Isihloko: Imibuzo Yesibonelo kanye Nengxoxo Yeziphambano Ze-Monohybrid
I-Pendahuluan
I-Genetics iyigatsha lebhayoloji elifunda ukuthi izici zidluliselwa kanjani kusuka kwesinye isizukulwane kuya kwesinye. Umqondo oyisisekelo ku-genetics yi-monohybrid cross, okuyi-cross ehilela umbhangqwana owodwa wezimpawu ezahlukene. Kokubili okujabulisayo nokuyinselele, iziphambano ze-monohybrid zivame ukusetshenziselwa ukutadisha ukuthi ama-allele (izinhlobo ze-gene) asebenzisana kanjani ukuze kunqunywe izici zesidalwa. Kulesi sihloko, sizoxoxa ngezinkinga eziningana zezibonelo kanye nengxoxo yazo mayelana neziphambano ze-monohybrid.
Isibonelo Umbuzo 1: Ukuwela Izitshalo Ze-Pea
Isibonelo esivamile senhlanganisela ye-monohybrid ucwaningo lukaGregor Mendel ngezitshalo ze-pea. Kokunye ukuhlola, uMendel wahlanganisa isitshalo se-pea esinezimbali ezinsomi (UU) nesitshalo se-pea esinezimbali ezimhlophe (uu).
Umbuzo: Yiziphi izinhlobo ze-phenotypes kanye ne-genotypes zenzalo ye-F1 kanye ne-F2?
Ingxoxo:
– Isizukulwane se-F1:
UMendel wahlanganisa isitshalo esinezimbali ezinsomi (UU) nesitshalo esinezimbali ezimhlophe (uu). Ngenxa yalokhu kuhlukana, yonke inzalo ye-F1 izoba nohlobo lwe-genotype (Uu) ngoba yathola i-allele eyodwa ebusayo kumzali onezimbali ezinsomi kanye ne-allele eyodwa ebusayo kumzali onezimbali ezimhlophe. Ngenxa yokuthi i-allele ensomi (U) ibusayo, zonke izitshalo ze-F1 zizoba nohlobo lwe-phenotype olunsomi. Ngakho-ke, esizukulwaneni se-F1, zonke izitshalo zine-phenotype ensomi ene-genotype ye-heterozygous (Uu).
– Isizukulwane se-F2:
Uma izitshalo ze-F1 (Uu) zihlanganiswa, inzalo ye-F2 ephumayo inesilinganiso se-phenotypic esingu-3:1, ngokusekelwe esikweleni se-Punnett. Ukusatshalaliswa kwe-genotypic okuphumelayo kungu-1 UU: 2 Uu: 1 uu. Ngokuphathelene ne-phenotype, izitshalo ezintathu zizoba nezimbali ezinsomi kanti eyodwa izoba nezimbali ezimhlophe.
Ngakho-ke, uhlobo lwe-F2 luqukethe:
– 25% UU (i-homozygous eyinhloko)
– 50% Uu (heterozygous)
– 25% uu (i-homozygous recessive)
I-phenotype iqukethe:
– Izimbali ezinsomi ezingama-75% (UU kanye ne-Uu)
– 25% izimbali ezimhlophe (uu)
Isibonelo Umbuzo 2: Ukuwela Izilwane
Cabanga ngesimo sesiphambano kumagundane. Ake sithi i-allele yoboya obumnyama (B) inamandla ngaphezu kwe-allele yoboya obunsundu (b). Uma igundane eli-heterozygous (Bb) lihlanganiswa negundane eli-homozygous recessive (bb), kuzoba yini i-phenotype kanye ne-genotype yenzalo yabo?
Ingxoxo:
– Igundane lokuqala liyi-heterozygous ene-genotype (Bb), kanti igundane lesibili liyi-recessive homozygous ene-genotype (bb).
– Sisebenzisa isikwele sikaPunnett, singabona ukuhlanganiswa kwe-allele okungenzeka kwenzalo:
| | B | b |
|—|—-|—-|
| b | Bb | bb |
| b | Bb | bb |
– Izinhlobo zezakhi zofuzo ezingaba khona zenzalo yilezi:
– 50% Bb (heterozygous)
– 50% bb (i-homozygous recessive)
– Ngokuphathelene ne-phenotype:
– Ama-50% enzalo azoba noboya obumnyama (Bb)
– 50% bazoba noboya obunsundu (bb)
Isibonelo Umbuzo 3: Ukuzalelana Kwabantu
Kubantu, ake sithi i-allele yeminwe evamile (N) inamandla ngaphezu kwe-allele yeminwe eminingi (iminwe eyengeziwe) (n). Uma omunye umzali eyi-heterozygous yalesi sici kanti omunye umzali eyi-homozygous ye-recessive, iyini i-phenotype-to-genotype ratio yenzalo?
Ingxoxo:
– Abazali be-Heterozygous bane-genotype (Nn), kanti abazali be-homozygous abaphindaphindayo bane-genotype (nn).
– Sisebenzisa izikwele zePunnett, sithola:
| | N | n |
|—|—-|—-|
| n | Nn | nn |
| n | Nn | nn |
– Uhlobo lwenzalo luyi:
– 50% Nn (heterozygous)
– 50% nn (i-homozygous recessive)
– Uhlobo lwenzalo luthi:
– 50% iminwe evamile (Nn)
– 50% i-polydactyly (nn)
I-Kesimpulan:
Iziphambano ze-Monohybrid ziyithuluzi elibalulekile ekuqondeni izimiso zofuzo. Sisebenzisa izimiso eziyisisekelo njengokubusa kanye nokubuyela emuva, singabikezela ukusatshalaliswa kwezinhlobo ze-phenotype kanye ne-genotype ezizukulwaneni ezizayo. Isihluthulelo sokuqonda iziphambano ze-monohybrid ukuqaphela izimpawu zama-allele abusayo nawabuyela emuva kanye nokukwazi ukwakha nokuhlaziya izikwele ze-Punnett. Ukuzijwayeza njalo ngezibonelo ezahlukahlukene kuzoqinisa ulwazi lwethu lwezakhi zofuzo eziyisisekelo futhi kuthuthukise ukuqonda kwethu ukuthi izici zizuzwa kanjani njengefa.
