Isihloko: Isibonelo Semibuzo Yengxoxo Ephikisanayo Ye-Dihybrid
I-Pengantar
Igama elithi "dihybrid" libhekisela ekuhlanganiseni abantu ababili abahlukile ezicini ezimbili noma izakhi zofuzo ezithandekayo, kanti isici ngasinye sinezinhlobo ezimbili ezingenzeka. Ukuwela kwe-Dihybrid kuwumqondo oyisisekelo ku-genetics yaseMendelian, okusisiza siqonde ukuthi izici zidluliselwa kanjani ezizukulwaneni ngezizukulwane. Lesi sihloko sizogxila kakhulu ekuhlanganiseni kwe-dihybrid ngokunikeza izibonelo nezingxoxo.
Ukuqonda iziphambano ze-Dihybrid
Isiphambano se-dihybrid sigxila ezicini ezimbili ezihlukene. Isici ngasinye silawulwa yizimbili zezi-allele ezingaba yizidlakela noma eziphindaphindayo. Isiphambano se-dihybrid sihilela abazali aba-heterozygous ngezici ezimbili ezihlukene futhi sihlola ukusatshalaliswa kwalezo zi-allele kubantwana babo.
Izimiso Eziyisisekelo Zemithetho KaMendel
1. Umthetho Wokuhlukaniswa: Ama-allele esici esithile noma i-gene azohlukana noma ahlukanise ngokungahleliwe ngesikhathi sokwakheka kwe-gamete, ukuze i-gamete ngayinye ibe ne-allele eyodwa kuphela kubhangqa ngalinye le-allele.
2. Umthetho Wokuhlukaniswa Okuzimele: Ama-allele ezakhi zofuzo ezahlukene azozuzwa ngokuzimela komunye nomunye, okusho ukuthi ukusatshalaliswa kwe-allele eyodwa akuthinti ukusatshalaliswa kwenye i-allele - ngaphandle kokuthi izakhi zofuzo zixhunywe ngokomzimba ku-chromosome efanayo.
Isakhiwo se-Genotype kanye ne-Phenotype
Esixukwini se-dihybrid, sivame ukubhekana nezinhlanganisela ezine ze-gamete ezingaba khona, ikakhulukazi uma abazali beyi-heterozygous kuzo zombili lezi zici. Lokhu kusho ukuthi sibhekene nesimo esiyinkimbinkimbi kakhulu sokusebenzisana kwe-allelic kunasesixukwini esisodwa se-monohybrid, esigxile ku-gene eyodwa kuphela.
Ifomula Yokunquma Inani Lama-Gametes
Uma umuntu ngamunye eyi-AaBb, khona-ke singasebenzisa umthetho we-assets ezimele ukuze sinqume inani lama-gametes ngokuphindaphinda amathuba e-allele pair ngayinye, sithole umphumela ongu-2 x 2 = izinhlobo ezi-4 ezahlukene zama-gametes, okungukuthi i-AB, i-Ab, i-aB, kanye ne-ab.
Isibonelo semibuzo ye-Dihybrid Cross
Umbuzo 1: Ukuzalisana Phakathi Kwezitshalo Ezimbili Zama-Pea
Izitshalo ze-pea zine-alleles eziyindilinga (R) kanye nezinemibimbi (r), kanye nombala ophuzi (Y) noma oluhlaza (y). Izitshalo ezimbili, ngasinye sine-heterozygous kuzo zombili izici (RrYy), ziyahlanganiswa. Yiziphi izilinganiso ze-phenotypic ezingaba khona?
Izinyathelo Zesixazululo:
1. Thola ama-Gamete kubazali: Ngenxa yokuthi womabili angama-heterozygous (RrYy), singathola izinhlobo ezine zama-gamete kulelo nalelo, okungukuthi: i-RY, i-Ry, i-ry.
2. Ukusebenzisa i-Punnett Square: Ngokufaka wonke ama-gametes angaba khona ku-4×4 Punnett Square, singakwazi ukuthola izinhlobo zofuzo ezingaba khona zenzalo.
3. Yakha i-Genotype kanye ne-Phenotype:
– I-Genotype Eyindilinga-Ephuzi (R_Y_) i-RY kanye nezinye ezihlanganisa yona.
– I-Phenotype ye-Ry-Green (R_yy) Genotype yi-Ry kanye nenhlanganisela engakhiqiza lokhu.
– Uhlobo lwe-genotype olunemibimbi-ophuzi (rrY_) luyi-rY kanye nezinhlanganisela ezihambisana nalo.
– Uhlobo lwe-Genotype olunemibimbi-oluhlaza (rryy) luyi-ry kanye nezinhlanganisela zalo ezihambisana nalo.
4. Bala imvamisa ye-Phenotype:
– Bala wonke amabhokisi amakhulu ukuze ubikezele imvamisa ye-phenotypic.
– Ekugcineni, uthola isilinganiso se-Mendelian esivamile se-dihybrid cross: 9:3:3:1.
Ngakho-ke isilinganiso se-phenotypic esitholakala kulesi siphambano singu-9 Ophuzi Oyindilinga: 3 Oluhlaza Okwesibhakabhaka: 3 Ophuzi Owesibhakabhaka Owemibimbi: 1 Oluhlaza Owesibhakabhaka Owemibimbi.
Umbuzo 2: Imbewu Yokuzalanisa Yezinye Izitshalo
Isitshalo sinezimbali ezibomvu (A) ezivelele ngaphezu komhlophe (a) kanti ukuphakama kwesitshalo (T) kuvelele ngaphezu kobufushane (t). Uma isitshalo esihlangene i-AaTt sihlanganiswa nesitshalo se-aatt, kuyoba yini umphumela we-F1?
Izinyathelo Zesixazululo:
1. Chaza ama-Gametes Abazali:
– I-gamete yesitshalo sokuqala (i-AaTt) yi-AT, At, aT, noma i-at.
– I-gamete yesitshalo sesibili (aatt) i-at.
2. Dala Umdwebo Ophambene:
- Hlanganisa ama-gametes angaba khona avela kumzali ngamunye usebenzisa i-Punnett Square 4×1.
– Kufanele uhlole inhlanganisela etholakala.
3. Thola ukuhlanganiswa kwe-Genotype kanye ne-Phenotype:
– Thola isilinganiso se-phenotype okuhlanganisa:
– AT-: Okubomvu-Okuphezulu
– aaT-: Okumhlophe-Okuphezulu
– A-tt: Okubomvu-Okufushane
– i-aatt: Okumhlophe-Okufushane
4. Bala Ukusatshalaliswa kwe-Phenotypic kanye ne-Genotypic:
– Thola isilinganiso ngokusekelwe ekuhlanganisweni kwezinhlobo zezakhi zofuzo okungenzeka.
Umphumela uba ngu-1 Obomvu-Omude: 1 Obomvu-Omfushane: 1 Omhlophe-Omude: 1 Omhlophe-Omude.
Isiphetho
Iziphambano ze-Dihybrid zinikeza ukuqonda okujulile ngokuthi izakhi zofuzo ezahlukene zizuzwa kanjani futhi zibonakaliswa kanjani enzalweni. Ngokuqonda imithetho kaMendel yokuhlukaniswa kanye nokuhlukaniswa okuzimele, singalindela imiphumela yeziphambano ezahlukene. Ukuzijwayeza ngezinkinga eziyisibonelo, njengalezo ezichazwe ngenhla, kuyisihluthulelo sokuqonda okuningiliziwe kwale mibono kanye nokusetshenziswa kwayo emaqinisweni ezakhi zofuzo zezitshalo noma zezilwane. Yiqiniso, lokhu kumane nje kuyisiqalo sokuhlola okuyinkimbinkimbi kakhulu kokuhlukahluka kwezakhi zofuzo kanye nokusebenzisana phakathi kwezakhi zofuzo ezintweni eziphilayo.
