Ngā Tauira Pātai e Matapaki ana i te Ture a Mendel mō te Hurihanga Āhua
Pendahuluan
Ko ngā ture tuku iho ira a Mendel kua waiho hei tūāpapa mō ngā ira hou. Nā Gregor Mendel, he mōneka Czech, i whakatū ngā ture taketake e whakamārama ana i te tukunga iho o ngā āhuatanga mai i tētahi whakatipuranga ki tētahi whakatipuranga mā roto i ngā whakamātautau i ngā tipu pī. Heoi, i roto i te ao matatini o te koiora, he maha ngā wā ka puta ngā peka ke mai i ēnei ture taketake. Ko tētahi o aua āhuatanga ko te peka ke mai i ngā ture a Mendel.
Ka puta ngā rerekētanga āhua mai i ngā ture a Mendel ina kore ngā tauira tuku iho ira e rite ki ngā ture tawhito a Mendel. Ka puta pea ēnei rerekētanga i ngā āhuatanga maha, pērā i ngā taunekeneke ira, ngā whanaungatanga allelic uaua ake, me ētahi atu. Ka matapakihia e tēnei tuhinga ētahi tauira o ngā raruraru e pā ana ki ngā rerekētanga āhua mai i ngā ture a Mendel me pēhea te tātari i aua mea.
Tauira Pātai 1: Epistasis
Ko te Epistasis he āhuatanga e hunaia ana te pānga o tētahi ira e tētahi atu ira ehara i tōna ira. He maha ngā wā ka puta he momo āhua kāore e rite ki te ture wehewehe a Mendel. Anei ētahi tauira o ngā raruraru e pā ana ki te epistasis:
Pātai: I roto i ngā rōhi, ka whakatauhia te tae o te putiputi e ngā ira e rua. Mēnā he mahi a te ira A, ka puta he tae whero. Mēnā he mahi a te ira B, ka hiahiatia hei whakahohe i te ira A. Mēnā kāore he ira B, kāore rānei e mahi, e kore te ira A e whakaputa tae ahakoa kei reira. I roto i tētahi tipu me te ira AaBb, he aha te tūponotanga ka puta he tipu he putiputi whero?
Kōrero: I tēnei wā, he epistatic te ira B ki te ira A. Kia whero ai te putiputi, me kotahi te iti rawa o te ira mahi A me te ira mahi B kotahi. Me tātari tātou i ngā huinga ira pea ka tautoko i tēnei:
– Ka puta he momo whero i te ira AaBb, nā te mea he mahi tahi ngā ira A me B.
– Kāore e puta he putiputi whero i ētahi atu huinga pērā i te Aabb, te aaBb rānei, nā te mea me taunekeneke ngā ira e rua.
Ko te tūponotanga o tētahi tipu puawai whero he huinga o ngā ira A me B he mahi. Mēnā ka hangaia he ripanga ira mō AaBb x AaBb, ko te tūponotanga o tētahi tipu puawai whero (he ira matua i ngā ira e rua) he 9 i roto i te 16. Nō reira, ko te tūponotanga o te whiwhi putiputi whero he 9/16.
Tauira Pātai 2: Ārai Mate
Ko te ira whakamate he ira e pā kino ana ki te tangata e mau ana i taua ira, i te nuinga o te wā he ira homozygous. Ka taea e tēnei momo ira whakamate te pā ki te ōwehenga phenotypic e tumanakohia ana e ai ki ngā ture a Mendel.
Pātai: I roto i ngā kiore, ko te ira mō te huruhuru kōwhai (Y) te ira matua i te ira mō te huruhuru hina (y). Heoi, he whakamate te ira YY, ka mate wawe. Mena ka moea ngā kiore heterozygous e rua (Yy), he aha te ōwehenga o ngā momo āhua ora?
Kōrero: I roto i te whakawhiti Yy x Yy, ka matapaetia e te ture a Mendel tawhito he ōwehenga 3:1, engari i tēnei wā me whakaaro tātou ki te pānga whakamate:
– YY: Whakamate, e kore e whānau mai
– Āe: Kōwhai
– yy: hina
Ko ngā tāngata takitahi anake a Yy me yy ka ora:
– Ko te maha o ngā tāngata Yy (kōwhai) e rua hautoru o te katoa e ora ana (2 i roto i te 3).
– Ko te maha o ngā tāngata yy (hina) he kotahi hautoru o te katoa e ora ana (1 i roto i te 3).
Ko te ōwehenga āhuahanga o ngā kiore i ora ko 2:1.
Tauira Pātai 3: Hononga Ira
Kāore pea ngā ira e tata ana tetahi ki tetahi i runga i te ira kotahi e whai i te ture wehewehe motuhake a Mendel nā te mea he āhua tuku iho ngātahi ēnei; e mōhiotia ana tēnei ko te hononga.
Pātai: I roto i ngā namu hua, kei runga i te ira kotahi ngā ira mō te tae o te tinana (pango, parauri rānei) me te rahi o ngā parirau (noa, ngoikore rānei) ā, e hono ana. Hei tauira, e whakaatu ana te ira BbNn i te hononga i waenga i ngā ira B (pango) me N (noa) me b (parauri) me n (whakaroa). Mena ka whakawhitia ngā namu BbNn e rua, me pēhea te whakataurite i ngā momo āhua e puta mai ana mena he 20% te tere whakawhiti?
Kōrero: Ina honoa ngā ira i runga i te ira kotahi, ka whakarōpū ngā ira o ngā ira e tata ana tetahi ki tetahi i te wā e hangaia ana ngā gamete. Heoi, mā te whakakotahitanga, te whakawhiti rānei ka taea te wehewehe i a rātou.
– Nā te mea e 20% te tūponotanga o te whiti i te hononga, ka whai te toenga 80% i te tauira hononga paerewa.
– O te 80% e whai ana i te tauira hononga, mā te whakakotahi i ngā gamete ka nui ake ngā momo āhua, ko tēhea te mea e tata ana.
– Ko ngā hua o te whakawhiti ira (20%) ka puta he uri me ngā momo āhua hou.
Me wehewehe tātou i te huinga o ngā momo āhuahanga:
– He hononga nuinga (80%): Ngā momo āhua matua e ōrite ana ki ngā mātua (pango noa me te parauri pōturi).
– Me te whakakotahitanga (20%): Ka puta mai ngā momo hou o te pango puhoi me te parauri noa.
Hei whiwhi i te ōwehenga āhuatanga, ka mahia e mātou te tatau i runga i tēnei ōrau.
Whakamutunga
He mea nui kia māramahia ngā rerekētanga āhua mai i ngā ture a Mendel i roto i te horopaki o ngā ira matatini ake. Ko te epistasis, ngā ira whakamate, me te hononga ira he tauira noa iho o ngā āhuatanga e pā ana ki te tukunga iho o ngā āhuatanga, ā, he maha ngā wā ka puta he ōwehenga momo āhua e rerekē ana i ērā e tumanakohia ana i runga i ngā ture māmā a Mendel. Mā te mārama ki ēnei rerekētanga, ka taea e tātou te matapae tika ake me te mārama ki te tukunga iho ira i roto i ngā rauropi. He mea tino nui te ako i ēnei take ki te whakawhanake i te māramatanga hohonu ake ki ngā ira me te koiora whanaketanga.
