Zofuzo Male. Kwi-Y-chromosome oluchaphazela kwaye linoxanduva ntoni?

Isifundo kuphando lwemfuzo - le nesenzeko kwimfuza kunye nomahluko. American Scientist T-X. Morgan wadala imfundiso chromosome kwimfuza, ebonakalalisa ukuba iintlobo ngalinye iimpawu karyotypes ezithile equlathe ezi ntlobo zofuzo njengoko somatic kunye lwegciwane. Lwakutsha nje amelwe izihlangu eyahlukileyo bahluka amadoda kunye nabasetyhini. Kweli nqaku, siza kuhlolisisa indlela Isakhiwo zofuzo bayindoda nenkazana nokuba zahluke njani phakathi kwabo.

Yintoni karyotype?

Nganye core equlethe Iseli iphawulwa isixa esithile zofuzo. Ibizwa ngokuba karyotype. Xa iintlobo ezahlukileyo phambi kweeyunithi noshowo ufuzo ngokungqongqo ezithile, umzekelo, karyotype abantu 46 zofuzo bangafani - 48 yenamvuna - 112. Ukwakhiwa kwazo, ubungakanani, balolonge ezahlukeneyo ukusuka abantu abangabakhe zohlaza ezahlukeneyo taxonomic. Inani zofuzo esiseleni umzimba kuthiwa diploid. Kuyinto eqhelekileyo ukuba amalungu somatic kunye namalaphu. Ukuba ngenxa yemfuza karyotype utshintsho (umz, xa izigulane Klinefelter Syndrome inani zofuzo 47, 48), aba bantu ziye zancitshiswa wenzala kwiimeko ezininzi ayiphumelelanga. Okunye isifo ilifa ezinxulumene zofuzo sex - Turner syndrome-Shereshevscky. Senzeka abafazi aninalo ngaphakathi kule karyotype 46, kunye 45 zofuzo. Oku kuthetha ukuba esi sibini ngokwesini akakho zofuzo ezimbini X, kodwa mnye kuphela. Phenotypically wabonakaliswa lokungaphuhliswa gonads, kakubi defined iimpawu eziziisekondari ngokwesondo kunye ukungachumi.

Somatic kunye sex zofuzo

Ahluke kokubini ifomu kunye iseti yemfuza ngaphakathi kubo. zofuzo oyindoda Human kunye mammalian ifakiwe kwisibini ngesondo heterogametic XY, ukubonelela zophuhliso iimpawu oyindoda sex eziziprayimari nezizisekondari. Xa eyindoda, ngokwesondo iintaka isibini yenziwa zofuzo ezimbini twatse ZZ eyindoda ebizwa homogametic. Ngokungafaniyo zofuzo ezibonakalisa besini le ephilayo, ilifa isakhiwo karyotype zifana ncam zombini iinkunzi kunye nemazi. Ewe kuthiwa autosomes. Xa karyotype abantu izibini 22. zofuzo sex indoda nenkazana zenza 23 ipere, ngoko ke karyotype womntu angamelwa njengoko ifomula ngokubanzi: 22 izibini autosomes + XY, nabafazi - 22 izibini autosomes + XX.

meiosis

Formation kweeseli lwegciwane - gametes, oluthi luqokelelane kwi ekudibaneni elilodwa lwenzeka kwi gonads: namasende kunye zamaqanda. Ezi kwinyama wenza meiosis - inkqubo kwisahlulo iseli, kukhokelele kwinto yokuba kusekwe gametes eziqulathe iseti haploid zofuzo. Oogenesis kweqanda ovarian ekukhuleni kwengqondo kukhokelela uhlobo olunye kuphela: X + 22 autosomes kunye ekukhuleni spermatogenesis gomet ubonelela iintlobo ezimbini autosomes 22 kwaye X + 22 autosomes + uY In abantu lwesini sana umiselwa ngexesha ngxubevange isidoda neqanda nuclei ithembele ukusuka karyotype isidoda.

Chromosome kunye indlela nokuzimisela sex

Sele ingqalelo indawo apho kukho ukuzimisela sex ebantwini - ngalo mzuzu neqanda, kwaye kuxhomekeke kwi zofuzo lwe yobudoda. Ngamanye izilwanyana ngokwesini zahluke inani zofuzo. Umzekelo, iintshulube zaselwandle, izinambuzane, iintethe kumadoda diploid, kukho enye kuphela chromosome lwe iperi ngesondo, ngexa amabhinqa - zombini. Ngoko ke, lo umbungu iseti elwandle haploid zofuzo atsirokantusa inkunzi kulubonakalisa yi iifomyula: 0 + 5 zofuzo okanye chromosome 5 + x, yaye amabhinqa akamelwanga e amaqanda, omnye kuphela iseti zofuzo 5 + x.

Yintoni ichaphazela dimorphism ngokwesini?

Ukongezelela chromosomal zikhona ezinye iindlela yokufumanisa i sex. Ezinye ezingenamqolo - rotifers, polychaetes - sex umiselwa phambi ngokudibana gametes - neqanda, apho inkunzi zofuzo nemazi zenza pair homologous. Abasetyhini polychaete zaselwandle - dinofilyusa ngexesha oogenesis ukwenza iintlobo ezimbini egg. Lokuqala - i, sac elincinane Sivikivekile - yeha ukuphuhlisa. Abanye - elikhulu, ezinawo elikhulu kwezondlo - asetyenziswa kuphuhliso nabasetyhini. Xa iinyosi ubusi - iqela izinambuzane Hymenoptera - iimazi ukuvelisa iintlobo ezimbini zamaqanda: diploid kunye haploid. Ukususela amaqanda unfertilized zikhule zibe eyindoda - i drones kunye aqhamileyo - amabhinqa akamelwanga iinyosi umsebenzi.

Hormone nefuthe lazo ukuyilwa yesini

Xa abantu, amadlala eyindoda - namasende - ukuveza sex hormone testosterone series. Ukuba nempembelelo nophuhliso iimpawu sex ephambili (isakhiwo yokwakheka amalungu obuni lwangaphakathi nolwangaphandle), kwaye zomzimba ethile. Phantsi impembelelo testosterone akhiwa iimpawu zamabanga ngesondo - isakhiwo amathambo, ingakumbi manani, iinwele umzimba umzimba, ilizwi, isakhiwo kwingqula. amaqanda umzimba waloo mfazi avelisa kuphela okuzala, kodwa hormone, njengoko netuwa ndlala kuxutywe. Sex iihomoni ezifana estradiol, dlala, estrogen, igalelo kuphuhliso eveze zangaphandle nezangaphakathi, umzimba ukusasazwa iinwele lohlobo ababhinqileyo, ukulawula nokuqukuqela sexesheni kunye nokukhulelwa. Ezinye ekuyo, intlanzi, annelids kunye eziphila eziphilayo izinto esebenzayo yenziweyo gonads, nempembelelo enkulu kuphuhliso neempawu zesini eziziiprayimari neziziisekondari, kunye neentlobo zofuzo kulo mzekelo musani kuba nempembelelo kangaka ukuyilwa kwisini. Umzekelo, ukuba ezidla polychaete zaselwandle - Bonelli - phantsi kweempembelelo iihomoni ababhinqileyo yekani kukhule (ubukhulu 1-3 mm) yeha ezincinanana. Zihlala kwisiqwenga obuni ababhinqileyo abaye abe ubude umzimba ukuya kutsho kwimitha 1. In iintlanzi-abacoci ziqulathe iimazi eyindoda nabasetyhini eziliqela. Abasetyhini, ngaphandle zamaqanda, zinto zikukuqaleka amatyhalarha. Kamsinya nje inkunzi esifa, omnye dlo iimazi kuthatha ngaphezu umsebenzi wayo (emzimbeni wayo ziqala ukukhula ngokubonakalayo gonads iinkunzi avelisa iihomoni ukulala).

ulawulo sex

E yemfuza yabantu, kuliwa yimithetho ezimbini: eyokuqala lichaza ukuzalana gonads sekukubi ukusuka secretion of testosterone kunye MIS hormone. Umthetho yesibini ibonisa indima ebalulekileyo edlalwa yi-Y-chromosome. elobuduna zonke iimpawu yayo ehambisana yokwakheka kunye nokomzimba zikhula phantsi kweempembelelo genes ebekwe kwi-Y-chromosome. Ukwalamana kunye nokuxhomekeka bobabini imigaqo yemfuza zabantu kuthiwa umgaqo lokukhula: kwi ndiseyimbumba, leyo ulala (it has zakuqala unamadlala ababhinqileyo - Mullerian bile kunye gonads eyindoda - duct Wolffian) umahluko le gonad osandul kuxhomekeke kubukho okanye zokungabikho emsebenzini karyotype Y chromosome.

imizila yemfuza Y-chromosome

Studies zofuzo, ingakumbi T-X. Morgan, kwafunyaniswa ukuba abantu nezilwanyana ezanyisayo, isakhiwo sofuzo we-X kunye Y zofuzo akufani. zofuzo eyindoda abantu kwezinye alleles ezikhoyo kwi-X chromosome. Nangona kunjalo, xa pool lwabo gene wamela SRY gene ukulawula spermatogenesis, ekhokelela ukuyilwa besini eyindoda. izifo ilifa yale sofuzo umbungu kukhokelela kuphuhliso sisifo yemfuza - Suayra syndrome. Ngenxa yoko, imazi asakhulayo ukusuka ndiseyimbumba enjalo iqulethe XY karyotype isibini ngokwesondo okanye inxalenye kuphela ye Y-chromosome equlathe babeziindawo sofuzo. Oyenza isebenze uphuhliso gonads. Izigulane abasetyhini abavumelekanga neenkalo neempawu zesini zasesekondari, kwaye azifumani.

Y-chromosome nezifo genetic

Njengokuba bekutshiwo ngaphambili, i-chromosome inkunzi ezahlukeneyo ukusuka X-chromosome nobungakanani (ukuba incinane) kunye nefomu (uhlobo hook). Kwakhona ngenxa yakhe, kunye iseti athile yemfuza. Umzekelo, kuguquka kwelinye zofuzo kwi chromosome kukho ukubonakala phenotypically wabonisa wenu kweenwele inyanda yendlebe. Lo msebenzi osemqoka iimpawu kuphela abantu. Yinto eyaziwa sisifo amafa esibangelwa kuguquka chromosomal efana Klinefelter syndrome. Le ndoda egulayo kwi karyotype nemazi engakumbi okanye zofuzo oyindoda: XXY okanye HHUU. Eyona iphambili diagnostic ke ukukhula zophendlo lwezifo kwamadlala mammary, kwamathambo, ukungachumi. Esi sifo yinto exhaphakileyo: kuzo zonke amakhwenkwe asandul 500 1 nomonde.

Ukushwankathela, siphawula ukuba abantu kwezinye izilwanyana ezanyisayo, besini yento ephilayo ixhomekeke ngalo mzuzu ifakwe, ngenxa kwindibaniselwano elithile a elilodwa X kunye zofuzo sex Y.