Kev hloov pauv yog qhov hloov pauv hauv cov genome tau txais los ntawm cov xeeb leej xeeb ntxwv. Cov kev hloov pauv hauv cov khoom qub txeeg qub teg nyob rau hauv lub cell muab faib ua peb pawg. Nyob rau hauv genomic, chromosomal thiab noob. Nws yog hais txog cov noob los yog, ua lwm yam lus, taw tes hloov pauv uas yuav tau tham. Nws yog nws uas suav tias yog qhov teeb meem tiag tiag hauv cov noob caj noob ces niaj hnub no.
Kev hloov pauv yog dab tsi?
Kev hloov noob caj ces muaj ntau dua li chromosomal thiab polyploid (genomic). Nws yog dab tsi? Point kev hloov pauv yog qhov hloov pauv, tshem tawm, lossis tso rau ntawm ib qho nitrogenous puag (pyrimidine derivatives) nyob rau hauv qhov chaw ntawm lwm qhov. Cov kev hloov pauv tshwm sim hauv cov tsis-coding (quav) DNA thiab feem ntau tsis tshwm sim lawv tus kheej.
Cov txheej txheem ntawm kev hloov pauv tshwm sim thaum DNA tau sib npaug hauv cov cell nyob (replication), hla (piv cov cheeb tsam homologous ntawm chromosomes) lossis lwm lub sijhawm ntawm lub voj voog ntawm tes. Thaum lub sij hawm rov tsim dua ntawm cov qauv ntawm tes, kev hloov pauv thiab kev puas tsuaj rau DNA raug tshem tawm. Tsis tas li ntawd, lawv tus kheej tuaj yeem ua rau muaj kev hloov pauv. Piv txwv li, yog tias chromosome tawg, ces thaum nwsrov qab, ib feem ntawm nucleosite phosphate khub poob.
Yog tias cov txheej txheem rov tsim dua tshiab rau qee yam tsis ua haujlwm zoo txaus, kev hloov pauv sai sai. Yog tias kev hloov pauv tau tshwm sim hauv cov noob lub luag haujlwm kho, kev ua haujlwm ntawm ib lossis ntau lub ntsiab lus yuav cuam tshuam. Yog li ntawd, tus naj npawb ntawm kev hloov pauv yuav nce zuj zus. Txawm li cas los xij, qee zaum qhov cuam tshuam tsis zoo tshwm sim, thaum qhov kev hloov pauv ntawm cov noob ntawm cov enzymes rov ua dua tshiab ua rau txo qis qhov zaus ntawm kev hloov pauv ntawm lwm cov txheej txheem ntawm kev hloov pauv.
Feem ntau qhov kev hloov pauv, zoo li lwm tus, muaj teeb meem. Lawv tshwm sim nrog cov cim tseem ceeb tshwm sim tsis tshua muaj. Tab sis lawv yog lub hauv paus ntawm cov txheej txheem ntawm evolution.
Type of point mutations
Kev faib tawm ntawm cov noob hloov pauv yog raws li kev hloov pauv uas hloov pauv nitrogenous puag muaj nyob rau triplet. Clinically, lawv tau tshwm sim los ntawm cov tsos mob ntawm cov kab mob metabolic hauv lub cev. Ntau yam ntawm cov noob los yog taw tes hloov pauv:
- Kev hloov pauv. Cov tsiaj no hais txog cov txheej txheem ntawm kev hloov cov genome, nyob rau hauv uas cov qauv ntawm cov caj ces code encodes ib tug txawv amino acid. Nyob ntawm seb cov khoom ntawm cov protein sib txawv li cas ntawm cov proteins qub, qhov kev lees paub, ib feem tau txais thiab tsis lees txais kev hloov pauv tsis raug cai yog qhov txawv.
- Nonsense mutation - hloov pauv hauv DNA ib ntus, ua rau lub sijhawm kawg ntawm kev sib txuas ntawm cov protein. Cov kab mob uas lawv tuaj yeem ua rau muaj xws li cystic fibrosis, Hurler syndrome thiab lwm yam.
- Silence mutation - tripletcodes rau tib amino acid.
Base substitution mutations
Nws muaj ob chav kawm tseem ceeb ntawm nitrogen hloov pauv hloov pauv.
- Kev hloov pauv. Txhais los ntawm Latin, kev hloov pauv txhais tau tias "tsav". Hauv cov noob caj noob ces, tus nqi yog hais txog kev hloov pauv, uas ib qho organic compound, purine derivative, hloov los ntawm lwm tus, piv txwv li, adenine rau guanine.
- Kev hloov pauv - hloov pauv ntawm lub hauv paus purine (adenine) nrog pyrimidine puag (cytosine, guanine). Lub hauv paus hloov pauv kuj tau faib ua lub hom phiaj, tsis yog lub hom phiaj, qeeb.
Qhib nyeem ncej hloov pauv hloov pauv
Cov kab ntawv nyeem ntawm cov noob yog cov kab ke ntawm nucleoside phosphates muaj peev xwm ntawm kev nkag mus rau cov protein. Kev hloov pauv yog sib piv nrog cov complex thiab cais raws li hauv qab no:
- Kev tshem tawm yog qhov poob ntawm ib lossis ntau dua nucleoside phosphates los ntawm DNA molecule. Raws li localization ntawm qhov chaw ploj, kev tshem tawm tau muab faib ua sab hauv thiab davhlau ya nyob twg. Qee zaum, hom kev hloov pauv no ua rau muaj tus mob schizophrenia.
- Insertion yog ib qho kev hloov pauv uas tshwm sim los ntawm kev nkag ntawm nucleotides rau hauv DNA ib ntus. Kev txav mus los tuaj yeem nyob hauv genome, tus neeg sawv cev ntawm tus kab mob extracellular tuaj yeem ua ke.
Qee zaum, kev hloov pauv tshwm sim hauv cov seem ntawm DNA. Cov no yog hu ua kev hloov pauv tsis yog lub hom phiaj.
Gene mutations tsis tas yuav txhim kho tam sim tom qab qhov cuam tshuam tsis zoo ntawm mutagen. Qee zaum kev hloov pauv tshwm sim tom qab ob peb lub hliskev rov ua dua tshiab.
Kev tshwm sim
Qhov ua rau ntawm qhov hloov pauv tau muab faib ua ob pawg:
- Spontaneous - txhim kho yam tsis muaj laj thawj. Qhov zaus ntawm kev hloov pauv ntawm tus kheej yog los ntawm 10⁻¹² txog 10⁻⁹ rau txhua DNA nucleoside phosphate.
- Induced - tshwm sim los ntawm kev cuam tshuam ntawm lwm yam: hluav taws xob, kab mob, tshuaj lom neeg.
Hloov hom kev hloov pauv tshwm sim rau ntau yam. Kev hloov pauv hauv hom frameshift yog qhov tshwm sim.
Piv txwv ntawm cov noob hloov pauv
Cov txheej txheem hloov pauv yog qhov hloov pauv uas ua rau muaj ntau yam kab mob. Txog niaj hnub no, txawm tias tsis tshua muaj, muaj kev hloov pauv tsis tu ncua ntawm cov khoom siv caj ces ntawm lub cev ntawm lub cev.
Piv txwv ntawm qhov hloov pauv:
- YProgeria. Ib qho tsis tshua muaj tshwm sim los ntawm kev laus ntxov ntxov ntawm txhua lub cev thiab lub cev tag nrho. Cov neeg uas muaj qhov kev hloov pauv no tsis tshua muaj nyob tshaj lawv thirties. Cov kev hloov pauv cuam tshuam rau kev loj hlob ntawm cov hlab ntsha, lub plawv pathologies. Strokes thiab plawv nres yog qhov ua rau tuag rau cov neeg mob Progeria.
- Hypertrichosis. Cov neeg uas muaj tus mob Ambras yog tus cwj pwm los ntawm kev nce plaub hau. Cov nroj tsuag tshwm sim ntawm lub ntsej muag, xub pwg.
- Marfan syndrome. Ib qho kev hloov pauv ntau tshaj plaws. Cov neeg mob tau tsim cov ceg tawv tsis sib xws, kev sib xyaw ntawm cov tav tau pom, vim qhov tshwm sim ntawm lub hauv siab hauv siab.
Kev hloov pauv hauv cov noob caj noob ces niaj hnub
Human evolution tsis yogtxwv los ntawm yav dhau los. Cov txheej txheem uas ua rau muaj kev hloov pauv txuas ntxiv ua haujlwm niaj hnub no. Kev hloov pauv yog ib txoj hauv kev uas muaj nyob hauv cov kab mob uas muaj sia nyob, uas qhia txog kev hloov pauv ntawm txhua yam ntawm lub neej thiab muaj cov ntaub ntawv hloov pauv caj ces.
Txiv Neej yog thaj chaw tseem ceeb ntawm biology. Tib neeg siv txoj hauv kev caj ces hauv kev yug tsiaj thiab qoob loo. Los ntawm kev xaiv cov pej xeem zoo tshaj plaws, ib tus neeg hla lawv, tsim cov ntau yam zoo tshaj plaws thiab cov yug me nyuam uas muaj qhov tsim nyog zoo. Cov noob caj noob ces tau ua tiav cov txiaj ntsig zoo hauv kev piav qhia qhov xwm txheej ntawm noob neej. Tab sis hmoov tsis zoo, nws tseem tsis tuaj yeem txiav txim siab kev hloov pauv ywj pheej hauv genome.
Gene thiab point kev hloov pauv yog qhov sib txawv, txhais tau tias kev hloov pauv hauv ib lossis ntau dua nucleotides. Hauv qhov no, ib lub hauv paus nitrogen tuaj yeem hloov tau los ntawm lwm qhov, poob tawm, sib npaug lossis tig 180 °.
Peb tuaj yeem ntseeg tau hais tias qhov kev hloov pauv ntawm cov noob thiab yuav luag txhua qhov aberrations (kev sib txawv ntawm cov qauv) ntawm chromosomes yog qhov tsis zoo rau tib neeg lub cev thiab rau cov pejxeem. Feem ntau chromosomal txawv txav uas tshwm sim thaum lub sij hawm embryonic txoj kev loj hlob ua rau loj congenital malformations. Kev hloov pauv ntawm cov ntsiab lus ua rau muaj kab mob hauv lub cev lossis lub cev tsis zoo.
Txoj haujlwm ntawm kev tshawb fawb yog los txiav txim siab yuav ua li cas tiv thaiv lossis tsawg kawg txo qhov yuav muaj kev hloov pauv thiab tshem tawm cov kev hloov pauv hauv DNA los ntawm genetic engineering.
