Caj ntaub ntawv: recessive thiab hom noob

Yuav ua li cas yog ib tug noob?

Noob - ib tug txhais ib theem zuj zus ntawm nucleotides dezoksiribonuklinovoy acid nyob rau hauv uas lub encoded genetic ntaub ntawv (ntaub ntawv hais txog cov thawj cov qauv ntawm cov protein molecules). DNA Molecule - ob chav tso tseg. Txhua lub chains muaj ib tug meej nucleotide ib theem zuj zus. Lub hom qauv ntawm cov protein, uas yog tus naj npawb thiab ib theem zuj zus ntawm cov amino acids, plays ib tug decisive luag hauj lwm nyob rau hauv raws roj ntsha sijhawm. Yuav kom encode ntaub ntawv kom zoo thiab tsis tu ncua nyeem ntawv, lub noob yuav tsum muaj ib tug pib codon, txiav codon thiab paub codons ncaj qha encode cov yam amino acid ib theem zuj zus. Codons roos peb sib law liag nucleotides uas encode ib tug amino acid. Codons UAA, UAG, Uga yog npliag thiab ua tsis tau code rau ib yam ntawm cov uas twb muaj lawm amino acids, thaum nyeem ntawv lub replication txheej txheem yog nres. Qhov seem codons (nyob rau hauv tus nqi ntawm cov 61 daim) encode amino acids.

Faib lub hom thiab recessive noob. Hom noob - ib theem ntawm nucleotides uas muab ib tug manifestation ntawm ib tug feature (tsis hais dab tsi zoo ntawm cov noob yog nyob rau hauv tib khub (xa recessive los yog hom noob)). Lub recessive noob yog ib tug nucleotide ib theem zuj zus, uas qhia txog ib tug phenotype feature no tsuas tau nyob rau hauv lub xub ntiag ntawm ib tug khub ntawm tib recessive noob.

Cov ntaub ntawv no yuav tsuas caj ntaub ntawv uas yuav kis tau los ntawm tiam mus rau tiam. Txawm li cas los, tsuas yog ib tug ua ke ntawm noob variants nyob qhia ntawm ib tug kev zoo losis phem. Yog hais tias cov khub yog recessive thiab hom noob, nws yuav tshwm sim phenotypically vaj tse kho hom. Thiab tsuas qhia lawv cov lus qhia nyob rau hauv cov ntaub ntawv ntawm ib tug ua ke ntawm ob recessive noob. Hais tias yog, hom noob suppresses recessive.

Qhov twg muaj noob?

Cov ntaub ntawv uas peb muaj noob los ntawm peb pog koob yawg koob. Cov no muaj xws tsis tsuas cov niam txiv tab sis kuj yawg thiab lwm cov ntshav txheeb ze. Cov noob tso yog tsim nyob lub hlws ris ntawm cov phev thiab qe, los yog es - thaum phiajcim X thiab Y chromosomes los yog ob tug X chromosomes. Los ntawm cov txiv muaj peev xwm coj cov ntaub ntawv rau ob qho tib si X thiab Y chromosome, thaum los ntawm nws niam - tsuas yog lub X chromosome.

Nws yog lub npe hu hais tias tus X chromosome muaj cov lus qhia ntxiv kom cov poj niam muaj ntau resistant rau cov kab mob ntawm cov xwm sib txawv tshaj cov txiv neej pejxeem. Nyob rau hauv kev tshawb xav, tus xov tooj ntawm cov me nyuam mos thiab cov tub hluas ntxhais yuav tsum tau sib npaug zos, tab sis nyob rau hauv kev xyaum, cov tub hluas yuav yug los. Raws li ib tug tshwm sim, nyob rau hauv lub hauv paus ntawm cov ob cov lus tseeb, muaj ib tug balancing ntawm ob kuj. Ntau dua fertility ntawm cov txiv neej pejxeem yog compensated los ntawm ib tug ntau dua kuj mus rau ntau yam influences, cov yam ntxwv ntawm cov poj niam.

genetic engineering

Tam sim no peb ua nws kim heev kev tshawb fawb ntawm cov kev tshuaj ntsuam genetic khoom. Cov kev ntawm kev rho tawm, thiab cloning ntawm ib tug neeg cov noob hybridization. Qhov no yog - lub feem ntau kauj ruam tseem ceeb nyob rau hauv kev tsim lub neej tom ntej. Tej xim rau qhov teeb meem no tau provoked ib tug ntau ntawm speculation thiab kev ntshaw. Tom qab kev tshawb kom ntxaws tej zaum yuav pab kom noob neej los mus npaj lub zog thiab nta cov tiam tom ntej, kom tsis txhob muaj ntau yam kab mob thiab loj hlob nruab nrog cev thiab lawv lub nruab rau kev sib hloov.