Yuav ua li cas yog ob-hybrid crossover

Cov kev cai ntawm qub txeeg qub teg Mendel rau monohybrid ntoo khaub lig fwm nyob rau hauv cov ntaub ntawv ntawm ntau ob-hybrid. Nyob rau hauv no hom ntawm kev sis raug zoo niam txiv ntaub ntawv txawv los ntawm ob khub ntawm contrasting yam ntxwv.

Xav txog cov piv txwv ntawm Mendel dihybrid ntoo khaub lig thiab txoj kev pom kev cai. Hla ob ntawm ntau yam taum mog: nrog dawb paj thiab ib tug qub ntug thiab ntshav paj thiab elongated ntug. Tag nrho cov thawj-tiam neeg muaj qub dawb paj nrog ib tug whisk. Los ntawm no peb xaus uas lub dawb xim (denoted los ntawm C) thiab lub cev ntev (sau E) - yog cov tseem ceeb nta ib tug liab doog xim (s) thiab ib tug elongate whisk (e) - recessive. Thaum nws tus kheej-pollination ntawm cov thawj tiam ntawm cov nroj tsuag yog phua. Rau lub hom phiaj ntawm clarity rau hla tswvyim.

Thawj tus ntoo khaub lig: P1 x CCEE CCEE

G 2Ss thiab 2Ee

F1 CCEE

Qhov thib ob pos (selfing F1 hybrids) P2 x CCEE CCEE. Dihybrid ntoo khaub lig mus rau tsim 16 hom ntawm zygotes. Txhua gamete yuav muaj ib tug neeg sawv cev los ntawm noob officers nrog P-thiab E-E officers. Thaum zoo li no noob C nrog sib npaug muaj tseeb yuav muab tag nrho nrog E los yog e nyob rau hauv lem, thiab yuav muab nrog E los yog e Cov uas ua hybrid CCEE ntaub ntawv nrog sib npaug zaus ntawm gamete hom 4: .. CE, GE, Ce, ce. Obedin ua ke, lawv thiaj muaj tus kab mob: 9 nrog rau tej dawb Corolla, nrog 3 dawb elongate whisk 3 nrog ib tug ib txwm ntug magenta thiab magenta 1 nrog ib tug elongated ntug.

Nyob rau hauv lub thib ob tiam ntawm hla hybrids sib nrug, outwardly zoo xws li cov niam txiv ntaub ntawv, duab yog tsim nrog ib tug tshiab ua ke ntawm cov cim (combinative los yog caj ces variability). Qhov no tshwm sim ua ib qho tseem ceeb luag hauj lwm nyob rau hauv lub evolution ntawm yields tshiab ob peb ua ke ntawm adaptive sijhawm. Tsis tas li ntawd koom siv nyob rau hauv yug me nyuam rau, qhov twg crossbreeding ntawm cov nroj tsuag thiab tsiaj txhu nce ntau ntau yam thiab breeds ua rau nws tau los ua kom paub tshiab hom.

Tus nab npawb ntawm phenotypes nyob rau hauv F2 yog tsawg tshaj li tus naj npawb ntawm cov genotypes. Qhov no yog vim lub fact tias lub union ntawm txawv gametes yuav muab tib lub morphological yam ntxwv. Yog li ntawd, peb tau cov splitting hauv lub phenotype - 9: 3: 3: 1.

Qhov no ob-hybrid crossover yog sai tau yog tias lub hom noob nyob rau hauv nonhomologous chromosomes. Cytological hauv paus ntawm xws li ib tug merger thiab rov - meiosis thiab fertilization. Mendel pom tias nrog xws li kev sis raug zoo ntawm cov noob txhua khub cwj pwm pub nws tus kheej ntawm ib leeg, dawb do raug ua ke nyob rau hauv tag nrho cov tau ob peb ua ke (sab nraud qub txeeg qub teg).

Tag nrho cov qauv ntawm qub txeeg qub teg uas Mendel teem rau ib thiab ob-hybrid pos, yam ntxwv ntawm ntau ob peb ua ke. Yog li ntawd, poligibridnoe hla tshwm sim thaum kab mob yog npaum li cas rau qhov no distinguished peb lossis ntau tshaj contrasting nta. Hauv plawv ntawm no fusion ntawm gametes thiab cov redistribution ntawm kev tshuaj ntsuam genetic ntaub ntawv yog cov kev cai ntawm kev zom thiab ywj siab ntawm qub txeeg qub teg.

Los ntawm cov foregoing, peb xaus uas lub ob-hybrid crossover - yog, nyob rau hauv qhov tseeb, ob ntawm nws tus kheej-xeeb zoo tib yam hla, nyob qhov twg muaj ib tug lwm txoj kos npe rau yog muab rau tus account (monohybrid). Qhov no yog muaj tseeb rau cov nroj tsuag thiab tsiaj txhu.