Yuav ua li cas muaj ntau yam chromosomes nyob rau hauv tib neeg?

Chromosome - ntxwv thiab tej lub caij ntawm lub cell nucleus, muaj lub noob. Lub npe "chromosome" yog muab los ntawm cov Greek lus (Chroma - coloration thiab xim Soma - lub cev), thiab vim lub fact tias thaum lub sij hawm cell division, lawv quaj tawv heev tsuas nyob rau hauv lub xub ntiag ntawm yooj yim dyes (e.g., aniline).

Muaj ntau zaum, los ntawm thaum pib ntawm lub XX xyoo pua, xav txog tshaj rau lo lus nug: "Yuav ua li cas muaj ntau yam chromosomes nyob rau hauv tib neeg." Yog li ntawd kom txog rau thaum 1955 tag nrho cov "minds" tau convinced tias cov chromosomes nyob rau hauv tib neeg yog 48, piv txwv li, 24 officers. Yog vim li cas yog hais tias ua The-aufiluas Neeg pleev kob (Texas kawm) wrongly pom lawv nyob rau hauv preparative noob qis seem ntawm cov neeg uas raug castrated los ntawm ib tug lub tsev hais plaub kev txiav txim siab (nyob rau hauv 1921). Nyob rau hauv lub neej yav tom ntej, lwm zaum siv ntau ntsuas txoj kev, muaj kuj tuaj mus rau qhov no lub tswv yim. Txawm tsim ib txoj kev rau lub sib cais ntawm lub chromosomes, tus neeg tshawb fawb tsis cam lub txiaj ntsim ntawm Neeg pleev kob. Zaum tau pom ib tug yuam kev Albert Levan thiab Joe Hin Tyo nyob rau hauv 1955 uas meej suav, yuav ua li cas muaj ntau yam officers ntawm chromosomes nyob rau hauv tib neeg, namely - 23 (yog hais tias tus xam siv ntau niaj hnub siv tshuab).

Somatic thiab kab hlwb muaj ib tug ua txawv cov ntawm chromosomes los ntawm lub hom, uas tsis tau hais tias hais txog cov morphological nta ntawm chromosomes, uas yog qhov. Somatic hlwb muaj ib tug muab ob npaug rau (diploid), uas yog muab faib mus rau hauv ib tug khub ntawm zoo tib yam (homologous) chromosomes uas yog zoo xws li cov nyob rau hauv morphology (qauv) thiab loj. Ib feem ntawm nws txiv lub yeej ib txwm rau lwm yam - niam keeb kwm. Qhov chaw mos tib tib neeg lub hlwb (gametes) yog haploid (tib) set ntawm chromosomes. Yog hais tias fertilization yuav siv sij hawm qhov chaw lawv ua ke nyob rau hauv ib tug zygote nucleus haploid poob lawm ntawm cov txiv neej thiab poj niam gametes. Qhov no restores lub ob txheej. Nws yog tau hais nrog certainty yuav ua li cas muaj ntau yam chromosomes ib tug neeg - lawv cov 46, nrog 22 officers ntawm autosomes thiab ib tug khub ntawm ib - nrog txiv neej pw chromosomes (allosome). Pw ua ke sib txawv yog - ob qho tag nrho morphological thiab yam ntxwv (muaj pes tsawg leeg cov noob). Nyob rau hauv tus poj niam lub cev muaj ib tug khub gonosom ob X chromosomes (XX-khub), thiab tus txiv neej - ib tug x- thiab Y-chromosome (XY-Khub).

Morphologically, kho chromosomes thaum lub sij hawm cell division, lawv yog ob npaug (nrog rau cov kev zam ntawm kab hlwb nyob rau hauv uas doubling tshwm sim). Qhov no yog pheej rov qab ua ntau lub sij hawm, tab sis cov kev hloov nyob rau hauv lub chromosome txheej yog tsis cai. Qhov tseem hnov chromosome ntawm ib qho ntawm cov theem ntawm cell division (metaphase). Nyob rau hauv no theem lub chromosomes yog sawv cev los ntawm ob longitudinally phua formations (tus muam chromatids) yog roj thiab ua ke nyob rau hauv lub thiaj li hu ua thawj constriction los yog tsenromery (a yuav tsum tau caij ntawm ib tug chromosome). Hu telomeres ntawm lub chromosome xaus. Structurally tib neeg chromosome hais DNA (deoxyribonucleic acid) uas encodes noob muaj nyob rau hauv lawv cov muaj pes tsawg leeg. Noob, nyob rau hauv lem, muab lus qhia txog tej kev kos npe rau.

Yuav ua li cas muaj ntau yam chromosomes ib tug neeg yuav yog nyob ntawm seb nws ib tug neeg txoj kev loj hlob. Muaj tej yam raws li aneuploidy (hloov nyob rau hauv lub xov tooj ntawm ib tug neeg chromosomes) thiab polyploidy (tus naj npawb ntawm haploid poob lawm ntau tshaj diploid). Cov yav tas yog ob peb hom: tsis homologous chromosomes (monosomy) los yog cov tsos ntawm ntxiv chromosomes (trisomy - ib tug ntxiv, tetrasomiya - ob ntxiv, thiab lwm yam). Tag nrho cov no yog ib lub txim ntawm genomic thiab chromosomal change, uas yuav ua tau kom pathological tej yam kev mob xws li: Down syndrome, Klinefelter syndrome, Turner Shereshevkogo thiab lwm yam kab mob.

Yog li, tsuas yog lub thib nees nkaum xyoo pua tau muab cov lus teb rau tag nrho cov lus nug, thiab tam sim no yuav ua li cas muaj ntau yam chromosomes ib tug neeg paub txhua txhua kawm ntawv cov neeg ntawm ntiaj chaw ntiaj teb. Nws yog nyob rau dab tsi yuav tsum muaj pes tsawg leeg ntawm 23 officers ntawm chromosomes (XX los yog XY), nws nyob ntawm tus txiv neej pw ntawm tus me nyuam, thiab nws yog txiav txim ntawm fertilization, thiab txuas cov poj niam thiab txiv neej nrog txiv neej pw lub hlwb.