Morgan chromosomal theory: definition, amalungiselelo eziyisisekelo kanye nezici

Kungani izingane sifuze ababelethi babo? Kungani eminye imikhaya izifo ezithile ezifana umbala ubumpumputhe, polydactyly, hypermobility ngokuhlanganyela, cystic fibrosis? Kungani kufanele eziningi izifo ezithinta kuphela abesifazane nabanye - amadoda kuphela? Namuhla sonke siyazi ukuthi izimpendulo zale mibuzo kumele ifuneka ufuzo, ie-chromosomes ukuthi ingane ithola kumzali ngamunye. Futhi lolu lwazi, isayensi yesimanje ubophekile ukuba Thomas Hunt Morgan - zofuzo American. Wachaza inqubo ngokudlulisela ukwaziswa kwezakhi zofuzo futhi uye waklama ndawonye nozakwethu chromosomal imfundiso yokuziphendukela ifa (owayevame ukubizwa ngokuthi chromosome imfundiso yokuziphendukela Morgan), egcwele legumbi isayensi yezakhi zofuzo yanamuhla.

Umlando yokutholakala

Kungaba iphutha ukusho kanjalo Thomas Morgan waba ngowokuqala babe nesithakazelo kuyi-ukudluliselwa ukwaziswa kwezakhi zofuzo. Abacwaningi lokuqala abaye bazama ukuqonda indima wama-chromosomes e-ifa kungenziwa ziyimisebenzi Chistyakov, Beneden, Rabl ku 70-80-yalolucwaningo kwekhulu XIX.

Zazingekho ezinamandla ukuze bakwazi ukubona isakhiwo chromosome. Futhi elithi "chromosome" Khona-ke, futhi, akazange. It yethulwa i-German usosayensi Heinrich Valdeyr ngo-1888.

Isazi sezinto eziphila kuleli German Theodor Boveri ngenxa ucwaningo yakhe yafakazela ukuthi kubalulekile ukuba ukuthuthukiswa evamile yezindlela umzimba evamile isibalo saso zama-chromosomes e, futhi ngokweqile zabo noma ukushoda kuholela kombungu ezinzima. Ngokuhamba kwesikhathi, umbono wakhe waba lolungenamaphutsa baqinisekisa. Singasho ukuthi imfundiso chromosome T. Morgan ithole elikhuluphalisiwe yokuqalisa ukubonga lokucwaninga Boveri.

Qala zocwaningo

Synthesis ekhona ulwazi ngemfundiso yokuziphendukela ufuzo, ukwelekelela nokuthuthukisa bakwazi ukufinyelela Thomas Morgan. Njengoba into ucwaningo lakhe wakhetha izithelo fly, hhayi ngephutha. Kwakuwusuku into ephelele izifundo yokudlulisela ulwazi zofuzo - chromosome amane kuphela, wenzalo sikhashana esifushane. Morgan waqala ukwenza ucwaningo, usebenzisa Imigqa ehlanzekile Izinambuzane. Ngokushesha wathola ukuthi igciwane amaseli isethi eyodwa wama-chromosomes, okungukuthi 2 esikhundleni 4. Morgan evezwe indlela owesifazane ocansini chromosome X, iduna - njengoba Y.

ifa Sex-exhumene

Morgan chromosome theory selukhombisile ukuthi kukhona izimpawu esiqondile ubulili-ezixhunyiwe. Fly, ngawo usosayensi kwenziwe ucwaningo lakhe, okuyinto evamile has a-red-eye, kodwa ngenxa yokwanda koshintsho ka yilesi sakhi sabantu kwakukhona abase ezimhlophe sivule amehlo, futhi phakathi kwabo babebaningi besilisa ngaphezulu. Isakhi, okuyinto unomthwalo umbala iso impukane itholakala-X chromosome, ku-Y-chromosome akuyona. Okusho ukuthi, abesifazane ukweqa, omunye X chromosome esesikhundleni isakhi soguquko lwegciwane singalawuleka, kanye ferruginous okungenzeka abesilisa khona isici e nenzalo sizoxhunywa phansi. Indlela elula ukubonisa lo emudwebeni:

• P: XX 'x X'Y;
• F _1: XX, XY, X'X 'X'Y.

X - zesifazane ubulili chromosome noma isakhi sofuzo ngaphandle iso owesilisa omhlophe; X 'chromosome isakhi sofuzo abamhlophe samehlo.

Wokufunda Ukunqamula imiphumela:

• XX '- abomvu uneso zesifazane isakhi sofuzo yenethiwekhi esidlule iso. Ngenxa yokuba khona yesibili X-chromosome isakhi sofuzo soguquko lwegciwane singalawuleka "udlulela" enempilo, futhi kubonisa ukuthi akukho sici phenotype.
• X'Y - owesilisa omhlophe uneso owayethatha kusukela X kamama chromosome nge isakhi sofuzo asabekayo. Ngokuloba eyodwa kuphela ye-X-chromosome imfanelo asabekayo lutho ukuvimba, kanye buvela phenotype.
• X'X '- omhlophe uneso chromosome zesifazane ngofuzo isakhi sofuzo soguquko lwegciwane singalawuleka kusukela umama nobaba. Insikazi kuphela uma kokubili X-chromosomes e athwale abamhlophe isakhi sofuzo samehlo, sizovela ku phenotype.

Imfundiso chromosomal ufuzo Thomas Morgan wachaza lo mshini ifa izifo eziningi zofuzo. Ngenxa izakhi zofuzo X chromosome okuningi kuka ku Y-chromosome, kuyaqondakala ukuthi unesibopho izimpawu kakhulu umzimba. I-X chromosome elivela kumama ngocansi njengamadodana kanye namadodakazi, kuhlanganise izakhi zofuzo ezibangela property umzimba, izimpawu zangaphandle lesi sifo. Kanye-X-exhumene kukhona ifa Y-ezixhunyiwe. Kodwa-Y-chromosome kuphela amadoda, ngoba uma kwenzeka noma yimuphi kuguquka, ke ingadlulela kuphela titukulwane letidvuna.

Imfundiso chromosomal ufuzo Morgan sasizwa ukuba siwaqonde amaphethini yokudlulisela izifo ezihlukahlukene zofuzo, Nokho, ubunzima ezihambisana nemithi yazo, akuvumelekile kuze kube manje.

crossover

Phakathi nesifundo, umfundi uTomase Morgan Alfred Sturtevant wathola lo mkhuba Ukunqamula ephezulu. Njengoba ucwaningo okwalandela, inhlanganisela ezintsha zofuzo zenzeka ngenxa kokuwelela. Nguye kwephula inqubo exhumene ifa.

Ngakho-chromosome theory T. Morgan wathola esinye isikhundla esibalulekile - phakathi Ama-chromosomes e homologous kwenzeka Ukunqamula-phezu, futhi imvamisa yayo kunqunywa ibanga phakathi izakhi zofuzo.

eziyisisekelo

Nokumisa imiphumela ucwaningo kwenziwe usosayensi, Uyoletha isikhundla eyisisekelo inkolelo-mbono yokuziphendukela chromosomal uMorgan:

1. Izimpawu zincike izakhi zofuzo umzimba komculo kuma-chromosome.
2. Amangqamuzana elilodwa chromosome zize zidlulele enzalweni bamba. Amandla adhesion mkhulu, ezincane ibanga phakathi izakhi zofuzo.
3. I-chromosomes homologous waphawula mkhuba Ukunqamula ephezulu.
4. Ukwazi ukuvama kokuwelela chromosome ezithile, singakwazi ukubala ibanga phakathi izakhi zofuzo.

Isikhundla inkolelo-mbono yokuziphendukela chromosomal uMorgan futhi Morgan yesibili ngokuthi umthetho.

ukuqashelwa

Imiphumela yocwaningo ababebheka lolungenamaphutsa. Morgan chromosome theory kuye kwasusa umgoqo e biology of the kwekhulu lamashumi amabili. Ngo-1933, i-kokutholakala indima lezakhi zofuzo ufuzo uMklomelo KaNobel waklonyeliswa usosayensi.

Eminyakeni embalwa kamuva, Thomas Morgan wathola Copley Medal ophumelele ngamalengiso emkhakheni wokusebenza kwezakhi zofuzo.

Manje Morgan chromosome imfundiso yokuziphendukela ufuzo sifundwa kuwo izikole. Yena enikelwe izihloko nezincwadi eziningi.

Izibonelo waxhumana ifa phansi

Morgan chromosome theory luveza ukuthi izakhiwo umzimba abizwa kunqunywa yizakhi zofuzo babeka phansi kwalo. Imiphumela eziyinhloko ithole Thomas Morgan, wanikeza impendulo yombuzo ukudluliselwa kwezifo ezifana hemophilia, Lowe syndrome, ubumpumputhe, Bruttona isifo.

Kwatholakala ukuthi izakhi zofuzo zonke lezi zifo zitholakala-X chromosome nabesifazane, lezi zifo anizikhokheli njalo, njengoba le-chromosome enempilo ingaziguqula chromosome nge isakhi sofuzo isifo. Abesifazane abangekho aqaphele, kungaba abathwali izifo zofuzo, abese ebonakaliswa izingane.

In amadoda, X-exhumene isifo, noma izimpawu phenotypic avele, ngoba akukho-X chromosome enempilo.

Imfundiso chromosomal ufuzo T. Morgan isicelo ukuhlaziya yomlando womkhaya ukuze bathole izifo zofuzo.