Mutational variability thiab hom change

Lub sij hawm "hloov" los ntawm Latin lo lus "mutatio", uas lus txhais tau tias - kev hloov los yog hloov. Mutational variability qhia ruaj khov thiab cuab kev hloov kho ntawm lub caj khoom uas yog tso tawm nyob rau hauv lub roj ntsha sijhawm. Qhov no yog thawj qhov link hauv ib cov saw tsim thiab pathogenesis ntawm roj ntsha kab mob. Qhov no tshwm sim tau tau nquag kawm nyob rau hauv lub thib ob ib nrab ntawm lub xyoo pua 20th, thiab tam sim no ntau thiab ntau koj yuav hnov hais tias cov mutational variability yuav tsum tau kawm raws li zoo raws li cov kev txawj ntse thiab kev nkag siab ntawm no mechanism yuav tus yuam sij rau overcoming tus teeb meem ntawm noob neej.

Muaj ob peb hom change nyob rau hauv lub hlwb. Lawv faib nyob rau hauv lub hom ntawm lub hlwb lawv tus kheej. Generative change tshwm sim nyob rau hauv lub kab hlwb, germline hlwb kuj ua ib ke. Tej kev hloov no yog pub thiab yog feem ntau pom nyob rau hauv cov xeeb ntxwv hlwb, los ntawm tiam mus rau tiam yog dhau ib tug xov tooj ntawm hloov uas thaum kawg los ua ib tug ua ntawm tus kab mob.

Somatic change yog asexual hlwb. Lawv peculiarity yog hais tias lawv yuav tshwm sim rau cov neeg uas tau tshwm sim. Xws li kev hloov yuav tsis pub rau lwm lub hlwb, tiam sis tsuas yog thaum muab faib nyob rau hauv ib lub cev. Somatic mutational variability yog manifested hnov thaum nws pib nyob rau hauv thaum ntxov ua sawv. Yog hais tias ib tug kev hloov tshwm sim nyob rau hauv thaum ntxov ua sawv ntawm crushing zygote, muaj yog ib tug loj cell kab txawv los ntawm txhua lwm yam genotypes. Raws li, qhov ntev ntawm lub hlwb yuav nqa cov kev hloov, xws kab mob no yog hu ua mosaic.

Theem ntawm kev tshuaj ntsuam genetic lug

Mutational variability yog manifested nyob rau hauv lub caj lug uas txawv txawv muaj ntau seem ntawm lub koom haum. Change yuav tshwm sim nyob rau noob, chromosome thiab genome qib. Nyob ntawm seb qhov kev hloov no thiab tej yam kev hloov.

Caj kev hloov kev cuam tshuam rau DNA qauv, uas nws hloov nyob rau molecular theem. Tej kev hloov, nyob rau hauv tej rooj plaub tsis muaj kev cuam tshuam cov nqi ntawm cov protein, piv txwv li, muaj nuj nqi tsis hloov. Tab sis nyob rau hauv lwm tus neeg mob, tej zaum yuav puas kev kawm ntawv uas twb tsis muaj protein ntau yuav ua tau nws txoj kev ua.

Hloov nyob rau chromosomal theem twb nqa ib tug loj kev hem thawj vim hais tias lawv muaj kev cuam tshuam cov tsim ntawm chromosomal kab mob. Cov tshwm sim ntawm no variation yog hloov nyob rau hauv cov qauv ntawm cov chromosomes, thiab muaj twb tau ob peb noob muab kev koom tes. Vim li no, tej zaum nws yuav hloov lub qub diploid teeb, uas nyob rau hauv lem yuav muaj ib feem nyob rau tag nrho cov DNA.

Genomic change li zoo raws li lub chromosome yuav ua rau cov tsim ntawm chromosomal kab mob. Piv txwv ntawm kev hloov nyob rau theem no - aneuploidy thiab polyploidy. Qhov no nce los yog txo nyob rau hauv lub xov tooj ntawm chromosomes uas rau ib tug neeg feem ntau yuav tsum tau tuag.

Noob change koom trisomy, signifying xub ntiag ntawm peb homologous chromosomes nyob rau hauv lub karyotype (nce nqi). Tej deflection tau nyob rau hauv lub tsim ntawm Edwards Syndrome thiab Down syndrome. Monosomy txhais tau tias lub xub ntiag ntawm xwb ib tug ntawm ob homologous chromosomes (txo nqi), zoo xa cov qub kev loj hlob ntawm lub embryo.

Qhov ua rau ntawm cov phenomena yog kev ua txhaum ntawm ntau theem ntawm kev loj hlob ntawm tus kab hlwb. Qhov no tshwm sim raws li ib tug tshwm sim ntawm qeeb anaphase - homologous chromosomes thaum lub sij hawm cell division txav mus rau tug, thiab ib tug ntawm lawv yuav kom mus. Muaj kuj yog lub tswvyim ntawm "uas tsis yog-disjunction", thaum lub chromosomes yuav tsis raug faib mus rau hauv theem ntawm mitosis los yog meiosis. Qhov no los tau nyob rau hauv lub manifestation ntawm kev ntshawv siab ntawm qhov ntau heev. Txoj kev tshawb no ntawm no phenomenon yuav pab mus rau unravel lub mechanisms ntawm, thiab tej zaum yuav ua rau nws tau mus twv seb thiab feem xyuam rau txoj cov dab.