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Qonuni tozagii gametaho

Dar natijai tajribaho G.Mendel ba khulosa omad, ki omilhoi irsi, yane genho dar gametaho (hujayrahoi jinsi) omekhta nashuda, dar holati toza (betagyir) memonand. Dar naslhoi yakumi gibridi (G1) ki az duragakunii volidon alo- mathoi farqkunanda paydo shudaand, hardu omil, yane dominanti va resessivi joy dorad. Dar shakli alomat omili dominanti zohir shuda, omili resessivi parokanda shudaast. Dar vaqti afzoishi jinsi robita dar bayni naslho ba vositai hujayrahoi jinsi va zigota (tukhmi bordor) meguzarad. Az taqsimshavii meyoz malum ast, ki dar gametaho az jufti omilho tanho yak omil (gen) joy dorad.

gametaDar vaqti bordori, yane omezishi du hujayrai jinsi (narina va modina), ki dar tarkibashon omilhoi irsii resessivi dorand, fardhoi alomathoyashon resessiviro paydo mekunand. Dar asnoi omezishi (yakjoyashavii) gametahoi doroi alomati dominanti, yo az du gameta yaktoash doroi geni dominanti va digarash geni resessivi, organizmhoi alomatashon dominanti ba vujud meoyand. Hamin tavr, zohirshavii alomati resessivii yake az volidon (R) dar nasli duvvum (G2) dar mavridi rioya kardani sharthoi zerin amali megardad:

  1. Dar mavride, ki alomathoi irsii gibrid betagyir nigoh doshta shavand.
  2. Modome, ki hujayrahoi jinsi (gametaho) doroi yake az jufti alleli genho boshand.

Tajziyai alomathoro dar naslhoi duragashudai fardhoi geterozigoti Mendel chunin sharh medihad: gametaho az jihati genetiki toza (pok)-and, yane dar gametaho az jufti allelii genho tanho yak gen joy dorad. Az in jo, qonuni to- zagii gametahoro chunin sharh dodan mumkin ast: dar rafti paydoishi hujayrahoi jinsi (gametaho) har yaki on faqat doroi yake az genhoi jufti alleli meboshad.

Sabab dar on ast, ki dar har hujayrai organizm miqdori muayyani khromosomahoi yakkhelai diploidi joy dorad. In khromosomahoi yakkhelaro khromosomahoi gomologi menomand va dar du khromosomai gomologi du alleli yakkhela (gen) joy-gir shudaand. Paydoishi gametahoi tozai genetikiro bo chunin skhema nishon dodan mumkin ast:

Badi omezishi gametai modina va narina, duragai nasli yakum (G1) bo miqdori khromosomahoi diploidi paydo meshavad:

Az naqsha barmeoyad, ki zigota nisfi khromosomahoro az modar va nisfi digarro az padar megirad. Dar rafti paydoishi gametaho dar duragaho khromosomahoi gomologi dar davri yakumi taqsimshavii meyozi dar hujayrahoi gunogun joygir meshavand:

Taqsimoti fenotipi va genotipi dar naslhoi duragai du organizmi geterozigoti chunin ast:

Dar naqsha asosi sitologii tajziyai monogibridii alomatho dar naslhoi duraga nishon doda shudaast. Asosi onro taqsimshavii khromosomahoi gomologi dar rafti meyoz muayyan karda, gametahoi gaploidi paydo meshavand, badi bordorshavi boz khromosomahoi gomologii diploidi ba vujud meoyand. Hamin tariq, az in jufti alleli du nav gameta paydo meshavad. Dar jarayoni bordori gametahoi yakkhela yo gunogun tasodufan ba ham omekhta meshavand. Muvofiqi nazariyai ehtimoliyati matematiki, agar miqdori fardho nisbatan ziyod boshand, dar naslho 25%-genotipho gomozigotii dominanti, 50%-geterozigoti, 25%- gomozigotii resessivi paydo meshavand. YAne 1AA: 2Aa:1aa. Dar naslhoi duyumi duragahoi monogibridi boshad, tanosubi taqsimoti shaklhoi fenotipi chunin ast: 3/4 hissai fardho bo alomati dominanti va 1/4 hissai onho bo alomati resessivi (3:1).

 

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