Nondisjunction, uas chromosomes tsis cais sib npaug, 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.
Puas yog kev tsis sib haum xeeb ntau dua hauv mitosis lossis meiosis?
1 NONDISJUNCTION
Nondisjunction txhais tau hais tias ib khub ntawm homologous chromosomes tau ua tsis tiav los yog cais ntawm anaphase kom ob leeg chromosomes ntawm khub dhau mus rau tib tus ntxhais cell. Qhov no tej zaum yuav tshwm sim feem ntau hauv meiosis, tab sis nws yuav tshwm sim hauv mitosis los tsim ib tus neeg mosaic.
Puas muaj kev tsis sib haum xeeb hauv meiosis?
Nondisjunction tuaj yeem tshwm sim thaum anaphase ntawm 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.
Dab tsi yog kev tsis sib haum xeeb thiab thaum twg hauv meiosis tuaj yeem tshwm sim?
Nondisjunction tshwm sim thaum homologous chromosomes lossis tus muam chromatids tsis cais thaum lub sijhawm meiosis, ua rau tus lej chromosome txawv txav. Kev tsis sib haum xeeb yuav tshwm sim thaum meiosis I lossis meiosis II.
Qhov tshwm sim ntawm kev tsis sib haum yog dab tsi?
Nondisjunction: Ua tsis tiav ntawm cov chromosomes sib cais (kom disjoin) thaum lub sijhawm faib ntawm tes, kom ob qho tib si chromosomes mus rau ib tus ntxhais cell thiab tsis mus rau lwm tus. Nondisjunction ua rau yuam kev hauv chromosome tooj, xws li trisomy 21 (Down syndrome) thiab monosomy X (Turner syndrome).
