Li cas ywj siab assortment nce genetic ntau haiv neeg?
Li cas ywj siab assortment nce genetic ntau haiv neeg?

Video: Li cas ywj siab assortment nce genetic ntau haiv neeg?

Video: Li cas ywj siab assortment nce genetic ntau haiv neeg?
Video: koj nyob li cas lawm qub swm nkauj 2024, Kaum ib hlis
Anonim

Genetic ntau haiv neeg yog nce los ntawm ywj siab assortment ( noob tau txais kev ywj pheej ntawm ib leeg) thiab hla thaum meiosis. Thaum lub sij hawm meiosis, chromosomes (uas pom nyob rau hauv khub) sib pauv loj feem ntawm lawv cov molecules, ua rau caj ces cov khoom yuav tsum sib xyaw ntawm lawv.

Nyob rau hauv no hais txog, ua li cas ywj siab assortment muaj feem xyuam rau genetic ntau haiv neeg?

Meiosis thiab Genetic Variation . Thaum cov hlwb sib faib thaum lub sij hawm meiosis, homologous chromosomes raug faib randomly faib thaum lub sij hawm anaphase I, sib cais thiab cais. ywj siab ntawm ib leeg. Qhov no hu ua ywj siab assortment . Nws ua rau gametes uas muaj qhov sib xyaw ua ke ntawm chromosomes.

Qhov thib ob, yuav ua li cas random fertilization ntxiv rau genetic variation? Cov random xwm ntawm fertilization ntxiv rau noob caj noob ces variation tshwm sim los ntawm meiosis. Txhua tus phev tuaj yeem fuse nrog txhua lub qe. Ib tug zygote tsim los ntawm mating ntawm ib tug poj niam thiab txiv neej muaj ib tug tshwj xeeb caj ces tus kheej. Hla mus ntxiv ntau dua kev hloov pauv rau qhov no.

Xav txog qhov no, yuav ua li cas hla kev nce kev sib txawv ntawm caj ces?

Hla mus , los yog recombination, yog kev sib pauv ntawm chromosome ntu ntawm nonsister chromatids hauv meiosis. Hla mus tsim tshiab ua ke ntawm noob nyob rau hauv gametes uas tsis pom nyob rau hauv ob niam txiv, contributing rau muaj ntau haiv neeg.

Dab tsi yog qhov tshwm sim ntawm kev hla dhau thiab kev ywj pheej assortment hauv meiosis?

Hla - dhau yog kev sib pauv ntawm cov khoom siv caj ces ntawm homologous chromosomes. Nws tshwm sim hauv kev sib txuas tshiab ntawm cov noob ntawm txhua tus chromosome. Thaum cov hlwb sib faib thaum lub sijhawm meiosis , homologous chromosomes random faib rau cov ntxhais cell, thiab sib txawv chromosomes cais. ywj siab ntawm ib leeg.

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