Yuav ua li cas yog tias homologous chromosomes tsis ua khub?
Yuav ua li cas yog tias homologous chromosomes tsis ua khub?

Video: Yuav ua li cas yog tias homologous chromosomes tsis ua khub?

Video: Yuav ua li cas yog tias homologous chromosomes tsis ua khub?
Video: Nrauj koj tag ces luag tej ntxub by tub vwj 6/22/2019 2024, Kaum ib hlis
Anonim

Anuploidy yog tshwm sim los ntawm nondisjunction, uas tshwm sim thaum khub ntawm homologous chromosomes los yog tus muam chromatids tsis cais thaum lub sij hawm meiosis. Yog homologous chromosomes tsis cais thaum lub sij hawm meiosis kuv, qhov tshwm sim yog tsis muaj gametes nrog tus lej ib txwm (ib qho) ntawm chromosomes.

Tsis tas li ntawd, yuav ua li cas yog tias chromosomes tsis cais kom raug?

Nondisjunction tsim cov Gametes txawv txav Yog kev tsis sib haum xeeb tshwm sim thaum lub sij hawm anaphase I ntawm meiosis kuv, qhov no txhais tau hais tias tsawg kawg yog ib khub ntawm homologous chromosomes tsis tau cais . Qhov kawg tshwm sim yog ob lub hlwb uas muaj ib daim ntawv ntxiv ntawm ib qho chromosome thiab ob lub hlwb uas ploj lawm chromosome.

Kuj Paub, yuav muaj dab tsi tshwm sim yog tias ib qho ntawm cov chromosomes hauv ib khub homologous tsis tau cais tawm ntawm nws homologue thaum kawg ntawm metaphase 1? Downs syndrome yog tshwm sim los ntawm muaj 3 daim ntawv chromosome 21. Yuav kom tsim tau qhov tshwm sim, los ntawm homologous khub ua tsis tau tejyam sib cais los yog cov duplicates hauv Meiosis II tsis cais.

Kuj nug, vim li cas nws tseem ceeb heev uas homologous chromosomes khub kom raug thaum meiosis?

Muaj nuj nqi. Homologous chromosomes yog tseem ceeb nyob rau hauv cov txheej txheem ntawm meiosis thiab mob mitosis . Lawv tso cai rau recombination thiab random segregation ntawm genetic khoom los ntawm leej niam thiab leej txiv mus rau hauv lub hlwb tshiab.

Dab tsi yog kev sib koom ua ke ntawm homologous chromosomes hu ua?

Synapsis (ib hu ua syndesis) yog ua khub ntawm ob homologous chromosomes uas tshwm sim thaum meiosis. Nws tso cai rau kev sib piv ntawm homologous khub ua ntej lawv cais, thiab ua tau chromosomal crossover ntawm lawv. Synapsis tshwm sim thaum lub sij hawm prophase I ntawm meiosis.

Pom zoo: