Nondisjunction tuaj yeem tshwm sim thaum anaphase of mitosis, meiosis I, lossis meiosis II. Thaum lub sij hawm anaphase, tus muam chromatids (los yog homologous chromosomes rau meiosis I), yuav sib cais thiab txav mus rau cov ncej ntawm tes, rub los ntawm microtubules.
Kev tsis sib haum xeeb yog dab tsi thiab nws tshwm sim thaum twg?
1 NONDISJUNCTION
Nondisjunction txhais tau hais tias ib khub ntawm homologous chromosomes tsis tau cais lossis cais ntawm anaphase kom ob leeg chromosomes ntawm khub dhau mus rau tib tus ntxhais cellQhov no feem ntau tshwm sim hauv meiosis, tab sis nws yuav tshwm sim hauv mitosis los tsim ib tus neeg mosaic.
Dab tsi ua rau chromosome nondisjunction?
Nondisjunction tshwm sim thaum homologous chromosomes (meiosis I) los yog tus muam chromatids (meiosis II) tsis cais thaum lub sij hawm meiosis Tus neeg uas muaj cov chromosomes tsim nyog rau lawv hom hu ua euploid; Hauv tib neeg, euploidy sib raug rau 22 khub ntawm autosomes thiab ib khub ntawm kev sib deev chromosomes.
Vim li cas Nondisjunction tshwm sim hauv chromosome 21?
Cov yam ntxwv ntawm chromosome 21 nondisjunction yog ib qho ntawm ntau yam ntawm tib neeg autosomes. Ntawd yog, feem ntau dhau los yog vim qhov ua yuam kev thaum lub sijhawm oogenesis: tsawg kawg 90% ntawm cov neeg mob chromosome 21 nondisjunction yog vim leej niam meiotic yuam kev [1], [2].
Tsis muaj kev cuam tshuam tshwm sim nyob qhov twg hauv lub voj voog ntawm tes?
Nondisjunction, uas chromosomes tsis sib luag, tuaj yeem tshwm sim hauv meiosis I (ib kab), meiosis II (kab ob), thiab mitosis (kab peb). Cov kev sib cais tsis sib xws no tuaj yeem tsim cov menyuam ntxhais nrog tus lej chromosome uas tsis tau xav txog, hu ua aneuploids.
