2024 Tus sau: Elizabeth Oswald | [email protected]. Kawg hloov kho: 2024-01-13 00:07
1 NONDISJUNCTION Nondisjunction Nondisjunction Feem ntau ntawm cov teeb meem tshwm sim los ntawm kev tsis sib txuas thaum lub sij hawm niam txiv meiosis I. Trisomy tshwm sim nyob rau hauv tsawg kawg yog 0.3% ntawm cov menyuam mosthiab nyob rau hauv ze li ntawm 25% ntawm spontaneous rho menyuam. Nws yog qhov ua rau muaj kev cuam tshuam ntawm cev xeeb tub thiab yog feem ntau paub tias ua rau muaj kev puas hlwb. https://en.wikipedia.org › wiki › Nondisjunction
Nondisjunction - Wikipedia
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 cell. Qhov no feem ntau tshwm sim hauv meiosis, tab sis nws yuav tshwm sim hauv mitosis los tsim ib tus neeg mosaic.
Yuav ua li cas thaum homologous chromosomes tsis sib cais?
Aneuploidy yog tshwm sim los ntawm nondisjunction, uas tshwm sim thaum khub ntawm homologous chromosomes lossis tus muam chromatids tsis sib cais thaum lub sijhawm meiosis. Kev poob ntawm ib qho chromosome los ntawm diploid genome hu ua monosomy (2n-1), thaum qhov nce ntawm ib chromosome hu ua trisomy (2n + 1).
Thaum ib homologous chromosome tsis cais thaum lub sij hawm meiosis Qhov no hu ua?
Nondisjunction. Nondisjunction yog qhov ua tsis tiav ntawm homologous chromosomes (chromatids) kom sib cais kom zoo thaum lub sij hawm meiotic cell division.
Thaum chromosomes tsis cais nws hu ua?
Nondisjunction yog qhov ua tsis tiav ntawm chromosomes cais, uas tsim tau tus ntxhaiscov hlwb nrog cov lej txawv txav ntawm chromosomes. [
Pob homologous chromosomes cais?
In anaphase I, centromeres tawgthiab homologous chromosomes cais. Hauv telophase I, chromosomes txav mus rau cov ncej; Thaum lub sij hawm cytokinesis lub cell sib cais ua ob lub hlwb haploid.
Pom zoo:
Lub sijhawm prophase ib khub homologous ntawm chromosomes muaj?
Cov lus teb raug: Cov chromosomes homologous muaj ob chromosomes thiab plaub chromatids nyob rau theem prophase. Yuav ua li cas rau chromosomes thaum lub sij hawm prophase? Thaum lub sijhawm prophase, qhov nyuaj ntawm DNA thiab cov proteins uas muaj nyob hauv cov nucleus, hu ua chromatin, condenses.
Yuav tsum ua kom homologous chromosomes khub?
Lub homologous chromosomes nyob rau hauv lub cell yuav tsis ua khubthiab tau txais kev tshuaj ntsuam genetic recombination nrog ib leeg. Vim li cas homologous chromosomes khub? Lub homologous chromosomes nyob rau hauv lub nucleus ntawm lub cev gamete khub thaum lub sij hawm meiosis.
Lub sijhawm meiosis homologous khub ntawm chromosomes?
Ua ntej cov kab mob nkag mus rau meiosis, lawv feem ntau yog diploid, txhais tau tias lawv muaj ob daim ntawv luam ntawm txhua tus chromosome. Tom qab ntawd, ua ntej cov kab mob nkag mus rau hauv meiosis, nws duplicates nws DNA kom lub cell muaj plaub DNA luam tawm ntawm ob khub ntawm homologous chromosomes.
Thaum meiosis kuv cov homologous chromosomes ntawm tetrad?
Thaum lub sijhawm meiosis I, homologous chromosomes ntawm txhua khub tuaj ua ke thiab ua ib sab ntawm ib sab hauv qhov xwm txheej hu ua synapsis. Synapsis tshwm sim hauv tetrad, ib qho kev koom ua ke ntawm plaub chromatids(ob homologous chromosomes uas muaj ob chromatids txhua).
Puas yuav homologous chromosomes khub thaum meiosis?
Homologous chromosomes tsis ua haujlwm zoo ib yam hauv mitosis li lawv ua hauv meiosis. Ua ntej txhua tus mitotic faib ib lub xovtooj mus, cov chromosomes hauv niam txiv cell rov ua dua lawv tus kheej. Lub homologous chromosomes nyob rau hauv lub cell yuav ib txwm tsis ua khubthiab tau txais genetic recombination nrog ib leeg.
