I-polymorphism - iyini? I-polymorphism ye-genetic

I-polymorphism ye-genetic yisimo lapho kutholakala khona izinhlobo ezihlukahlukene zegciwane, kodwa ukuvama kwesakhi sofuzo esingavamile kakhulu kunabantu abangaphezu kweyodwa. Ukugcinwa kwayo kungenxa yokushintshashintsha kwezakhi zofuzo, kanye nokuphindaphinda kwabo njalo. Ngokusho kocwaningo olwenziwe ososayensi, i-polymorphism yezakhi zofuzo iye yasakazeka, ngoba ukuhlanganiswa kwezakhi zofuzo kungaba izigidi eziningana.

Isakhiwo esikhulu

Kusukela emkhawulweni omkhulu we-polymorphism, ukulungiswa okuhle kwesibantu kuya endaweni entsha kuncike, futhi kulokhu kwenzeka ukuziphendukela kwemvelo kwenzeka ngokushesha. Linganisa inani eliphelele lama-polymorphic alleles, usebenzisa izindlela zendabuko zendabuko, akunakwenzeka. Lokhu kubangelwa ukuthi ukutholakala kwesakhi sofuzo esivela ku-genotype kungenxa yokuwela kwabantu abanezici ezahlukene ze-phenotypic ezithathwe yi-genome. Uma wazi ukuthi iyiphi ingxenye yendawo ethile eyenziwe ngabantu abanezinhlobo ezahlukene ze-phenotypes, khona-ke kungenzeka ukuthi kusungulwe inombolo ye-alleles lapho ukubunjwa kwesici esithile kuncike khona.

Konke kwaqala kanjani?

I-Genetics yaqala ukukhula ngokushesha kuma-60s ekhulwini lokugcina, lapho i- electrophoresis yamaprotheni noma ama-enzyme ku-gel yaqala ukusetshenziswa, okwenza kube lula ukuthola uhlobo lwe-genetic polymorphism. Iyini le ndlela? Kungenxa yakhe ukuthi ukunyakaza kwamaprotheni ensimini kagesi kubangelwa, okuxhomeke kubukhulu besiprotheni esithwala, ukulungiswa kwayo, kanye nokukhokhiswa kwenani lezingxenye ezahlukene zejel. Ngemuva kwalokhu, kuye ngokuthi indawo nenani lamabala avela, ukuhlonza kwemithi enqunyiwe kwenziwa. Ukuhlola amaprotheni polymorphism emphakathini, kufanelekile ukuhlola cishe okungu-20 noma ngaphezulu loci. Khona-ke, usebenzisa indlela yezibalo, inani lezinhlobo ze- allelic lizimisele , kanye nesilinganiso se-homo-and heterozygotes. Ngokwezicwaningo, ezinye izakhi zofuzo zingaba yi-monomorphic, kanti ezinye - zi-polymorphic ezingavamile.

Izinhlobo ze-polymorphism

Umqondo we-polymorphism ububanzi obukhulu kakhulu, kufaka phakathi inguqulo yesikhashana futhi elinganisiwe. Kuxhomeke ekubalukeni okukhethiwe kwegesi kanye nokukhethwa kwemvelo, okucindezela abantu. Ngaphezu kwalokho, ingaba yi-genomic ne-chromosomal.

I-polomorphism ye-Genomic ne-chromosomal

I-polymorphism yegeneshi iboniswa emzimbeni yi-alleles esilinganisweni esingaphezu kwesinye, isibonelo esicacile salokhu kungaba igazi. I-Chromosomal yimpikiswano ngaphakathi kwama-chromosomes, okwenzeka ngenxa yokuphelelwa isikhathi. Kukhona umehluko kwizigaba ze-heterochromatic. Uma kungekho ukukhubazeka okuholela ekuphazanyeni noma ekufeni, izinguquko ezinjalo azithathi hlangothi.

I-polymorphism yesikhashana

I-polymorphism esheshayo yenzeka lapho inani labantu lishintsha i-allele eyayivame ukujwayela, enye ehlinzeka ngenethiwekhi yayo ngokuvumelana nezimo eziningi (lokhu kuthiwa yi- allelicism eminingi). Ngalokhu okuhlukahlukene kukhona ukuguqulwa okuqondisiwe kumaphesenti we-genotypes, ngenxa yalokho, ukuguquka kwemvelo kwenzeka, futhi ukuguqulwa kwayo kugcwaliseka. Isimo sezindlela zezimboni singaba isibonelo esihle, esichaza i-polymorphism yesikhashana. Okuyikho, kubonisa i-butterfly elula, okuyinto, ngokuthuthukiswa kwemboni, ishintshe umbala omhlophe wamaphiko ayo kuya emnyama. Lesi senzakalo saqala ukubonwa eNgilandi, lapho kunezinhlobo ezingaphezu kuka-80 zezimvemvane ezenziwe ngezimbali ezinemibala eluhlaza okwesibhakabhaka zaba mnyama, okwakubonakala kuqala ngemva kuka-1848 eManchester ngenxa yokuthuthukiswa okusheshayo kwembonini. Kakade ngo-1895 amabhuzu angaphezu kwama-95% athole umbala omnyama wamaphiko. Izinguquko ezinjalo zihlotshaniswa nokuthi izihlahla zomuthi ziye zaba yi-sooty engaphezulu, futhi izimvemvane ezilula ziba yisisulu esilula sabaningikazi nabanama-ruffian. Izinguquko zenzeke ngenxa ye-alleant melanistic alleles.

I-polymorphism elinganiselayo

Incazelo ye "polymorphism elinganiselayo" ichaza ukungabi khona kweshintsho kunoma yibuphi ubudlelwane obuningi bezinhlobo ezahlukene ze-genotypes emphakathini osendaweni enempilo yokuhlala. Lokhu kusho ukuthi, kusukela esizukulwaneni kuya kwesinye isizukulwane, isilinganiso sihlala sinye, kepha singashintsha ngokungenasici ngaphakathi kwesinye noma esinye isamba esihlala njalo. Uma kuqhathaniswa ne-polymorphism engapheli, elinganiselayo - kuyini? Okokuqala, kuyisimo esithile senqubo yokuziphendukela kwemvelo. II Shmalhausen ngo-1940 naye wamnika igama lokulinganisa i-heteromorphism.

Isibonelo se-polymorphism elinganiselayo

Isibonelo esicacile se-polymorphism elinganiselayo kungaba khona kwamadoda amabili ocansini ezilwaneni eziningi ezingapheli. Lokhu kubangelwa ukuthi banezinzuzo ezilinganayo ezikhethiwe. Isilinganiso sabo ngaphakathi kwesibalo esifanayo ngaso sonke isikhathi siyafana. Ngaphambi kwesithembu kubantu, isilinganiso sokukhetha sabamele bobulili bobabili singaphulwa, lapho kwenzeka abameleli bobulili obufanayo bangabhujiswa ngokuphelele noma baqedwe ekuzalweni ngokukhulu kunabameleli bobulili obuhlukile.

Esinye isibonelo ubulungu beqembu legazi kuhlelo lwe-ABO. Kulesi simo, imvamisa yezinhlobo ezahlukene ze-genotypes ezihlukene ezihlukene zingase zihluke, kepha ngokuhambisana nalokhu kusukela esizukulwaneni kuya esizukulwaneni asishintshi ukuhlala kwayo. Kalula nje, ayikho i-genotype enenzuzo yokukhetha ngaphezu komunye. Ngokwezibalo, amadoda aphethe iqembu legazi lokuqala anesikhathi eside sokulindela ukuphila kunabo bonke ubulili obuqinile namanye amaqembu egazi. Ngokubambisana nalokhu, ingozi yokuhlalisa isilonda esidalwa yi-duodenal phambi kweqembu lokuqala iphakeme, kodwa ingahle iguqulwe, futhi lokhu kuzobangela ukufa uma kunakekelwa okwesikhashana.

Ibhalansi ye-Genetic

Lesi simo esibucayi singahlukunyezwa emphakathini ngenxa yokuguquka kokuzenzekelayo, kepha kufanele kube nemvamisa ethile nasesizukulwaneni ngasinye. Ucwaningo luye lwabonisa ukuthi i-polymorphisms yezinhlobo zomzimba we-hemostasis uhlelo, okuchazwa ngalo ukuthi kucacisa ukuthi inqubo yokuziphendukela kwemvelo inikela kulezi zinguquko noma, ngokuphambene, ukuphikisana, kubaluleke kakhulu. Uma sibheka inkambo yenqubo eguquguqukayo kunabantu abathile, singakwazi futhi ukwahlulela ukubaluleka kwayo kokuzivumelanisa. Kungalingana nomunye uma ukuguqulwa kungavunyelwe ngesikhathi senqubo yokukhetha, futhi azikho izithiyo zokusabalalisa.

Amacala amaningi abonisa ukuthi inani lalezi zakhi zofuzo lingaphansi kweyodwa, futhi uma kwenzeka ukungakwazi ukukhiqiza okunjalo, konke kuncipha kuya ku-0. Izinguquko zalolu hlobo zilahlwa ngenkathi kukhethwa kwemvelo, kodwa lokhu akukhiyi izinguquko eziphindaphindiwe kulesisindo esifanayo, esikhombisa ukuqedwa , Okuyinto eyenziwa ngokukhethwa. Khona-ke ukulingana kutholakala, izakhi zofuzo eziguqulwa zingabonakala noma, ngokuphambene, zinyamalale. Lokhu kuholela enkambisweni elinganiselayo.

Isibonelo esingachaza ngokucacile lokho okwenzekayo yi-anemia yegilane-cell. Kulesi simo, i-gene eguquguqukayo eguquguqukayo embusweni we-homozygous inomthelela ekufeni komzimba. Izinto eziphilayo ze-heterozygous ziphila, kepha ziyakwazi ukubhekana ne-malaria. I-polymorphism elinganiselayo yegciwane le- sickle-cell anemia geni ingalandelwa ezindaweni zale sifo esishisayo. Kuzo-homozygotes ezinabantu abaningi (abantu abanezinhlobo ezifanayo) ziqedwa, kanye nalokhu kukhethwa kusebenza nge-heterozygotes (abantu abanezinhlobo ezahlukene zegciwane). Ngenxa yokukhethwa kwe-multi-vector okuqhubekayo ku-gene pool yabantu, ama-genotypes agcinwa esizukulwaneni ngasinye, esiqinisekisa ukuthi isimo sendawo siyakwazi ukuzivumelanisa kangako. Kanye nokutholakala kofuzo lwe-sickle-cell anemia emphakathini wabantu, kunezinye izinhlobo zezakhi zofuzo ezibonisa ukuchithwa kwe-polymorphism. Lokhu kunikeza? Impendulo yalo mbuzo iyoba yinto efana ne-heterosis.

Izinguquko ze-Heterozygous ne-polymorphism

I-polymorphism ye-Heterozygous inikeza ukungabi khona kwezinguquko ze-phenotypic phambi kokuguqulwa okuguquguqukayo, ngisho noma kuyingozi. Kodwa ngokuhambisana nalokhu, bangakwazi ukubuthelela emphakathini ezingeni eliphakeme, elingadlula ukuguqulwa okunamandla okulimazayo.

Isimo esibalulekile senqubo yokuziphendukela kwemvelo

Inqubo yokuziphendukela kwemvelo iyaqhubeka, futhi isimo sayo sokubophezela yi-polymorphism. Lokho lokhu - kubonisa ukuvumelanisa njalo kwendawo ethile endaweni yayo. Izinto eziphilayo ze-heterozygous ezihlala ngaphakathi kweqembu elifanayo zingaba i-heterozygous futhi zidluliselwa ezizukulwaneni ngezizukulwane iminyaka eminingi. Ngokuhambisana nalesi sibonakaliso se-phenotypic, kungenzeka ukuthi - ngenxa yesitoreji esikhulu sokuhlukahluka kofuzo.

Isakhi se-fibrinogen

Ezimweni eziningi, abacwaningi bacabanga ukuthi i-polymorphism yegenesisini ye-fibrinogen iyisandulela ekuthuthukisweni kwesifo so-ischemic. Kodwa okwamanje, inkinga ihamba phambili, lapho izici zofuzo nezitholakalayo zikwazi ukufaka ithonya labo ekuthuthukiseni lesi sifo. Lolu hlobo lwe-stroke luqala ngenxa ye-thrombosis yamathambo e-cerebral, futhi, ngokutadisha i-polymorphism yegenesisini ye-fibrinogen, izinqubo eziningi zingaqondwa, zithonya ukuthi yiluphi uhlobo lokugula okungavinjelwa. Ukuxhumana kwezitshengiselo zezofuzo kanye nezinkomba zegazi ezinomzimba okwamanje kufundiswa ososayensi ngokungapheli. Ucwaningo oluthe xaxa luzovumela ukuthonya inkambo yesifo, ukuguqula inkambo yayo noma ukulivimba nje ekuqaleni kwesigaba sokuthuthukiswa.