Qhov sib txawv tseem ceeb ntawm kev taw qhia random thiab kev ywj pheej assortment yog qhov random orientation yog random kab ntawm homologous chromosome khub ntawm tus kab zauv thaum lub sij hawm metaphase ntawm meiosis 1 thaum ywj siab assortment yog hais txog cov qub txeeg qub teg ntawm cov noob ntawm nws tus kheej los ntawm cov qub txeeg qub teg. lwm yam noob.
Cell divisions ua rau cov noob qes tshiab los yog cov qe qe (gametes). Mitosis tshwm sim nyob rau hauv cov noob caj noob ces zoo tib yam thaum meiosis tshwm sim hauv gametes uas txawv ntawm caj ces. Thaum lub sij hawm metaphase ntawm meiosis, homologous chromosome khub (ib qho los ntawm leej niam thiab lwm tus los ntawm leej txiv) kab ntawm kab zauv raws li bivalents. Kev taw qhia ntawm txhua khub ntawm homologous chromosomes yog random. Nws tsis cuam tshuam los ntawm kev taw qhia ntawm lwm tus khub homologous. Qhov no yog hu ua random orientation. Raws li qhov tshwm sim ntawm random orientation, chromosomes cais ntawm ib leeg ntawm nws tus kheej thaum lub sij hawm anaphase. Vim li ntawd, alleles ntawm chromosomes kuj cais nws tus kheej. Yog li ntawd, kev sib cais ntawm alleles ntawm chromosomes ntawm nws tus kheej los ntawm ib qho allele ntawm lwm chromosome yog hu ua ywj siab assortment.
Yam kev taw qhia Random yog dab tsi?
Ib homologous chromosome khub muaj xws li ib leej niam thiab ib leej txiv chromosome. Cov khub no yog tib yam loj, zoo li qub thiab nqa tib lub noob, tab sis lawv tsis yog caj ces zoo ib yam. Thaum lub sij hawm metaphase ntawm meiosis 1, homologous khub kab nyob rau ntawm kab zauv. Txoj kev lineup no tshwm sim random. Kev taw qhia ntawm homologous chromosome khub yog ywj siab thiab tsis cuam tshuam los ntawm kev taw qhia ntawm ib khub homologous chromosome. Yog li ntawd, nws yog hu ua random orientation. Muaj ob qhov ua tau random orientations ntawm homologous chromosome khub ntawm kab zauv.
Daim duab 01: Pair of Homologous Chromosomes
Nyob rau hauv cov txheej txheem lineup, homologous chromosomes tsim ib tug nruj khub hu ua synapsis. Hauv synapsis, cov noob ntawm cov chromatids ntawm homologous chromosomes tau ua raws li ib leeg, pab txhawb thiab txhawb kev hla thiab caj ces recombination. Li no, qhov kev taw qhia random ntawm homologous chromosomes yog lwm lub tswv yim uas qhia txog kev hloov pauv mus rau gametes lossis spores.
Kev ywj pheej yog dab tsi?
Txoj cai ntawm kev ywj pheej yog ib qho ntawm peb txoj cai ntawm Gregor Mendel. Nws piav qhia yuav ua li cas alleles los yog noob cais nws tus kheej ntawm ib leeg thaum lub sij hawm gamete tsim. Hauv cov lus yooj yooj yim, kev ywj pheej assortment yog qhov qub txeeg qub teg ntawm cov noob ntawm nws tus kheej los ntawm qhov qub txeeg qub teg ntawm lwm cov noob.
Daim duab 02: Kev ywj pheej Assortment
A gamete tau txais ib qho allele yam tsis muaj kev cuam tshuam ntawm lwm tus allele. Yog li ntawd, cov alleles tau dhau los ntawm niam txiv mus rau cov xeeb ntxwv ntawm nws tus kheej. Independent assortment yog lig vim qhov kev taw qhia random ntawm homologous chromosomes. Yog hais tias cov noob tau sib txuas tag nrho, cov alleles tsis tso tawm kev ywj pheej. Lawv zoo li yuav tau txais qub txeeg qub teg ua ke.
Dab tsi yog qhov zoo sib xws ntawm Random Orientation thiab Independent Assortment?
- Kev ywj pheej yog vim qhov sib txawv ntawm cov khub ntawm homologous chromosomes hauv meiosis I.
- Ob qho xwm txheej tseem ceeb heev hauv kev tsim cov caj ces sib txawv.
- Raws li qhov tshwm sim ntawm ob qho xwm txheej, gametes tau txais kev sib xyaw ua ke ntawm chromosomes thiab ib qho tshwj xeeb ntawm cov noob.
- Kev hloov pauv caj ces hauv cov xeeb ntxwv yog vim cov xwm txheej no tshwm sim hauv meiosis.
Qhov txawv ntawm Random Orientation thiab Independent Assortment yog dab tsi?
Random orientation yog txoj kab sib txuas ntawm homologous chromosome khub ntawm cell equator thaum qhov kev sib txawv ntawm cov noob caj noob ces nws tus kheej los ntawm cov qub txeeg qub teg ntawm lwm cov noob. Yog li, qhov no yog qhov sib txawv tseem ceeb ntawm kev taw qhia random thiab kev ywj pheej assortment.
Cov hauv qab no infographic qhia txog qhov sib txawv ntawm qhov kev taw qhia random thiab kev ywj pheej assortment.
Summary – Random Orientation vs Independent Assortment
Meiosis ua rau tsim cov genetic cim gametes. Qhov no tshwm sim vim qhov kev taw qhia random ntawm homologous chromosome khub thiab kev ywj pheej ntawm cov noob / alleles. Homologous chromosome khub kab ntawm lub phaj metaphase randomly. Yog li ntawd, chromosomes cais nws tus kheej ntawm ib leeg. Thaum chromosomes cais nws tus kheej, alleles lossis cov noob ntawm cov chromosomes cais los yog tau txais los ntawm gametes ntawm nws tus kheej. Qhov no yog cov txheej txheem ntawm kev ywj pheej assortment. Yog li, qhov no yog cov ntsiab lus ntawm qhov sib txawv ntawm random orientation thiab ywj siab assortment. Ob qho xwm txheej no ua rau muaj qhov tshwj xeeb ntawm alleles lossis cov noob hauv gametes thaum kawg ntawm meiosis.
