Law, kungakhathaliseki ifa. imithetho Mendel sika. zofuzo

Ngenxa yalokho, usosayensi ucwaningo K. Correns, G. de Vries, E. Cermak ngo-1900 base "balithola" imithetho zofuzo, zavela ngo-1865 umsunguli wesayensi ufuzo - Gregor Mendel. Ekuhloleni kwabo, usosayensi wasebenzisa indlela Hybridological lapho izimiso yefa zezici futhi izakhiwo ezithile eziphilayo abangu zavela. Kulesi sihloko sizohlola imithetho eyisisekelo ufuzo ukudluliswa, ukufunda zofuzo.

Mendel nocwaningo lwakhe

Isicelo indlela hybridological wamvumela ukusungula eziningi imithetho, bese lezi imithetho Mendel. Ngokwesibonelo, kwathiwa yisimiso ukufana we nzalo isizukulwane sokuqala (umthetho wokuqala Mendel). Wakhomba ukubonakaliswa Iqiniso F ₁ nzalo sici esisodwa kuphela, elawulwa yi-isakhi evelele. Ngakho, bewela izitshalo imbewu ipea izinhlobo okuyinto zingafani imbewu umbala (nephuzi), zonke nzalo isizukulwane sokuqala aphuzi kuphela imbewu umbala. Ngaphezu kwalokho, bonke laba bantu futhi kwakungamadodana genotype efanayo (babe heterozygotes).

umthetho wokuhlukaniswa

Ukuqhubeka isiphambano phakathi ndlovu othathwe nzalo-lokuqala isizukulwane, Mendel wathola F ₂ cleavage izici. Ngamanye amazwi, phenotypically ezikhonjwe izitshalo alleles esikhubazayo test sici (umbala oluhlaza imbewu) ku inani ingxenye eyodwa kwezintathu zonke nzalo. Ngakho, inkululeko lomthetho ifa avunyelwe Mendel kuyofikwa mshini ukudluliswa njengoba izakhi zofuzo evelele futhi esikhubazayo e ezizukulwane eziningana nzalo.

Ukunqamula likaNkulunkulu futhi poligibridnoe

Ekuhloleni okwalandela, Mendel nzima izimo ukuqaliswa yabo. Manje, ukunqamula izitshalo athathwa, njengoba ezimbili ezingefani, futhi inani elikhulu namabhuzu izinhlamvu okunye. izimiso Scientific balandela ifa ephezulu kanye esikhubazayo zezakhi zofuzo kanye cleavage Imiphumela etholwe, okungase emelelwa ifomula jikelele (3: 1) ^n, lapho n - isibalo namabhuzu izinhlamvu okunye okwehlukile abantu umzali. Ngakho, ngenxa kokuzalela ezimbili hybrid phenotypically yehlukanise nzalo isizukulwane sesibili kuyodingeka ifomu: (3: 1) ² = 9: 6: 1 noma 9: 3: 3: 1. Okusho ukuthi, esizukulwaneni nzalo yesibili kungabonakala nasemkhakheni izinhlobo ezine phenotypes: isitshalo ophuzi bushelelezi (9/16) zawo, ophuzi ukushwabana (3/16), oluhlaza bushelelezi (3/16) kanye ne oluhlaza imbewu esishwabene (ingxenye 1/16 ). Ngakho, umthetho, kungakhathaliseki ukuthi ifa wathola ubufakazi bakhe zezibalo, futhi poligibridnoe beyizalaniselana kwabonakala kancane monohybrid - "esikhulu" nomunye.

izinhlobo ifa

Zofuzo, ngamangqamuzana kukhona izinhlobo eziningana ukudluliswa izici futhi izakhiwo kusuka kubazali nezingane. Umbandela main nansi ukulawula ukuma sici kwenziwe noma nge isakhi esisodwa - ifa monogenic, noma ngaphezulu - ifa polygenic. Ngasekuqaleni sabuka umthetho, kungakhathaliseki ilifa zobuntu mono kanye ezimbili-hybrid kokuzalela, okungukuthi owokuqala, wesibili nowesithathu umthetho Mendel. Manje cabanga leli fomu njengoba ifa ezixhunyiwe. isisekelo sayo theory kuwumbono uThomas Morgan, okuthiwa i-chromosome. Ososayensi baye babonisa ukuthi, kanye nezimfanelo adluliselwa inzalo ngokuzimela, lukhona izinhlobo ifa lingenxa autosomal futhi adhesion ezihlobene ubulili.

Kulezi zimo, izimpawu ezimbalwa kwelinye ngabanye zizuzwe ndawonye njengoba ilawulwa izakhi zofuzo elise-chromosome efanayo wasibeka eceleni - nomunye. Bakha iqembu nokuxhumanisa ogama inombolo ilingana isethi haploid lezakhi zofuzo. Ngokwesibonelo, karyotype womuntu wama-chromosomes 46, okuhambelana amaqembu nokuxhumanisa 23. Kuye kwatholakala ukuthi ezincane ibanga phakathi izakhi zofuzo ku-chromosome, kancane kwenzeka phakathi inqubo crossover, okuholela lo mkhuba ukushintshashintsha zofuzo.

Njengoba kungenzeka izakhi zofuzo ngofuzo elise-X chromosome

Siyaqhubeka ukufunda amaphethini ifa, ukulalela imfundiso yokuziphendukela chromosomal uMorgan. izifundo bofuzo luye lwabonisa ukuthi kokubili abantu nezilwane (izinhlanzi, izinyoni, izilwane ezincelisayo) kukhona iqembu izimpawu ngalo mshini ifa ukuthi unomthelela phansi ngazinye. Ngokwesibonelo, umbala elingenamikhono amakati, imibala igazi ekunqandeni kubantu zilawulwa ufuzo ise ngokobulili X chromosome. Njengoba ukukhubazeka ohambelana sofuzo kubantu phenotypically ebonakaliswa eyizifo ngofuzo, isakhi sofuzo ngokuthi. Lezi zihlanganisa hemophilia nombala ngobumpumputhe. Kuvulwa Mendel noT Morgan avunyelwe ukusebenzisa imithetho zofuzo ezindaweni ezibucayi somphakathi wesintu njengoba imithi, ezolimo, ukufuya izilwane, izitshalo nezilwanyakazana ezincane.

Ubudlelwano obuphakathi izakhi zofuzo kanye nezici zabo kunqunywa

Nge nocwaningo lwanamuhla zofuzo, kwatholakala ukuthi imithetho esizimele ifa kukhona ekwandeni, kusukela ratio "1 isakhi sofuzo - 1 uphawu", engaphansi, akuyona jikelele. Ngo isayensi saba amacala eyaziwayo amaningi isakhi sofuzo isinyathelo futhi ekuhlanganyeleni nealellnyh Umumo wabo. zinhlobo ezinjalo zihlanganisa epistasis, complementarity, polymers. Ngakho, kwatholakala ukuthi inani melatonin isikhumba sombala obhekene umbala walo, ilawulwa iqembu izici sitholwa njengefa. I genotype evelele ngaphezulu sofuzo kubantu obangela ukwakheka kombala, lo mnyama isikhumba. Lesi sibonelo sibonisa yokusabela ezifana polymers. Ngo izitshalo, lolu hlobo ifa esingokwemvelo wokudla zama-umndeni lapho okusanhlamvu umbala polymeric elawulwa iqembu lokhu ngezakhi ezingamaqoqo.

Ngakho, genotype zisifake ngamunye uqukethe oluphelele. Yasungulwa ngenxa ekuthuthukiseni zomlando kwezinhlobo - phylogeny. Isimo izimpawu kakhulu kanye nezici ezikhethekile - kuwumphumela we isakhi sofuzo ekuhlanganyeleni, kokubili allelic futhi okungezona allelic, futhi kungaba nomthelela ekuthuthukiseni izici eziningana umzimba.