Ngemva kokuba isazi saseMelika u-Eric S. Lander ehlongoza ngokusemthethweni i-nucleotide polymorphism (SNP) njengemaki yamangqamuzana esizukulwane sesithathu ngo-1996, i-SNP iye yasetshenziswa kabanzi ekuhlaziyeni isimilo sesimo sezomnotho, ukwakhiwa kwemephu yokuxhumanisa izakhi zofuzo, kanye nokuhlolwa kwezakhi zofuzo zabantu., Ukuhlonzwa kwengozi yezifo kanye nokubikezela, ukuhlolwa kwezidakamizwa komuntu ngamunye, nezinye izinkambu zocwaningo lwebhayoloji nezokwelapha.Emkhakheni wokuzalanisa izitshalo zemali, ukutholwa kwe-SNP kungabona ukukhetha kusenesikhathi kwezici ezidingekayo.Lokhu kukhetha kunezici zokunemba okuphezulu futhi kungagwema ngokuphumelelayo ukuphazanyiswa kwe-morphology kanye nezici zemvelo, ngaleyo ndlela kufinyeze kakhulu inqubo yokuzalanisa.Ngakho-ke, i-SNP idlala indima enkulu emkhakheni wocwaningo oluyisisekelo.

I-Single Nucleotide Polymorphism (I-Single Nucleotide Polymorphism, SNP) ibhekisela esenzakalweni sokuthi kunomehluko owodwa we-nucleotide endaweni efanayo ekulandelaneni kwe-DNA yabantu bohlobo olufanayo noma oluhlukile.Ukufakwa, ukususwa, ukuguqulwa kanye nokuguqulwa kwesisekelo esisodwa kungabangela lo mehluko.Esikhathini esedlule, incazelo ye-SNP yayihlukile kuleyo yokuguquguquka.I-locus ehlukile idinga ukuthi imvamisa yeyodwa yama-alleles esintwini inkulu kuno-1% ukuze ichazwe njengendawo ye-SNP.Kodwa-ke, ngokunwetshwa kwemibono yesimanje yezinto eziphilayo kanye nokusetshenziswa kobuchwepheshe, imvamisa ye-allele ayisesona isimo esidingekayo ukuze kukhawulwe incazelo ye-SNP.Ngokwedatha yokuhluka kwe-nucleotide eyodwa efakwe kusizindalwazi se-Single Nucleotide Polymorphisms (dbSNP) ngaphansi kweSikhungo Sikazwelonke Solwazi Lwe-Biotechnology (NCBI), ukufakwa/ukususwa kwe-low-frequency, ukuhluka kwe-microsatellite, njll.

Emzimbeni womuntu, imvamisa ye-SNP ingu-0.1%.Ngamanye amazwi, kunesilinganiso sesiza esisodwa se-SNP ngamapheya ayi-1000 ayisisekelo.Nakuba imvamisa yokwenzeka iphakeme ngokuqhathaniswa, akuwona wonke amasayithi e-SNP angaba omaka bekhandidethi abahlobene nezici.Lokhu kuhlobene kakhulu nendawo lapho i-SNP ivela khona.

Ngokwethiyori, i-SNP ingenzeka noma yikuphi ngokulandelana kofuzo.Ama-SNP avela esifundeni sekhodi angakhiqiza ukuguqulwa okufanayo kanye nokuguqulwa okungezona okufanayo, okungukuthi, i-amino acid iyashintsha noma ingashintshi ngaphambi nangemva kokuguqulwa.I-amino acid eshintshile ngokuvamile ibangela ukuthi iketango le-peptide lilahlekelwe umsebenzi walo wasekuqaleni (ukuguqulwa kwe-missense), futhi ingase futhi ibangele ukuhunyushwa kokuhumusha (ukuguqulwa kombhedo).Ama-SNP avela ezifundeni ezingafaki amakhodi nasezifundeni ze-intergenic angase athinte ukuhlanganiswa kwe-mRNA, ukwakheka kokulandelana kwe-RNA okungafaki amakhodi, kanye nokusebenza kahle okubophezelayo kwezinto ezilotshiweyo kanye ne-DNA.Ubudlelwano obukhethekile buboniswa emfanekisweni:

Izinhlobo ze-SNP:

Izindlela ezimbalwa ezijwayelekile zokuthayipha kwe-SNP nokuqhathanisa kwazo

Ngokwemigomo ehlukene, izindlela ezijwayelekile zokutholwa kwe-SNP zihlukaniswe izigaba ezilandelayo:

Ukuqhathaniswa kokuhlukaniswa kwezindlela zokuthola

Qaphela: Okusohlwini lwethebula okwamanje kusetshenziswa izindlela zokuthola ezivamile ze-SNP, ezinye izindlela zokubona ezifana ne-site hybridization (ASH), isandiso se-primer yesayithi elithile (ASPE), isandiso sesisekelo esisodwa (SBCE), ukusika isayithi elithile (ASC), ubuchwepheshe be-gene chip, ubuchwepheshe be-mass spectrometry, njll. azikahlukaniswa futhi ziqhathaniswe.

Izindleko kanye nesikhathi sokuhlanzwa kwe-nucleic acid kulezi zindlela ezimbalwa ezingenhla zokuthola i-SNP azinakugwenywa.Kodwa-ke, amakhithi ahlobene asekelwe kubuchwepheshe be-Foregene eqondile be-PCR angenza ngokuqondile i-PCR noma i-qPCR yokukhulisa amasampula angahlanzekile, okuletha ukunethezeka okungakaze kubonwe ekutholweni kwe-SNP.

Imikhiqizo yochungechunge lwe-PCR eqondile ye-Foregene ilula futhi icishe ishiye izinyathelo zokuhlanza isampula, okunciphisa kakhulu isikhathi nezindleko ezidingekayo ukuze kulungiswe izifanekiso.I-Taq polymerase eyingqayizivele inekhono elihle kakhulu lokukhulisa futhi ingakwazi ukubekezelela ama-inhibitor ahlukahlukene avela ezindaweni eziyinkimbinkimbi zokukhulisa.Lezi zici zinikeza isiqinisekiso sobuchwepheshe sokuthola imikhiqizo ethile enesivuno esikhulu.Ikhithi ye-Forgene Direct PCR/qPCR yezinhlobo ezihlukene zesampula, njengalezi: izicubu zezilwane (umsila wegundane, i-zebrafish, njll.), amaqabunga ezitshalo, imbewu (okuhlanganisa amasampula e-polysaccharides nama-polyphenol), njll.