Qhov Tseem Ceeb Qhov txawv - Dominance vs Epistasis
Dominance thiab epistasis yog ob qhov xwm txheej uas piav qhia qhov tshwm sim ntawm cov phenotypes los ntawm cov noob. Dominance piav qhia txog qhov sib txawv ntawm cov noob caj noob ces cuam tshuam qhov kev qhia ntawm phenotype thiab qhov twg allele yog lub luag haujlwm rau qhov pom tau phenotype. Epistasis piav qhia txog kev sib raug zoo ntawm cov noob rau tib lub phenotype thiab yuav ua li cas alleles ntawm ib lub noob pab txhawb rau cov nyhuv ntawm phenotype ntawm lwm cov noob. Yog li ntawd, dominance piav qhia txog cov nyhuv npog ntawm cov alleles ntawm tib lub noob ntawm ib qho phenotype thaum epistasis piav qhia txog cov teebmeem ntawm ib lub noob ntawm phenotype ntawm lwm cov noob. Qhov no yog qhov sib txawv tseem ceeb ntawm kev tswj hwm thiab epistasis.
Dominance yog dab tsi?
Genes muaj ntau hom hu ua alleles. Feem ntau cov noob muaj ob lub alleles nyob rau ntawm homologous chromosomes. Kev sib raug zoo ntawm genotype thiab phenotype tuaj yeem piav qhia yooj yim vim yog kev koom tes ntawm tus kws tshawb fawb zoo Gregor Mendel thiab nws lub tswv yim ntawm kev tswj hwm. Raws li Mendel txoj kev xav, ob qho alleles raug xaiv nrog cov npe tseem ceeb ntawm allele thiab recessive allele. Piv txwv li, yog tias qhov siab ntawm cov txiv laum huab xeeb txiav txim siab los ntawm cov noob uas muaj ob qho alleles A thiab a, thiab yog tias cov genotypes AA, Aa thiab aA ua rau tib qhov siab, nws tuaj yeem xaus lus tias allele A yog qhov tseem ceeb rau tus cwj pwm thiab a yog recessive rau tus cwj pwm raws li qhia nyob rau hauv daim duab 01.
Daim duab 01: Mendel's Concept of Dominance
Txawm li cas los xij, dhau ntawm Mendel lub tswv yim, peb paub qee cov noob muaj nyob hauv ntau cov alleles thiab lawv tsis muaj peev xwm ua tiav lossis rov ua dua ib txwm. Yog li ntawd, lub tswv yim ntawm dominance tsis tuaj yeem siv tas li. Tsis tiav dominance thiab codominance yog ob qhov xwm txheej uas tsis tuaj yeem piav qhia los ntawm Mendel thawj txoj cai. Hauv kev tswj hwm tsis tiav, niam txiv tus cwj pwm tuaj yeem ib txwm sib xyaw hauv cov xeeb ntxwv heterozygous. Hauv codominance, ob leeg alleles ib txhij qhia nyob rau hauv cov xeeb ntxwv heterozygous.
Epistasis yog dab tsi?
Epistasis yog ib qho tshwm sim hauv cov noob caj noob ces piav qhia txog kev koom tes thiab kev sib raug zoo ntawm ob lossis ntau lub noob caj noob ces los txiav txim siab ib qho phenotype. Hauv lwm lo lus, epistasis tuaj yeem txhais tau tias yog kev sib cuam tshuam ntawm cov noob uas cov nyhuv ntawm ib qho allele ntawm cov noob cuam tshuam cov nyhuv ntawm alleles ntawm lwm cov noob. Piv txwv li, yog tias cov xim yog tsim los ntawm kev ua ntawm ob lub noob; gene 1 thiab gene 2, tsis muaj kev qhia ntawm ob lub noob, cov xim tsis tuaj yeem ua ke vim tias gene 1 yog lub luag haujlwm rau kev tsim cov khoom nruab nrab ntawm cov molecule precursor thiab nruab nrab yuav hloov mus rau hauv cov xim los ntawm kev qhia ntawm noob 2. Yog li ntawd, kev sib raug zoo ntawm ob lub noob yog xav tau rau qhov kawg ntawm cov xim uas muab cov phenotype. Qhov no yog hu ua epistasis. Epistasis kuj tseem siv tau los xa mus rau cov noob uas npog qhov cuam tshuam ntawm lwm cov noob.
Kev hloov ntawm ib lub noob lossis ob qhov kev hloov pauv ntawm cov noob loci tuaj yeem ua rau muaj qhov sib txawv ntawm cov phenotype. Epistasis tuaj yeem muab faib ua ntau hom xws li zoo epistasis, tsis zoo epistasis, antagonistic epistasis thiab synergistic epistasis raws li kev hloov pauv thiab qhov loj.
Daim duab 2: Epistasis noob ntawm cov plaub hau xim thiab baldness
Dab tsi yog qhov txawv ntawm Dominance thiab Epistasis?
Dominance vs Epistasis |
|
| Lub tswv yim ntawm kev tswj hwm yog siv rau cov alleles ntawm tib lub noob uas ib qho allele tseem ceeb thiab thib ob allele yog recessive | Epistasis yog hais txog kev sib raug zoo ntawm cov noob thiab piav qhia txog yuav ua li cas ib qho allele ntawm ib lub noob cuam tshuam rau phenotype ntawm lwm cov noob. |
| Phenotype | |
| Tus phenotype ntseeg tau tias yog tus cwj pwm dominance. | Tus phenotype tshwm sim los ntawm kev koom tes ntawm cov noob. |
Summary – Dominance and Epistasis
Dominance thiab epistasis yog ob lo lus siv hauv cov noob caj noob ces thaum piav txog cov phenotypes uas cuam tshuam rau alleles thiab cov kab lus ntawm noob. Dominant thiab recessive alleles yog ob versions ntawm ib tug noob. Lub allele uas yog lub luag haujlwm rau qhov tshwm sim ntawm phenotype yog lub npe hu ua allele dominant thiab hais tias yog tus cwj pwm tseem ceeb ntawm qhov phenotype. Epistasis yog ib qho tshwm sim uas tshwm sim ntawm cov noob thiab kev sib raug zoo ntawm cov noob yog lub luag haujlwm rau kev qhia txog qhov kawg phenotype. Alleles ntawm ib lub noob tuaj yeem cuam tshuam cov phenotype ntawm lwm cov noob. Ib qho kev hloov pauv hauv alleles ntawm ib lub noob yuav ua rau muaj qhov sib txawv phenotype tshaj qhov xav tau hauv epistasis. Qhov no yog qhov txawv ntawm dominance thiab epistasis.
