Qhov sib txawv tseem ceeb ntawm tus muam thiab cov tsis muaj tus chromatids yog tus muam chromatids zoo ib yam thiab muaj tib lub allele nyob rau hauv tib loci thaum nonsister chromatids tsis zoo tib yam thiab muaj cov alleles ntawm tib lub noob nyob rau hauv tib loci.
Ob hom chromatids pom nyob rau hauv lub cell uas dhau los ntawm cell division yog tus muam chromatids thiab nonsister chromatids. Feem ntau, chromatids tsim thaum ntxov ntawm kev faib cell. Ntawm qhov tod tes, nonsister chromatids tsim thaum metaphase I ntawm meiosis. Lawv muaj nyob rau hauv homologous chromosome khub ntawm cell equator thaum tus muam chromatids muaj nyob rau hauv tib chromosome. Ntxiv mus, lub centromere ntawm chromosome koom nrog ob tug muam chromatids ua ke.
Sister Chromatids yog dab tsi?
Muam chromatids yog ob lub chromatids replicated ntawm ib chromosome koom ua ke los ntawm ib tug centromere. Sister chromatids replicate ntawm S theem ntawm interphase thaum DNA replication. Qhov tseem ceeb, ob tus muam chromatids muaj tib qho allele hauv tib loci. Ntxiv mus, tus muam chromatids ntawm tib chromosome coj txawv txawv hauv mitosis thiab meiosis.
Thaum lub sijhawm metaphase ntawm mitosis, tus neeg chromosomes sib dhos ntawm lub xovtooj ntawm tes hauv txoj kev uas ob tus viv ncaus chromatids faib dua li lub phaj metaphase lossis kab zauv. Tom qab ntawd, lub centromere sib cais thiab ob tus muam chromatids sib cais los ntawm ib leeg thiab sib nrug thaum lub sij hawm anaphase. Yog li ntawd, cov viv ncaus chromatids sib cais txav mus rau cov ncej sab nraud.
Daim duab 01: Muam Chromatids
Ntxiv mus, thaum lub sij hawm metaphase I ntawm meiosis I, homologous chromosomes khub ua ke ntawm lub cell equator. Tom qab ntawd thaum lub sij hawm anaphase I, homologous chromosomes sib cais los ntawm ib leeg yam tsis muaj kev sib cais ntawm lub centromere. Yog li, tus muam chromatids tseem nyob twj ywm thaum lub sij hawm anaphase I ntawm meiosis. Tab sis, thaum lub sij hawm metaphase II ntawm meiosis II, tus neeg chromosomes (replicated) nyob rau hauv lub cell equator. Thaum lub sij hawm anaphase II, centromeres sib cais, thiab tus muam chromatids tau sib cais dua li hauv mitosis. Yog li ntawd, ib leeg-poj niam txiv neej cell yuav muaj ib tug viv ncaus chromatid los ntawm txhua chromosome.
Dab tsi yog Chromatids?
Nonsister chromatids yog chromatids nyob rau hauv txhua chromosome ntawm ib homologous chromosome khub. Hauv genome, txhua tus chromosome nrog tus lej diploid (2n) chromosome muaj lwm homologous chromosome. Txhua homologous chromosome tau txais los ntawm txhua tus niam txiv. Yog li ntawd, nonsister chromatids tsis zoo ib yam vim lawv tau txais los ntawm ob niam txiv.
Daim duab 02: Tsis yog Chromatids
Nonsister chromatids muaj cov alleles ntawm tib lub noob ntawm tib loci. Kev sib koom ua ke ntawm ob homologous chromosomes tshwm sim thaum lub sijhawm metaphase I ntawm meiosis. Txij li thaum lawv yog tib qhov ntev, tib cov noob ntawm qhov chaw tshwj xeeb, tib lub qauv staining thiab tib txoj haujlwm centromere, nonsister chromatids kuj raug xa mus rau homologous. Nonsister chromatids feem ntau koom nrog kev sib deev. Qhov tseem ceeb tshaj plaws, kev hla dhau thiab kev sib txuas ntawm caj ces tshwm sim ntawm nonsister chromatids. Yog li, nws ua rau muaj kev sib txawv ntawm caj ces hauv gametes. Yog li ntawd, nws yog ib qho tseem ceeb ntawm evolutionary txheej txheem.
Dab tsi zoo sib xws ntawm Sister thiab Nonsister Chromatids?
- Ob tus viv ncaus thiab cov tsis muaj tus kabmob chromatids yog tsim thaum lub sijhawm rov ua dua ntawm DNA.
- Lawv ob leeg tshwm sim ua khub.
- ALso, ob tus viv ncaus thiab cov neeg tsis muaj npe chromatids muaj alleles ntawm tib lub noob. Sister chromatids muaj tib alleles wile nonsister chromatids muaj cov alleles.
- Dhau li ntawd, ob hom chromatids cais ntawm ib leeg thaum lub sijhawm faib cell.
Qhov txawv ntawm Sister thiab Nonsister Chromatids yog dab tsi?
Muaj ob hom chromatids pom thaum lub sijhawm faib ntawm tes uas yog tus muam chromatids thiab nonsister chromatids. Muam chromatids yog cov chromatids ntawm tib chromosome uas tau sib cais los ntawm centromere thiab muaj tib alleles ntawm tib loci. Ntawm qhov tod tes, nonsister chromatids yog cov chromatids ntawm homologous chromosome khub uas muaj cov alleles ntawm tib lub noob ntawm tib loci. Yog li ntawd, qhov sib txawv tseem ceeb ntawm tus muam thiab cov tsis muaj menyuam chromatids yog cov viv ncaus chromatids zoo ib yam thaum uas tsis yog tus menyuam chromatids tsis zoo ib yam.
Tsis tas li ntawd, tus muam chromatids tshwm sim ntawm qhov cuam tshuam ntawm kev faib tawm ntawm tes thaum cov chromatids nonsister tshwm nyob rau ntawm metaphase I ntawm meiosis I. Yog li, nws kuj yog qhov sib txawv ntawm tus muam thiab cov chromatids nonsister. Tsis tas li ntawd, lwm qhov sib txawv ntawm tus viv ncaus thiab cov chromatids uas tsis yog tus menyuam yog qhov kev hla dhau los ntawm qhov tsis sib xws ntawm chromatids thaum nws tsis pom ntawm tus muam chromatids. Qhov tseem ceeb tshaj plaws, kev sib pauv ntawm cov khoom siv caj ces tshwm sim ntawm nonsister chromatids thaum sib pauv cov khoom siv caj ces tsis tshwm sim ntawm tus muam chromatids. Yog li ntawd, nws kuj yog qhov sib txawv ntawm tus muam thiab tsis yog tus chromatids.
Hauv qab infographic ntawm qhov sib txawv ntawm tus viv ncaus thiab cov tsis muaj npe chromatids piav qhia qhov txawv no.
Summary – Sister vs Nonsister Chromatids
Muam chromatids yog ob lub chromatids replicated ntawm ib chromosome koom ua ke los ntawm ib tug centromere. Ntawm qhov tod tes, nonsister chromatids yog chromatids nyob rau hauv sib txawv chromosomes ntawm ib tug homologous chromosome khub. Qhov sib txawv tseem ceeb ntawm tus viv ncaus thiab cov chromatids uas tsis yog tus menyuam yog cov viv ncaus chromatids muaj tib lub allele nyob rau hauv tib loci thaum nonsister chromatids muaj cov alleles ntawm tib cov noob hauv tib loci. Txawm li cas los xij, ob tus viv ncaus thiab cov tsis muaj npe chromatids muaj xws li tib yam lossis sib txawv ntawm cov noob ntawm tib loci. Muam chromatids nyob ntawm tib chromosome. Li no, lawv yog cov ntawv luam tib yam. Tab sis, nonsister chromatids nrhiav nyob rau hauv ib tug homologous chromosome khub los ntawm txhua leej niam txiv li no lawv tsis zoo tib yam. Qhov no yog cov ntsiab lus ntawm qhov sib txawv ntawm tus muam thiab tsis yog tus chromatids.
