Ama-chromosomes wamadoda. I-y-chromosome yiphi imithonya nokuthi yiziphi izimpendulo?

Isihloko socwaningo lwezakhi zofuzo yisimangaliso sokuzalwa nokuhlukahluka. Usosayensi waseMelika T-X. UMorgan wadala i-chromosome theory of heredity, efakazela ukuthi izinhlobo zonke zingabonakaliswa ngekaryotype ethile equkethe izinhlobo ezinjalo zama-chromosomes njenge-somatic nezocansi. Lezi zinsuku zimelelwa yiqembu elihlukile, elihlukile kubantu abesilisa nabesifazane. Kulesi sihloko, sizofunda ukuthi iziphi ama-chromosomes ezinsikazi nabesilisa abanayo nokuthi zihluke kanjani phakathi kwazo.

Iyini i-karyotype?

Iseli ngalinye eliqukethe i-nucleus libhekene nenani elithile lama-chromosomes. Ithole igama elithi karyotype. Ezinhlobonhlobo ezihlukahlukene zezinto eziphilayo, ukutholakala kwezingxenye zomzimba eziphathelene nokuzalwa kuyisibonelo esithile, isibonelo, i-karyotype yomuntu ingama-chromosomes angu-46, ema-chimpanzees - 48, nasemifuleni ye-crayfish - 112. Isakhiwo sabo, ubukhulu, ukuma kwazo kuhluke kubantu abahlukene be-taxa ehlelekile. Inani lama-chromosomes esitokisini somzimba libizwa ngokuthi isethi ye-diploid. Kuyisici sezitho zangasese nezicubu. Uma i-karyotype ishintshe ngenxa yenguquko (isibonelo, kuziguli ezine-syndrome ka-Klinefelter inani lama-chromosomes liyi-47, 48), ngakho-ke abantu abanjalo baye banciphisa ukuzala futhi ezimweni eziningi abanamandla. Esinye isifo esiyingqayizivele esithinta ama-chromosomes ngokocansi yi-Turner-Shereshevsky syndrome. Kwenzeka kwabesifazane abanama-karyotype hhayi 46 kodwa ama-chromosomes angu-45. Lokhu kusho ukuthi emkhatsini wezocansi azikho ama-x-chromosomes amabili, kodwa kuphela. Ngokucabangela, lokhu kubonakala ekuthuthukiseni kwezingcansi zobulili, kubonakala sengathi abalingiswa bobulili bobubili kanye nabangasebenzi.

Ama-chromosomes angamaSomatic kanye nocansi

Zihlukile kokubili ifomu kanye neqoqo lezakhi zofuzo ezakha ukwakheka kwazo. Ama-chromosomes amantombazane abantu kanye nezilwane ezincelisayo zifaka umbhangqwana wobulili we-heterogametic XY, ohlinzeka ngentuthuko kokubili izici zesondo zobulili ezisemqoka neziyisithupha. Ezinyoni zezinsikazi, umbhangqwana wezocansi uqukethe ama-chromosomes amabili efana neZZ futhi ubizwa ngokuthi i-homogametic. Ngokungafani nama-chromosomes, okunquma ubulili bomzimba, kunezinhlaka ze-karyotype ezifanayo kubesilisa nabesilisa. Zibizwa ngokuthi ama-autosomes. Karyotype yomuntu, kunezibili ezingu-22. Ama-chromosomes abesilisa nabesifazane afaka ama-pair amabili, ngakho-ke i-karyotype yesilisa ingamelwa njengefomula jikelele: ama-pair amabili we-autosomes + XY, nabesifazane - ama-pair amabili we-autosomes + XX.

I-Meiosis

Ukwakhiwa kwe-gametes, i-gametes, ne-fusion ye-zygote eyakhiwa ngayo, kwenzeka emaqenjini omzimba: ama-testes nama-ovaries. Ezingxenyeni zabo, i-meiosis ivela - inqubo yesigaba se-cell esenza ekwakheni i-gametes equkethe isethi yamaglodi yama-chromosomes. I-Ovogenesis ema-ovarie iholela ekuvuthweni kwamaqanda ngezinhlobo ezilodwa kuphela: i-autosomes + X, ne-spermatogenesis iqinisekisa ukuvuthwa kwama-homometes ezinhlobo ezimbili: 22 ama-autosomes + X noma ama-autosomes angu-22 + U. Kubantu, ubulili bomntwana ongakazalwa bunqunywe ngesikhathi sokuhlanganiswa kwe-nuclei yeqanda nesidoda Kusukela ku-karyotype yesidoda.

Indlela ye-Chromosome nokuzimisela ngokocansi

Sesivele sibheke ukuthi yikuphi ukucatshangelwa kobulili kubantu - ngesikhathi sokukhulelwa, futhi kuxhomeke kwisethi ye-chromosome yesidoda. Kwezinye izilwane, abameleli bobulili obuhlukile bahluke ngamanani ama-chromosomes. Isibonelo, ezinambuzweni zasolwandle, izinambuzane, izintethe esitokisini sezindiza ze-diploid kukhona i-chromosome eyodwa kuphela kusuka ebesini sobulili, nakwesifazane - kokubili. Ngakho-ke, iqoqo le-haploid lama-chromosomes wamantombazane ama-acanthocanthus emanzini angaboniswa ngamafomula: ama-chromosomes + ama-5 noma ama-5 ama-chromosomes + x, nabesifazane baneqoqo elilodwa kuphela lama-chromosomes + x ema-ovules.

Yini ethonya isifo socansi?

Ngaphandle kwe-chromosomal, kunezinye izindlela zokunquma ubulili. Kwamanye ama-invertebrates - ama-rotifers, ama-polychaete ama-worms - ubulili bunqunywa ngisho nangaphambi kokuhlanganiswa kwe-gamete ukukhulelwa, ngenxa yalokho ama-chromosomes abesilisa nabesifazane enza ama-homologous pair. I-sea sea polychaetes - i-dinofilus enqubo ye-ovogenesis yakha i-ovule yezinhlobo ezimbili. I-yolk yokuqala, encane, ehluphekayo, - iyakhula abesilisa. Ezinye - ezinkulu, ezinomsoco omkhulu - zisebenzela ukuthuthukisa abesifazane. Kuzinyosi zezinyosi - izinambuzane zochungechunge lwe-Hymenoptera - abesifazane baveza izinhlobo ezimbili zamaqanda: i-diploid ne-haploid. Amaqanda angenalutho, abesilisa bakhula - ama-drones, futhi kusukela kumaqanda okukhulelwa - abesifazane abasebenzisa izinyosi.

Amahomoni kanye nemiphumela yabo ekubunjweni kobulili

Emadodeni, izigulane zesilisa - ama-testicles - akhiqiza ama-hormone ocansini we-testosterone amaningi. Zithinta kokubili ukuthuthukiswa kwezici zobulili eziyinhloko (isakhiwo samathambo sezitho zangasese zangaphandle nezangaphakathi) kanye nezici ze-physiology. Ngaphansi kwethonya le-testosterone, izici zesondo zobulili eziyisisekelo zakhiwe - isakhiwo samasaka, izici zesibalo, izinwele zomzimba, isithwathwa sezwi, nesakhiwo se-larynx. Emzimbeni wesifazane, ama-ovaries akhiqizi kuphela amangqamuzana ezocansi, kodwa futhi amahomoni, okuyizigcawu eziyimfihlo yokufihla. Ama-hormone e-sex efana ne-estradiol, i-progesterone, i-estrogen, akhuthaza ukuthuthukiswa kwezitho zangasese zangaphakathi nezangaphakathi, izinwele zomzimba ngohlobo lwesifazane, ukulawula umjikelezo wesimiso kanye nenkambo yokukhulelwa. Kwezinye izilwanyana eziphilayo, izinhlanzi, izinambuzane kanye nama-amphibians, izinto eziphilayo ezisebenzayo ezikhiqizwa yi-gonads zithonya kakhulu ukuthuthukiswa kwezici zobulili eziyinhloko nezesekondari, futhi izinhlobo ze-chromosome azikho ithonya elikhulu ekubunjweni kobulili. Isibonelo, izibungu zamapayipi amathemikhumbi olwandle - i-bonellia - ngaphansi kwethonya lama-hormone wesifazane ocansini alinqanda ukukhula (1-3 mm ngobukhulu) futhi abe ngamadoda abesilisa abancane. Bahlala emkhakheni wezinsikazi wezinsikazi, ezinomzimba womzimba ongaphezu kwamamitha ayi-1. Ezinhlanzi-abahlanza izinhlanzi ziqukethe ama-harems kusuka kwabesifazane abaningana. Abantu besifazane, ngaphandle kwama-ovari, babe nesitshalo se-embryonic. Ngokushesha nje lapho owesilisa efa, enye yezinsikazi ezithatha isenzo sayo (emzimbeni wayo, ama-gonads abesilisa abathuthukisa ama-hormone ezocansi aqala ukuthuthukisa).

Ukulawulwa phansi

Ezenzweni zofuzo zomuntu, lenziwa yimithetho emibili: owokuqala unquma ukuxhomekeka kokuthuthukiswa kwezinhlayiya zobulili ezingcolile ekusithekeni kwe-testosterone ne-hormone MIS. Umthetho wesibili ubonisa indima ehlukile edlalwa yi-Y chromosome. Ubulili besilisa kanye nazo zonke izibonakaliso ezihambisana nesimo nesimo sezinto ezakhiwa ngaphansi kwethonya lamagciwane ase-Y chromosome. Ubuhlobo nokuxhomeka kokubili kwemithetho ebizwa ngokuthi i-genetic yomuntu kuthiwa yisimiso sokukhula: embuthwaneni onesisini (okungukuthi, imigodi yezinsikazi - umzila wama-Mullerian ne-gonad yesilisa - i-Wolff canal), ukuhlukaniswa kwe-gryad gland gland kuxhomeke ekubeni khona noma ukungabikho kwe-chromosome Y e-karyotype.

Ulwazi lwezofuzo ku-Y chromosome

Ucwaningo lwesayensi yezofuzo, ikakhulukazi i-T-X. UMorgan, itholakala ukuthi ukubunjwa kwezakhi ze-X- ne-Y-chromosomes akufani kubantu nasezilwaneni ezincelisayo. Ama-chromosomes wamadoda kubantu abanayo ama-alleles akhona ku-X chromosome. Kodwa-ke, i-gene pool yabo iqukethe igciwane le-SRY, elilawula i-spermatogenesis, eholela ekusungulweni kobulili besilisa. Ukuphazamiseka kwe-hereditary yalesi sifo ku-embryo kuholela ekuthuthukiseni isifo sofuzo - i-Suair syndrome. Ngenxa yalokho, owesifazane ovela kulowo mbungu uqukethe umbhangqwana wobulili ku-karyotype ye-XY noma ingxenye kuphela ye-chromosome Y ene-locus yegeni. Uvuselela ukuthuthukiswa kwe-gonads. Ezigulini, abesifazane abahlukanisi izici zesondo zobulili zesibili, futhi bangabumba.

Izifo ze-U-chromosome nezifo

Njengoba kuphawuliwe ngaphambili, i-chromosome yesilisa ihluke kwi-X ye-chromosome kokubili ngobukhulu (incane) futhi ifomeni (ibonakala njenge-hook). Futhi ngesethi yayo ethize yezinhlobo zomzimba. Ngakho-ke, ukuguqulwa kwesinye sezakhi zofuzo ze-Y chromosome kubonakala ngobuciko ngokubonakala kwesigxobo sezinwele ezinzima e-earlobe. Lesi sici isici kuphela samadoda. Isifo esizalwa yizifo ezibangelwa ukuguquguquka kwe-chromosomal saziwa ngokuthi yi-Klinefelter's syndrome. Indoda egulayo inama-karyotypes abesifazane abangenangqondo noma ama-chromosomes omuntu: ХХУ or ХХУУ. Izibonakaliso eziyinhloko zokuxilonga ukukhula kwamathambo ezincane ze-mammary, i-osteoporosis, ukungabi namandla. Lesi sifo sivame kakhulu: kuwo wonke ama-500 azalwa asanaba nesineke esisodwa.

Ukufingqa, siyabona ukuthi kubantu, njengabanye abilisiwe, ubulili bezilwane ezizayo buyonqunywa ngesikhathi sokukhulelwa, ngenxa yenhlanganisela ethile kwi-zygote ye-X-ne-Y-chromosomes.