Male DNA. Pa Y-khromozomu imagwira ndi udindo wotani?

Phunziro la kafukufuku majini - zachilengedwe cha chibadwa ndi kusintha. American Scientist T-X. Morgan analenga khromozomu chiphunzitso cha chibadwa, nawatsimikizira kuti aliyense zamoyo zikhoza zimaonetsa karyotypes ena kuti muli mitundu ya DNA monga somatic ndi nyongolosi. Recent ankaimira awiri osiyana amasiyana amuna ndi akazi. M'nkhaniyi, tiona mmene kapangidwe ali DNA mwamuna ndi mkazi momwe iwo amasiyana pakati pawo.

Kodi karyotype?

Uliwonse uli selo pachimake amakhala ndi muyezo winawake DNA. Iwo akutchedwa karyotype. Mu mitundu yosiyanasiyana pamaso mayunitsi structural cha chibadwa ali mosamalitsa yeniyeni, mwachitsanzo, karyotype anthu DNA 46 anyani - 48 nsomba zazinkhanira - 112. dongosolo lawo, kukula, kuumba osiyana kwa anthu linali la taxa osiyana taxonomic. topangira DNA mu khungu la thupi amatchedwa diploid. Ndi mmene kwa ziwalo somatic ndipo zimakhala. Ngati chifukwa cha masinthidwe karyotype kusintha (mwachitsanzo, odwala ndi Klinefelter Syndrome chiwerengero DNA 47, 48), anthu amenewa achepetsa chonde milandu ndipo ambiri zaonongeka. cholowa matenda ena amagwirizana ndi DNA kugonana - Turner syndrome-Shereshevscky. Kumachitika mu akazi amene alibe mu karyotype 46, 45 DNA. Izi zikutanthauza kuti banja kugonana palibe awiri X DNA, koma mmodzi yekha. Phenotypically akuwonetseredwa mu underdevelopment wa gonads ndi bwino kumatanthauza sekondale makhalidwe kugonana ndi osabereka.

Somatic ndi kugonana DNA

Akusiyana onse mu mawonekedwe, komanso chibadwa mwa iwo. Anthu wamwamuna DNA ndi zolengedwa zoyamwitsa m'gulu la heterogametic awiri kugonana XY, kupereka chitukuko onse khalidwe lachimuna kugonana pulayimale ndi sekondale. Amuna, awiri kugonana mbalame limapangidwa awiri DNA zofanana ZZ mwamuna wotchedwa homogametic. Mosiyana DNA kuti kudziwa kugonana a chamoyo, kumtundu dongosolo karyotype zofanana onse aamuna ndi aakazi. Iwo akutchedwa autosomes. Mu karyotype anthu a awiriawiri 22. Mwamuna ndi mkazi DNA kugonana kupanga 23 awiri ndi, kotero karyotype wa munthu akhoza ankayimiridwa ngati chilinganizo ambiri: awiriawiri 22 autosomes + XY, ndi akazi - awiriawiri 22 autosomes + XX.

meiosis

Mapangidwe maselo nyongolosi - gametes, amene anapanga pa confluence a zygote kumachitika mu gonads: testes ndi thumba losunga mazira. zimakhala anachita meiosis - ndondomeko ya kugawikana khungu, chifukwa mu mapangidwe gametes munali haploid ya DNA. Oogenesis yamchiberekero oocyte kusasitsa kumayambitsa mitundu chimodzi chokha: X + 22 autosomes ndi kusasitsa wa spermatogenesis gomet amapereka mitundu iwiri ya 22 autosomes ndi X + 22 autosomes + Y. Mwa anthu kugonana mwana anatsimikiza pa nthawi ya Zisudzo za umuna ndi dzira mtima ndipo zimadalira kuchokera karyotype umuna.

Khromozomu ndi limagwirira a mtima kugonana

Takambirana kale kufika pa zomwe pali kugonana kutsimikiza anthu - panthawi ya umuna, ndipo zimadalira DNA a dontho la umuna. Mu nyama zina za amuna ndi akazi amasiyana topangira DNA. Mwachitsanzo, nyongolotsi m'madzi, tizilombo ziwala amuna diploid, pali khromozomu umodzi wokha wa peyala ya kugonana, pamene akazi - onse. Choncho, msilikaliyo nyongolotsi haploid ya DNA wamwamuna atsirokantusa tingasonyezere mwa mitunduyi ndi: 0 + 5 DNA kapena khromozomu 5 + ×, ndi akazi ndi mazira, imodzi yokha ya DNA 5 + x.

amakhudza Kodi dimorphism kugonana?

Kuwonjezera chromosomal pali njira zina kudziŵa kugonana. Ena invertebrates - rotifers, polychaetes - kugonana anatsimikiza pamaso pophatikizana a gametes - umuna, imene mwamuna ndi DNA wamkazi kupanga nsapato magazi. Akazi m'madzi polychaete - dinofilyusa pa oogenesis kupanga mitundu iwiri ya dzira. The choyamba - ang'ono losauka yolk - ndi amuna kukhala. Ena - lalikulu, ndi chakudya yaikulu zakudya - ntchito chitukuko cha akazi. Mu uchi njuchi - chiwerengero cha tizilombo Hymenoptera - akazi mitundu iwiri ya mazira: diploid ndi haploid. Mazira unfertilized amatswa amuna - ndi drones ndi umuna - akazi ndi ntchito njuchi.

Mahomoni ndi zotsatira zawo pa mapangidwe jenda

Anthu, mwamuna zopangitsa - testes - kubala kugonana mahomoni testosterone zino. Zikukhudzira onse chitukuko cha makhalidwe kugonana chachikulu (loukitsa anatomical ziwalo mkati ndi kunja maliseche), ndi Maphunziro Akakhalidwe Kazolengedwa makamaka. Mothandizidwa testosterone anapanga sekondale makhalidwe kugonana - dongosolo la mafupa, makamaka Chiwerengerochi, tsitsi thupi thupi, mawu, kapangidwe ka m'mphako ya. thupi la mkaziyo mazira kubala osati maselo ubereki, komanso mahomoni, monga secretions England osokonezeka. Kugonana mahomoni monga estradiol, progesterone, esitirojeni, amathandiza kuti chitukuko cha kumaliseche kunja ndi mkati, thupi tsitsi kufalitsa mtundu wamkazi, zonse otaya msambo ndi mimba. Ena inakhala, nsomba, annelids ndipo achule biologically yogwira opangidwa ndi gonads ndi, amatsogolera chitukuko cha makhalidwe pulayimale ndi sekondale kugonana, ndi mitundu DNA Pankhaniyi mulibe zimakhudza kwambiri pa mapangidwe jenda. Mwachitsanzo, mphutsi za polychaete m'madzi - Bonelli - mchikakamizo mahomoni wamkazi Kusiya kukula (kukula 1-3 mm) ndi nyenyezi yaing'ono amuna. Iwo amakhala mu kapepala maliseche a akazi amene ali ndi thupi kutalika kwa 1 mita. Mu nsomba okonza muli harems wamwamuna wa akazi angapo. Akazi, kupatula mazira, ndi zoyambira za testes lapansi. Mwamsanga pamene mwamuna wamwalira, mmodzi wa gulu la akazi a akazi zimatengera pa ntchito yake (mu thupi lake anayamba mwachangu kukhala gonads wamwamuna yotulutsa timadzi kugonana).

lamulo kugonana

Mu chibadwa anthu, izo ikuchitika malamulo awiri: loyamba limatanthauzira ubale wa gonads achikalekale ku katulutsidwe wa testosterone ndi Mis timadzi. Lamulo lachiwiri limasonyeza kwambiri ntchito za Y-khromozomu. Male kugonana ndi zizindikiro zake zonse lolingana anatomical ndi thupi kukhala mchikakamizo cha chibadwa ili mu Y-khromozomu. Interrelationship ndi kudalira malamulo onse a chibadwa anthu imatchedwa Mfundo kukula: mwa mwana wosabadwayo, ndilo bisexual (ili zoyamba za zopangitsa wamkazi - Mullerian ritsa ndi gonads wamwamuna - Wolffian ritsa) zosiyanasiyana za gonad embryonic zimadalira pamaso kapena kusapezeka mu karyotype Y khromozomu.

uthengawu ku maselo a Y-khromozomu

Studies geneticists, makamaka T-X. Morgan, chinapezeka kuti anthu ndi nyama, kapangidwe jini ya X ndi Y DNA sali yemweyo. Male DNA anthu ena alleles analipo pa X khromozomu. Komabe, mu dziwe awo jini ankaimira SRY jini kulamulira spermatogenesis, zikubweretsa mapangidwe chiwalo chachimuna. matenda cholowa cha jini izi Ndisanaumbidwe amatsogolera kuti chitukuko cha matenda majini - Suayra syndrome. Chifukwa cha zimenezi, akazi osauka chifukwa cha mwana wosabadwayo lili XY karyotype awiri kugonana kapena ndi gawo la Y-khromozomu munali locus mbewu. Iwo imayendetsa chitukuko cha gonads lapansi. Odwala akazi kusiyanitsidwa sekondale makhalidwe kugonana, ndipo iwo n'ngosabereka.

Y-khromozomu ndi matenda majini

Monga taonera kale, kuti asakhale ndi vutoli mwamuna wosiyana X-khromozomu monga kukula (ndi zing'onozing'ono) ndi mawonekedwe (a mtundu mbedza). Komanso iye, ndipo amaika yeniyeni imene imachititsa. Mwachitsanzo, kusintha kwa mmodzi wa chibadwa mu khromozomu ndi phenotypically owonetseredwa maonekedwe a coarse tsitsi mtolo pa khutu la. Mbali imeneyi ndi khalidwe chabe kwa anthu. Amadziwika matenda otengera chifukwa cha chromosomal kusintha ngati syndrome Klinefelter. Munthu wodwala ali karyotype owonjezera wamkazi kapena wamwamuna DNA: XXY kapena HHUU. Waukulu matenda Mbali kukula pathological wa zopangitsa mammary, kufooka kwa mafupa, osabereka. matenda ndi zachilendo: iliyonse anyamata 500 akhanda 1 mtima.

Kuti adzimvera, tiona kuti anthu a ku nyama zina, kugonana kwa chamoyo anatsimikiza panthawi ya umuna, chifukwa osakaniza winawake wa zygote X ndi Y kugonana DNA.