Twins account rau ntau dua 90 feem pua ntawm ntau qhov kev yug. Muaj ob hom menyuam ntxaib – zoo tib yam (monozygotic) thiab fraternal (dizygotic). Txhawm rau tsim cov menyuam ntxaib zoo ib yam, ib lub qe fertilized (ovum) sib cais thiab tsim ob tus menyuam mos uas muaj cov ntaub ntawv caj ces tib yam.
Puas monozygotic txhais tau tias zoo ib yam?
Ib yam ntxaib tseem hu ua monozygotic ntxaib. Lawv tshwm sim los ntawm fertilization ntawm ib lub qe uas faib ua ob. Cov menyuam ntxaib zoo tib yam qhia tag nrho lawv cov noob thiab yeej ib txwm sib deev. Hauv qhov sib piv, cov kwv tij, los yog dizygotic, cov menyuam ntxaib tshwm sim los ntawm kev yug me nyuam ntawm ob lub qe sib cais thaum lub sij hawm cev xeeb tub.
Puas tsis zoo ib yam ntxaib monozygotic lossis dizygotic?
Ntxaib tuaj yeem yog yog monozygotic ('zoo tib yam'), txhais tau tias lawv tsim los ntawm ib lub zygote, uas sib cais thiab tsim ob lub embryos, lossis dizygotic ('tsis zoo ib yam' lossis 'fraternal'), txhais tau hais tias txhua tus ntxaib tsim los ntawm ib lub qe cais thiab txhua lub qe yog fertilized los ntawm nws tus kheej phev cell.
Dab tsi yog tus yam ntxwv ntawm tus menyuam ntxaib?
Ib leeg ntxaib
Cov khoom siv caj ces hu ua chromosomes hauv ob tus menyuam mos yog tib yam nkaus. Qhov no yog vim ob tus menyuam mos los ntawm tib lub qe thiab phev. Vim li no, ob tug me nyuam tau muab tib tug poj niam txiv neej thaum yug los thiab qhia tib yam caj ces, xws li qhov muag thiab cov plaub hau xim.
Koj puas tuaj yeem txiav txim siab yog tus tub hluas nkauj ntxaibkhub niam txiv yog cov menyuam ntxaib monozygotic lossis dizygotic ntxaib?
Tub/ntxhais ntxaib yeej ib txwm ua phooj ywg los yog (dizygotic); lawv tsuas tuaj yeem tsim los ntawm ob lub qe sib cais uas fertilized los ntawm ob lub phev cais. … Ib pawg tub/ntxhais ntxaib: Tsuas yog ib leeg xwb (dizygotic), raws li tus tub/ntxhais ntxaib tsis tuaj yeem zoo ib yam (monozygotic)
