Ukulawulwa okungaphelele kungumphumela wokusebenzisana kwezinselele zesiginja esisodwa

Ukubusa okungaphelele kuyindlela ekhethekile yokusebenzisana kwezakhi zofuzo, lapho umkhuba obuthakathaka obuthakathaka khona ongeke ususwe ngokuphelele. Ngokuhambisana nokujwayelekile okutholakala nguG. Mendel, isibonakaliso esiqakathekileko sithintela ngokuphelele ukubonakaliswa okuphindaphindiwe. Umcwaningi wafunda ukuveza izibonakaliso ezihlukile ezitshalweni ngokubonakaliswa kwezinselele eziphezulu noma eziphindaphindiwe. Kwezinye izimo, uMendel wabhekana nokuhluleka ukuhambisana nale iphethini, kodwa akazange amnike incazelo.

Ifomu elisha lefa

Ngezinye izikhathi, ngenxa yokuwela, inzalo izuzwe njengezici eziphakathi ezingazange zinikeze isakhi sofuzo kwifomu le-homozygous. Ukulawulwa okungaphelele akukona kudivayisi yezinhloso zomzimba kuze kube sekuqaleni kwekhulu lama-XX, lapho imithetho kaMendel iphinda ithola khona. Ngesikhathi esifanayo, ososayensi abaningi basokwemvelo bahlolisisa izakhi zezitshalo nezilwane (utamatisi, i-legumes, ama-hamsters, amagundane, izimpukane zezithelo).

Ngemuva kokuqinisekiswa kwe-cytological ngo-1902 nguWalter Setton wezikhathi ezivamile zeMendelian, izimiso zokudlulisela nokuxhumana kwezinhlamvu zaqala ukuchazwa kusuka esikhundleni sokuziphatha kwe-chromosome kuseli.

Ngalo nyaka, ngo-1902, uCherakak Correns wachaza leli cala lapho, emva kokuwela izitshalo nge-corollas emhlophe nebomvu, inzalo yayinezimbali ezinemibala e-pink - ukubusa okungaphelele. Lokhu kubonakaliswa ezinhlobonhlobo (i-genotype Aa ) yalowo mkhuba, ophakathi nendawo ngokubhekelana ne-homozygous dominant ( AA ) nokuphindaphindiwe ( aa ) ama-phenotypes. Umphumela ofanayo uchazwa ezinhlobonhlobo eziningi zezitshalo zezimbali: i-pharynx yengonyama, i-hyacinth, ubuhle bebusuku, amajikijolobhisijoloji.

Ukubusa okungaphelele kungesizathu sokushintsha komsebenzi we-enzyme?

Indlela yokubukeka kwesimo esithathu sesici singachazwa ngombono womsebenzi we-enzyme, okuyinto ngokwemvelo kuyi-protein, futhi izakhi zofuzo ziqaphela isakhiwo seprotheyini. Esikhathini esitshalo esinama-homootygous dominotype ( AA ), ama-enzyme ayokwanela, kanti inani le-pigment lizohambisana nokujwayelekile ukuze kukhishwe umfutho weseli.

E-homozygotes ene-alleles esebenzayo (i- aa ) i-pigment synthesis iphukile, i-corolla ihlala ingagqotshiwe. Uma kwenzeka i-genotype ephakathi kwe-heterozygous ( Aa ), isakhi esiyinhloko sisekhona inani elithile le-enzyme elibhekele ukugqama, kepha akwanele umbala ogcwele ogcwele. Umbala uba "isigamu".

Izici ezizuzwa njengefa eliphakathi

Ifa elinjalo elingapheli lihlolwe kahle ngezibonakaliso ezinezibonakaliso eziguquguqukayo:

1. Ubuningi bombala. U. Batson, lapho ewela izinkukhu ezimnyama nezimhlophe zohlobo lwe-Andalusiya, wathola inzalo ngemifula yesiliva. Ekunqumeni umbala we-iris yesiso lomuntu, le ndlela nayo ikhona.
2. I-Degree yokuveza lo mkhuba. Isakhiwo soboya bomuntu sinqunywe yifa elingaphelele lesi sici. I-genotype AA inikeza izinwele ezinamabala, aa - imigqa eqondile, futhi abantu abanezinhlangothi ezimbili zombili banezinwele ezingenayo.
3. Izinkomba ezilinganiselwe. Ubude bendlebe kakolweni buzuzwa njengezimiso zokubusa okungaphelele.

Esizukulwaneni sesi-F2, inani lama-phenotypes lihambelana nenani lama-genotypes, elichaza ukubusa okungaphelele. Ukuhlaziya ukuwela ukuze kunqunywe ama-hybrid akudingekile, ngoba bahlukile ngaphandle komugqa ohlanzekile.

Ukukhahlela izici lapho uwela

Ukubusa okuphelele nokuphelele njengendlela yokusebenzisana kwezakhi zofuzo kwenzeka ngokuhambisana nesimiso semithetho kaG. Mendel. Esikhathini sokuqala, isilinganiso se-F2 sama-phenotypes (3: 1) asihambisani nesilinganiso sezinhlobo ze-genotypes (1: 2: 1), njengoba i-phenotypically inhlanganisela ye- AA ne- Aa alleles ibonakala efanayo. Khona-ke ukubusa okungaphelele kuwukuthi kwenzeke ngokuzenzakalelayo ku-F2 yenani lezinhlobo ezahlukene ze-genotypes ne-phenotypes (1: 2: 1).

Ngombala we-sitrobheli, ngonyaka ngifakwe ifa lomgomo wokubusa okungaphelele. Uma ukuwela isitshalo nge amajikijolo abomvu ( AA ) bese utshala ngamajikijolo amhlophe - i-genotype aa , khona-ke esizukulwaneni sokuqala zonke izitshalo ezitholakalayo zizonikeza izithelo ngombala obomvu ( Aa ).

Ukuwela ama-hybrids avela ku-F1, esizukulwaneni sesibili se-F2 sithola isilinganiso sezinzalo ezihambisana nalokho kwe-genotypes: 1AA + 2Aa + 1aa . Izitshalo ezingama-25% ezivela esizukulwaneni sesibili zizoletha izithelo ezibomvu nezingenagqatshiwe, 50% zezitshalo - pink.

Isithombe esifanayo sizobonwa ngezizukulwane ezimbili lapho uwela imigqa ehlanzekile yezimbali zobusuku bobusuku ngezimbali ezibomvu nezimhlophe.

Izici zefa uma kwenzeka ukubulawa kwamagciwane

Kwezinye izimo, isilinganiso se-phenotypes yenzalo kunzima ukuveza ukuthi izakhi zofuzo zithinta kanjani. Esizukulwaneni sesibili, ukwehlukana nokubusa okungaphelele kuhluke kokulindelekile: 2: 1, naku-3: 1 - ngokugcwele. Lokhu kwenzeka uma isimo esibucayi noma esicindezelayo sinikeza i-phenotype esimweni se-homozygous esingavumelani nokuphila (izakhi zofuzo ezibulalayo).

Ezimvu zaseKarakul ezinemibala ekhanda, amawundlu asanda kuzalwa ayenama-homozygous ngenxa ye-color allele efa ngenxa yokuthi i-genotype enjalo ibangela ukukhathazeka kokuthuthukiswa kwesisu.

Kubantu, isibonelo sokulimala kwesimo esiyinhloko segesi kuyinto brachidactyly (short-haired). Lesi sibonakaliso sibonakala esimweni se-genotype ye-heterozygous, kuyilapho ama-homozygote aphezulu efa ekuqaleni kwezinyathelo zokuthuthukiswa kwe-intrauterine.

I-Lethal ingabuye ibe yi-alleles esebenzayo yezakhi zofuzo. I-anemia ye-sickle-cell iholela, uma kwenzeka ukubukeka kwezinhlangothi ezimbili eziphindaphindiwe ku-genotype, ekushintsheni kokuma kwamaseli abomvu egazi. Amangqamuzana egazi awakwazi ukunamathela ngokuphumelelayo ne-oxygen, kanti izingane ezingu-95% ezine-anomaly ziyafa ngenxa yenkomo yokuphefumula kwe-oxygen. Ku-heterozygotes, uhlobo olushintshiwe lwe-erythrocyte aluthinti ngokulinganayo.

Ukukhahlela izibonakaliso phambi kwamagciwane abulalayo

Esizukulwaneni sokuqala, uma uwela i- AA x aa, ukubulawa akuveli, ngoba yonke inzalo izoba ne-genotype Aa. Nazi izibonelo zokuhlukaniswa kwesizukulwane sesibili ngamacala anezifo ezibulalayo:

Kubalulekile ukuqonda ukuthi kokubili izinsizakalo zisebenza ngaphansi kokubusa okungaphelele, futhi umphumela wokuvimbela okuyingxenye yalesi sici kuwumphumela wokusebenzisana kwemikhiqizo yegeni.