Imibuzo Eyisibonelo Ngokuxoxa Ngezinto Eziphathelene Nofuzo
Izakhi zofuzo ziyigatsha lebhayoloji elifunda izakhi zofuzo, ifa lezici, kanye nendlela lolu lwazi lwezakhi zofuzo oluvezwa ngayo ngesimo sezinto eziphilayo. Ukuqonda izakhi zofuzo kubalulekile ngoba kuchaza indlela izinto eziphilayo ezikhula ngayo, ezisebenza ngayo, ezizalana ngayo, futhi ezisabela ngayo endaweni ezizungezile. Ukuze kujuliswe lokhu kuqonda, lesi sihloko sizokwethula imibuzo eminingana eyisibonelo kanye nezingxoxo zayo ezihlobene nezakhi zofuzo.
Umbuzo 1: Ifa Lezimpawu kuMendel
Umbuzo: Uma isitshalo se-pea esibizwa ngokuthi i-heterozygous for tall (Tt) sihlanganiswa nesitshalo se-pea esifushane (tt), yiliphi iphesenti lenzalo elizoba lide?
Ingxoxo:
Ake siqale ngokuqonda izinhlobo ze-genotype ezinikeziwe. I-`T` iyi-allele eyinhloko yokuphakama, kanti i-`t` iyi-allele ephindaphindayo echaza ukufushane. Isitshalo eside esine-heterozygous sine-genotype ethi `Tt`, kanti isitshalo esifushane sine-genotype ethi `tt`.
Uma sakha isikwele sikaPunnett salesi siphambano, singabala izinhlobo zofuzo ezingaba khona zenzalo:
``
T t
------
t | Tt tt
t | Tt tt
``
Kusukela kuthebula elingenhla:
– Ama-50% enzalo (`Tt`) anohlobo olude lwezakhi zofuzo ngoba kukhona i-allele eyodwa evelele ethi `T`.
– Ama-50% enzalo (`tt`) ane-genotype emfushane.
Ngakho-ke, ama-50% enzalo azoba made.
Umbuzo 2: Ukuhlaziywa Kokuxhumana Kwezakhi Zofuzo
Umbuzo: Izakhi zofuzo A no-B zitholakala kumayunithi emephu angu-20 e-chromosome efanayo. Uma umuntu one-genotype ye-AB/ab edlula ku-gametogenesis, yiliphi iphesenti lama-gametes azophinde ahlangane?
Ingxoxo:
Ukuvama kokuhlangana kabusha phakathi kwezakhi zofuzo ezimbili ezitholakala ku-chromosome efanayo kungabalwa ngokusekelwe ebangeni lazo lezakhi zofuzo. Ngokuphathelene namayunithi emephu, ibanga leyunithi eyodwa yemephu cishe lilingana nethuba elingu-1% lokuhlangana kabusha. Ngakho-ke, ngebanga lamayunithi emephu angu-20, kunethuba elingu-20% lokuthi ukuhlangana kabusha phakathi kwezakhi zofuzo u-A no-B kuzokwenzeka.
Lokhu kusho ukuthi ekwakhekeni kwama-gametes avela kubantu be-AB/ab:
– Ama-gametes angu-20% azoba yi-recombinant, okungukuthi `Ab` noma `aB`.
– Ama-gametes angu-80% azobe engahlanganisi kabusha, okungukuthi `AB` noma `ab`.
Umbuzo 3: Ifa Elilinganiselwe
Umbuzo: Uma ukuphakama kwesitshalo kuthonywa izakhi zofuzo ezimbili (i-Aa ne-Bb) ngemiphumela eyengeziwe, futhi i-allele ngayinye eyinhloko inezela u-5 cm ekuphakameni kwesisekelo okungu-50 cm, bala ukuphakama kwesitshalo esine-genotype AABb.
Ingxoxo:
Izakhi zofuzo A no-B zinegalelo elingeziwe ekuphakameni kwesitshalo. Kuhlobo lwezakhi zofuzo lwe-AABb:
– Kunezinhlobo ezimbili ezivelele ze-'A': ezimbili ze-'A' zinikeza u-2×5 cm owengeziwe = 10 cm.
– I-allele eyinhloko ethi `B` inye: eyodwa ethi `B` inikeza i-1×5 cm eyengeziwe = 5 cm.
Ukuphakama kwesisekelo sesitshalo kungama-50 cm. Ngokungezwa komphumela we-allele evelele, ukuphakama okuphelele kwesitshalo kuba:
50 cm (ukuphakama kwesisekelo) + 10 cm (kusukela ku-`AA`) + 5 cm (kusukela ku-`B`) = 65 cm.
Ngakho-ke, isitshalo esine-genotype ye-AABb sizoba ngamasentimitha angu-65 ubude.
Umbuzo 4: Izifo Zofuzo kanye Nokungenzeka Kwazo
Umbuzo: Emndenini, ubaba ungumthwali wesici esiphindaphindayo se-albinism (Aa) kanti umama akanayo i-allele ephindaphindayo (AA). Angakanani amathuba okuba izingane zakhe zibe yi-albino?
Ingxoxo:
Ubu-albinism buyisimo sokuphindaphindeka, okusho ukuthi kudingeka ama-allele amabili aphindaphindeka (aa) ukuze kuvele lesi sici. Uhlobo lwe-genotype lukababa luyi-'Aa' kanti olukamama luyi-'AA'.
Cabanga ngezinhlanganisela ezingaba khona esikweleni sePunnett:
``
A A
------
A | AA AA
a | Aa Aa
``
Imiphumela ehlanganisiwe ikhombisa:
– Ama-50% ezingane azoba nohlobo lwe-'AA' (olungathwali, olungewona ama-albino).
– 50% wezingane zizoba nohlobo lwe-genotype oluthi `Aa` (oluthwalayo, olungewona ama-albino).
Akukho ithuba lokuthi izingane zabo zizoba nohlobo lwe-'aa', ngakho-ke amathuba okuba nomntwana oyi-albino angama-0%.
Umbuzo 5: Ukuhlaziywa kwe-Chromosome exhumene nobulili
Umbuzo: Owesifazane ongaboni kahle emehlweni (X^BX^b) ushada nendoda evamile (X^BY). Angakanani amathuba okuba babe nendodana engaboni kahle emehlweni?
Ingxoxo:
Ukungaboni imibala kuhlotshaniswa ne-chromosome X futhi ku-recessive (X^b). Abesifazane bangabathwali futhi bane-genotype X^BX^b kanti abesilisa abavamile bane-X^BY. Ukusebenzisa isiphambano:
``
X^BY
------
X^B | X^BX^BX^BY
X^b | X^BX^b X^bY
``
Imiphumela yokuzalanisa abafana:
– Abafana abangu-50% bazoba nohlobo lwe-genotype X^BY (olujwayelekile).
– Abafana abangu-50% bazoba nohlobo lwe-genotype X^bY (ubumpumputhe bombala).
Ngakho-ke, kunethuba elingu-50% lokuthi indodana yabo izobe ingenawo umbala.
Engxoxweni engenhla, sihlole izimo eziningana ezibonisa izimiso eziyisisekelo zezakhi zofuzo, kusukela kwezakudala kuya kwezanamuhla. Lokhu kuqonda akusizi nje kuphela ezivivinyweni kodwa futhi kusebenza njengesisekelo socwaningo nentuthuko ezifundweni ze-biotechnology kanye nokuthuthukiswa kokwelashwa kwezakhi zofuzo. Ngokuthuthukisa amakhono ethu okuhlaziya ezimweni ezahlukene, ukuqonda kwethu ukuthi impilo isebenza kanjani kuyajula.
