself, the queen can extend her (genetic) lifespan. An additional consequence is that the queen can increase her genetic contribution to offspring beyond the 50% that results from normal reproduction. The reason is that the primary king cannot produce secondary kings by parthenogenetic reproduction, but only by mating with the queen.

The one-sided, mother–son inbreeding which can result from mating between the cloned queen and the secondary king in long-lived colonies implies that colony members are then related by ¾ to the primary queen, and only by ¼ to the primary king [10] (Fig. 2). This implies that, from an inclusive-fitness perspective, female reproductives are more valuable for colony members, both male and female, than male reproductives. Kin-selection theory therefore predicts that workers should favour a female-biased sex ratio of the alates, which is supported by empirical evidence for several species with AQS, and, as expected, not for species without AQS [9]. Here, I want to propose another possible corollary of this difference in relatedness between helpers and the primary king and relatedness between helpers and the primary queen. Since sex determination in termites is chromosomally based on an XY system, random segregation of X and Y chromosomes will lead to an equal sex ratio. However, since caste of an offspring is determined by environmental factors influenced by helpers, helpers can influence the sex ratio of the alates. Since helpers, irrespective of their sex, all have an interest in a more female-biased sex ratio of the alates, a direct consequence of raising more female offspring as alates may be that a larger proportion of the remaining offspring that become helpers are male. A testable prediction, therefore, is that species with AQS, in conjunction with a more female-biased sex ratio of the alates, have a more male-biased sex ratio of the helper castes. Consistent with this prediction, the species Reticulitermes virginicus, which has AQS and the most strongly female-biased alate sex ratios, shows a significantly male-biased worker sex ratio, although the sex ratio of soldiers is female biased (Matsuura, personal communication). Clearly, more research is needed to test this hypothesis.

The consequences of replacement reproduction for relatedness of colony members to the primary queen and king. a ‘Standard’ replacement reproduction, where secondary reproductives are both produced sexually by the primary reproductives. b Replacement reproduction where the secondary queen is formed by asexual queen succession, so that the primary queen extends her genetic life span, but the secondary king is formed by sexual reproduction of the primary king and queen

The increased tendency for the helper castes to become male biased for species with AQS may constrain the evolution of all-female asexual reproduction of such species, since they rely on males as a work force. It therefore may make sense that the all-female societies of G. nakajimai discovered now [2] belong to a family where AQS is not known (Kalotermitidae). It is ironic that in the group where males contribute more to raising the offspring than any other group of social insects, females of some populations have gotten rid of males. Yet, the benefit of saving on the twofold cost of sex remains: since males contribute so little to the zygote, diverting resources away from males towards females can be selected for. In G. nakajimai the more uniform morphology of the soldier caste appears to provide an additional advantage in colony defence, allowing asexual populations to maintain a smaller soldier force [2].

The rarity of purely asexual reproduction and the empirical finding that asexual lineages generally represent terminal branches in the tree of life suggest that asexuality is doomed to death on the long term. Nevertheless, the split between the sampled asexual and sexual lineages in Glyptotermes nakajimai is estimated to have occurred 14 million years ago [2]. However, as acknowledged by the authors, this time estimate may not indicate the split of asexuality from sexual ancestors, but only the maximum divergence time. Finding populations intermediate in divergence from those two clusters of lineages could give a more realistic estimation of the age of asexuality in this termite species. Time will thus have to tell how long these colonies of emancipated females have managed to survive without males.


Nashrlar

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“Species and stock identification of prey consumed by endangered southern resident killer whales in their summer range“ MB Hanson, RW Baird, JKB Ford, J Hempelmann-Halos, DM Van Doornik, JR Candy, CK Emmons, GS Schorr, B Gisborne, KL Ayers, SK Wasser, KC Balcomb, K Balcomb-Bartok, JG Sneva, MJ Ford

2010 Conservation Biology, 25(1): 154-162

“Effectiveness of scat-detection dogs in determining species presence in a tropical savanna landscape“ C Vynne, JR Skalski, RB Machado, MJ Groom, ATA Jacomo, J Marinho-Filho, MB Ramos Neto, C Pomilla, L Silveira, H Smith, SK Wasser

2010 Ilm, 328: 1633-1635

“Response — Consequences of Legal Ivory Trade“ SK Wasser, K Nowak, J Poole, J Hart, R Beyers, P Lee, K Lindsay, G Brown, P Granli, A Dobson

2010 Fan, 327: 1331-1332

“Elephants, Ivory, and Trade“ SK Wasser, J Poole, P Lee, K Lindsay, A Dobson, J Hart, I Douglas-Hamilton, G Wittemeyer, P Granli, B Morgan, J Gunn, S Alberts, R Beyers, P Chiyo, H Croze, R Estes, K Gobush, P Joram, A Kikoti, J Kingdon, L King, D Macdonald, C Moss, B Mutayoba, S Njumbi, P Omondi, K Nowak

2009 Ilmiy amerikalik, 68-76
2009 Journal of Zoo and Wildlife Medicine, 40(2): 382-384
2009 Animal Behaviour, 78: 1079-1086
2009 Journal of Wildlife Management, 73(7): 1233-1240

“Scent Matching Dogs Determine Number of Unique Individuals from Scat” SK Wasser, H Smith, L Madden, N Marks, C Vynne

2009 Molekulyar ekologiya, 18: 722-734

“Genetic Relatedness and Disrupted Social Structure in a Poached Population of African Elephants” KS Gobush, B Kerr, SK Wasser

2009 Conservation Biology, 22: 1590-1599.

“Long-Term Impacts of Poaching on Relatedness, Stress Physiology, and Reproductive Output of Adult Female African Elephants” KS Gobush, BM Mutayoba, SK Wasser

2008 Natural History, pp.48-53

“Lucky dogs: Dogs sniff out scat from endangered animals, trumping more technical tracking methods” SK Wasser

2008 Tabiatni muhofaza qilish biologiyasi, 22: 1065-1071
2007 Tabiat protokollari, 2: 2228-2232

“Isolation of DNA from small amounts of elephant ivory” C. Mailand, SK. Wasser

2007 Proceedings National Academy of Sciences, 104: 4228-4233

“Using DNA to track the origin of the largest ivory seizure since the 1989 trade ban” S Wasser, C Mailand, R Booth, B Mutayoba, E Kisamo, B Clark, M Stevens

2006 Journal of Cetacean Research and Management, 8(2):121-125

“Faecal sampling using detection dogs to study reproduction and health in North Atlantic right whales (Eubalaena glacialis)” R Rolland, P Hamilton, S Kraus, B Davenport, R Gillett, S Wasser

2006 African Journal of Biotechnology, 5: 1588-1593

“The potential of mitochondrial DNA markers and polymerase chain-reaction fragment length polymorphism for domestic and wild species identification” A Malisa, P Gwakisa, S Balthazary, S Wasser, B Mutayoba

2006 General and Comparative Endocrinology, 148: 260-272
2005 African Journal of Biotechnology, 4: 1269-1274
2005 Zoo Biology, 24: 403-417

“Longitudinal monitoring of fecal testosterone in male Malayan sun bears (Ursus malaynus)” H Hesterman, SK Wasser, JF Cockrem

2005 Annals of the New York Academy of Sciences, 1046: 109-137

“Noninvasive measures of reproductive function and disturbance in the barred owl, great horned owl, and northern spotted owl” SK Wasser, KE Hunt

2005 General and Comparative Endocrinology, 142: 308-317

“Assessing reproductive status of right whales (Eubalaena glacialis) using fecal hormone metabolites” RM Rolland, KE Hunt, SD Kraus, SK Wasser

2004 Proceedings National Academy of Sciences, 101: 14847-14852

“Assigning African elephant DNA to geographic region of origin. Applications to the ivory trade” SK Wasser, A. Shedlock, K. Comstock, E. Ostrander, B. Mutayoba, M. Stephens.

2004 Xulq-atvor ekologiyasi va sotsiobiologiya, 56: 328-337

“Infant handling and mortality in yellow baboons (Papio cynocephalus): evidence for female reproductive competition?” S Kleindorfer, SK Wasser

2004 Xulq-atvor ekologiyasi va sotsiobiologiya, 56: 338-345.

“Population trend alters the effects of maternal dominance rank on lifetime reproductive success in yellow baboons (Papio cynocephalus)” SK Wasser, GW Norton, S Kleindorfer, RJ Rhine

2004 Canadian Journal of Zoology, 82: 475-492
2004 Physiological and Biochemical Zoology, (matbuotda)

“Factors Associated With Fecal Glucocorticoids In Alaskan Brown Bears (Ursus arctos horribilis)” CG van der Ohe, SK Wasser, K. Hunt, C Servheen

2004 Physiology and Behavior, 80: 595-601

“Validation of a fecal glucocorticoid assay for Steller sea lions (Eumetopias jubatus)” KE Hunt, A Trites, SK Wasser

2003 Physiological and Biochemical Zoology, 76: 918-928

“Effect of long-term preservation methods on fecal glucocorticoid concentrations of grizzly bear and African elephant” KE Hunt, SK Wasser

2003 General and Comparative Endocrinology, 134: 18-25

“Noninvasive reproductive steroid hormone estimates from fecal samples of captive female sea otters (Enhydra lutris)” S Larson, CJ Casson, SK Wasser

2003 Tabiatni muhofaza qilish biologiyasi, 17: 1-4

“Amplifying nuclear and mitochondrial DNA from African Elephant Ivory: A tool for monitoring the ivory trade” KE Comstock, EA Ostrander, SK Wasser

2002 Molecular Ecology, 11:2489-2498

“Patterns of molecular genetic variation among African elephant populations” KE Comstock, N Georgiadis, J Pecon-Slattery, AL Rocca, SJ O’Brien, SK Wasser

2002 Conservation Genetics, 3: 435-440

“An evaluation of long-term preservation methods for brown bear (Ursus arctos) faecal DNA samples” MA Murphy, LP Waits, KC Kendall, SK Wasser, JA Higbee, R Bogden

2002 Conservation Medicine: Ecological Health in Practice, pp 130-144

“Assessing stress and population genetics through non-invasive means” Aguire, AA., RS Ostfeld, GM Taber, C House, MC Pearl (eds.) SK Wasser, KE Hunt, CM Clarke

2001 Wildlife Society Bulletin, 29: 899-907

“Fecal glucocorticoid assays and the physiological stress response in elk” JJ Millspaugh, RJ Woods, KE Hunt, KJ Raedeke, GC Brundige, BE Washburn, SK Wasser

2001 Reproductive Ecology and Human Evolution, pp. 137-158

“Reproductive filtering and the social environment” SK Wasser and N. Place

2001 Western Black Bear Workshop, 7: 24-29

“Technical considerations for hair genotyping methods in black bears” CM Clarke, DA Immell, SK Wasser

2001 Ursus, 12: 237-240

“Fecal DNA methods for differentiating grizzly bears from black bears” CM Clarke, JA Fangman, SK Wasser

2001 Tabiatni muhofaza qilish biologiyasi, 15: 1134-1142

“Non-invasive stress and reproductive measures of social and ecological pressures in free-ranging African elephants (Loxodonta africana)” CAH Foley, S Papageorge, SK Wasser

2000 General and Comparative Endocrinology, 120: 260-275

“A generalized fecal glucocorticoid assay for use in a diverse array of non-domestic mammalian and avian species” SK Wasser, KE Hunt, JL Brown, K Cooper, CM Crockett, U Bechert, JJ Millspaugh, S Larson, SL Monfort

2000 Molecualr Ecology, 9: 993-1011

“Polymorphic microsatellite DNA loci identified in the African elephant (Loxodona africana)” KE Comstock, SK Wasser, EA Ostrander

2000 American Journal of Primatology, 51: 229-241

“Lifetime reproductive success, longevity, and reproductive life history of yellow baboons (Papio cynocephalus) of Mikumi National Park, Tanzania” RJ Rhine, G Norton, SK Wasser

1999 General and Comparative Endocrinology, 114: 269-278

“Serum prolactin concentrations in the captive female African elephant (Loxodonta africana): Potential effects of season and steroid hormone interactions” U.S. Bechert, L. Swanson, SK Wasser, D.L. Hess, F. Strormshak

1999 American Journal of Obstetrics and Gynecology, 180: S272-274

“Stress and Reproductive Failure: An Evolutionary Approach with Applications to Premature Labor” SK Wasser


RATIONALE

As explained before, the four SR populations have a strong female bias. If Fisher's Principle really works, it will select for the autosomal suppressors and gradually restore equal sex proportions. Only the autosomes are genetically variable so, barring mutation, sex chromosomes could not cause changes in the sexual proportion. The SR populations carry a X-Y meiotic drive system but this does not violate the Fisher's Principle assumption of Mendelian segregation of the alleles controlling the sexual proportion: the control was effectively autosomal, for the SR va Y chromosomes were fixed. The control was also parental (and not zygotic): the autosomal suppressors are expressed in the parental males.

Now suppose that we do observe an increase in the male proportion. A general and robust demonstration of Fisher's Principle would require testing three critical predictions: (i) there must be enough autosomal genetic variation in the sexual proportion to account for its observed rate of change (ii) this change should have been caused by the increase in the frequency of the autosomal alleles that direct the reproduction to the rare sex, the males (iii) female excess, rather than pleiotropic fitness effects, should have caused the spread of these alleles. These tests guard us against “mimic” evolutionary forces, such as sex chromosome effects and natural selection unrelated to Fisher's Principle. Prediction (i) was tested by estimating the realized heritability of the sexual proportion. If Fisher's Principle was the cause of the increase of male proportion, then a direct measurement of h 2 in the same populations (masalan, by father-offspring regression V arandas va boshqalar. 1997) should produce a compatible value.

The ST populations allowed the test of predictions (ii) and (iii): as these populations could not have suffered the Fisherian selection (because they lack the female excess), their autosomes were nearly equivalent to a “sample” of the autosomes from the SR populations at generation 0. By comparison between the autosomes from the ST va SR populations at the end of the experiment, we could verify whether SR populations accumulated autosomal suppressors (prediction ii). At the same time, possible pleiotropic fitness effects (of the autosomal suppressors) unrelated to Fisher's Principle were automatically discounted (prediction iii) because they should affect SR va ST populations equally. Thus, if these two Fisher's Principle predictions hold true for our experimental system, then the autosomes of the SR populations should have more suppressor alleles than the autosomes from the ST populyatsiyalar. This comparison was carried out as described before (Figure 1): the autosomes from the four SR and the two ST populations were introgressed into a reference SR strain the resulting SR/Y males were crossed and their progenies were counted.

Finally, mutation might have introduced Y variation and caused artifacts. This possibility was tested with populations 7 and 8 (see results ).

Evolution of the sexual proportion in the four SR populyatsiyalar. (A) Populations 1–4. The linear regression is shown. (B) Each point is the average of the four populations. The line is the best fit Fisherian trajectory (Equation 1 parameters: M0 = 0.164 Vp h 2 = 0.00466).


Videoni tomosha qiling: #20 Doktor D: JINSIY ALOQA QANCHA BOLISHI KERAK? (Avgust 2022).