Ngā Ture Whakatakotoranga Pūtake: Te Pūtake o te Hanganga DNA
Ko te DNA (waikawa deoxyribonucleic) te rauemi ira e penapena ana i ngā mōhiohio e tika ana mō te whanaketanga, te mahi, te tipu, me te whakaputa uri o ngā mea ora katoa e mōhiotia ana. Ko tētahi o ngā huānga matua e āhei ai te DNA ki te mahi pai ko ngā ture takirua turanga. Ka ruku hohonu ake tēnei tuhinga ki ngā ture takirua turanga, me pēhea te kitenga, he aha te hiranga, me pēhea te whakamahi i roto i te koiora ngota.
Te Māramatanga Taketake me te Hītori
He aha te Hononga Pūtake?
Ko te tikanga, e rua ngā miro roa o te DNA e hanga ana i tētahi hanganga porowhita takirua. Ko tēnei hanganga, e rite ana ki tētahi arawhata piko, he "ngā karu" i hangaia mai i ngā turanga nucleotide takirua. E whā ngā momo nucleotide i roto i te DNA: adenine (A), thymine (T), guanine (G), me te cytosine (C). Ko te ture takirua turanga he mātāpono e kī ana:
– Ka honoa tonutia te Adenine (A) me te Thymine (T)
– Ka hono tonu te Guanine (G) ki te Cytosine (C)
Ko ēnei ture takirua he hua nō te hanganga ngota ngota o ia turanga me te hononga hauwai e āhei ai te pumau mōrahi mō te porowhita takirua.
Hītori o te Kitenga
I te tau 1953, i kitea tuatahitia ngā ture mō te takirua turanga e James Watson rāua ko Francis Crick i te wā i whakaarohia ai e rāua he tauira takirua-porowhita mō te hanganga DNA. I whakawhirinaki tēnei kitenga ki ngā raraunga whakamātautau mai i a Rosalind Franklin rāua ko Maurice Wilkins, nā rāua i whakamahi te diffraction hihi-X hei tohu i te hanganga porowhita o te DNA. Nā roto i tā rāua tauira auaha, i kitea e Watson rāua ko Crick ko te pumau o te hanganga o te DNA ka tutuki mā tēnei takirua turanga motuhake.
Tikanga Hononga Pūtake
Hanganga Matū o ngā Pūtake
Mā ngā rerekētanga matū me ngā rerekētanga āhuahanga i waenga i ngā pūtake ka taea te hono motuhake. E rua ngā here hauwai ka hangaia e te adenine me te thymine, e toru ia ngā here hauwai ka hangaia e te guanine me te cytosine. He mea nui ēnei here hauwai nā te mea, ahakoa he ngoikore takitahi, ina nui te maha, ka whakaratohia he pumau hei pupuri i te pumau ira o te DNA.
Te Mātāpono o Chargaff mō te Ōritetanga
I mua i te kitenga a Watson rāua ko Crick, i kitea e tētahi kaipūtaiao ko Erwin Chargaff te mātāpono ōrite, e kī ana ko te maha o ngā pūtake purine (A me G) he rite tonu ki te maha o ngā pūtake pyrimidine (T me C) i roto i tētahi tauira DNA. Ko te tikanga o tēnei ko te maha o ngā pūtake A he rite ki te maha o ngā pūtake T, ā, ko te maha o ngā pūtake G he rite ki te maha o ngā pūtake C, he pūtake pakari tēnei mō ngā ture takirua i whakatakotoria e Watson rāua ko Crick.
Te Hiranga o te Koiora
Te Pūmautanga Ira
Mā ngā ture o te takirua pūtake ka noho pumau, ka tika hoki ngā mōhiohio ira ina tāruatia, ina whakarerekētia rānei te DNA. Ina wehea ngā pūtau, me whiwhi ia pūtau tamahine i tētahi tārua tika o te DNA o tōna matua. Ko te hanganga takirua pūtake i te wā o te tāruatanga he rite ki tētahi mahere, e āhei ai ngā whākōkī ki te mahi pai.
Te Whakapuakitanga Ira
He mahi nui anō hoki tā te hononga turanga i roto i te whakawhiti me te whakamāori, arā, ngā tukanga e whakamahia ai te DNA hei hanga RNA, kātahi ka whakamahia hei hanga pūmua. I te wā whakawhiti, ka whakamahia he aho DNA hei tauira hei hanga RNA, ā, ka mau tonu hoki tēnei tukanga i te kaupapa o te hononga turanga, me te iti noa o te whakarerekētanga: i roto i te RNA, ka whakakapia te uracil (U) e te thymine (T). Nō reira, i roto i te RNA, ka honoa te A ki te U.
Te Ira Tangata me te Whanaketanga
He maha ngā wā ka uru ngā whakarerekētanga ira ki ngā panonitanga o te takirua turanga. I ētahi wā, ka puta ngā hapa, pērā i te whakakapinga o tētahi turanga ki tētahi atu. Ehara i te mea he kino ngā whakarerekētanga katoa; ka taea e ētahi te whakarato i ngā painga whanaketanga. Ka whakawhirinaki te whanaketanga ki ngā panonitanga ira i roto i te wā, ā, i roto i tēnei horopaki, ko te ngāwari e āhei ai ngā whakarerekētanga te puta he mahi nui.
Ngā tono i roto i te Hangarau Koiora
Te Hangarau Ira
Ko te hangarau koiora hou e whakawhirinaki nui ana ki te ariā o te takirua turanga. Hei tauira, ko te CRISPR-Cas9, he hangarau whakatika ira atamai, e whakamahi ana i te takirua turanga hei kimi me te whakarerekē i ngā wāhanga motuhake o te DNA ūnga. Ka taea e tēnei taputapu ngota ngota te kimi i ngā raupapa turanga motuhake i roto i te ira me te mahi tapahi ira, i ngā whakarerekētanga rānei me te tino tika.
Hangarau PCR (Polymerase Chain Reaction)
He tikanga taiwhanga whānui te PCR mō te whakanui i ngā wāhanga DNA. E whakawhirinaki ana tēnei tukanga ki te hononga turanga hei whakanui tere i ngā raupapatanga DNA. Kua hangaia ngā paraime i roto i te tukanga PCR hei hono atu ki te raupapa turanga ūnga, hei tīmata i te tukanga whakanui.
Te Whakamātautau me te Tātaritanga Ira
I roto i ngā mara hauora me ngā mahi taihara, he maha ngā wā ka whakamahia e te whakamātautau ira te mātāpono o te takirua turanga hei tautuhi i te raupapatanga DNA o te tangata. Mā te tautuhi i ngā momo āhuahanga nucleotide kotahi (SNP), i ngā rerekētanga takitahi rānei i roto i te takirua turanga kotahi i roto i te DNA, ka taea te whakarato i ngā mōhiohio hauora nui e pā ana ki te āheinga ki ētahi mate.
Ngā Wero me te Ao o Muri Mai
Ahakoa ko ngā ture o te takirua turanga te tūāpapa matua o ngā ira katoa, he nui tonu ngā mea kāore anō kia akohia mō ngā whanaketanga o ēnei takirua i roto i ngā taiao noho rerekē. Ahakoa he iti ake te kitea o ngā rerekētanga mai i ēnei ture, kei reira anō hoki, ā, ka taea te whakarato i ngā māramatanga hou ki ngā huarahi rongoā, ki te whakarerekētanga ira rānei. Hei tāpiri, ko ngā mahi ki te wetewete i ngā hanganga DNA uaua ake, tae atu ki ngā taunekeneke epigenetic me te hanganga supercoiled toru-ahu o ngā chromosomes, e tohu ana i tētahi rohe hou i roto i te koiora ngota.
Hei whakamutunga, ko ngā ture o te takirua turanga he mātāpono taketake e kore e hanga noa i te pūtake o te hanganga DNA engari e whakarato ana hoki i te turanga mō ngā tukanga koiora nui. Mai i te pumau ira ki te auahatanga hangarau koiora me te ahunga whakamua hauora, kei te whānui haere tonu tō tātou māramatanga ki ēnei ture, e whakatakoto ana i te ara mō ngā kitenga whakamiharo ake.
