How okutodza dzakawanda vanhu?

Mashoko okutodza - STRUCTURAL uye dzichipfekeka vanzwe sero musimboti, kuitika kwemajini. The zita "chromosome" rinobva pashoko rechiGiriki mashoko (Chroma - dziberekane uye ruvara sōma - muviri), uye nokuda kuti panguva sero nokupesana, ivo zvikuru yakasvibiswa pamberi dzinokosha madhayi (semuenzaniso, aniline).

Masayendisiti akawanda, kubvira pakutanga XX remakore, akafungisisa pamusoro mubvunzo: ". okutodza Vangani muvanhu" Saka kusvikira 1955 ose "pfungwa" vaiva nechokwadi kuti nhamba okutodza kwevanhu 48, kureva, 24 maviri. Chikonzero chaiva chokuti Theophilus Painter (Texas nyanzvi) vakafurira akavawana vari preparative testis zvikamu vanhu vakanga akakuvadzwa nokuda chisarudzo dare (muna 1921). Mune ramangwana, mamwe masayendisiti vachishandisa siyana kuyerwa nzira, vakasvikawo pfungwa iyi. Kunyange dzakabudirira nzira nekuti akazvitsaurira ari okutodza, vatsvakurudzi havana dambudziko pamusana Painter. Masayendisiti akawana chikanganiso Albert Levan uye Joe Hin Tyo muna 1955 kuti zvakarurama kuverengwa, sei majoko akawanda okutodza muvanhu, zvinoti - 23 (kana dzemaitirwe vashandiswe yazvino).

Somatic uye nembeu masero ane zvakasiyana vanochengeta okutodza kubva mhando, risingagoni akati pamusoro morphological zviri okutodza, zviri kugara. Somatic Masero ane miviri (diploid), iro rakakamurwa vachipiwa fanana (homologous) okutodza yakafanana iri Morphology (Chimiro) uye kukura. Chimwe chikamu nguva dzose mumwe yababa vake - rwaamai mavambo. masero (gametes) chete nhengo dzokubereka hwevanhu vari haploid (kuroora) yakatarwa okutodza. Kana pakusangana inoitika navo pamwe chete zygote musimboti haploid anogadza vechirume gametes. Izvi anodzoreredza kaviri yakatarwa. Zvinokwanisika kutaura chokwadi vangani okutodza munhu - avo 46, pamwe 22 yegwara autosomes uye mumwe peya chete - bonde okutodza (allosome). Sex Kusiyana - zvose morphological uye STRUCTURAL (sezvamunoita magene). In hadzi muviri unotora peya gonosom X okutodza maviri (XX-vaviri), uye hono - imwe X- uye Y-chromosome (xy-Pair).

Morphologically, akachinjwa okutodza panguva muchitokisi nokupesana, izvo kaviri (kunze utachiona masero umo doubling kunoitika). Izvi inodzokororwa kakawanda, asi kuchinja ari chromosome yakatarwa haina kuchengetwa. Chinonyanya kuoneka chromosome rimwe nzendo muchitokisi weboka (metaphase). In danho iri chromosome anomiririrwa maviri longitudinally akatsemura idzodzo (hanzvadzi chromatids), izvo taper uye ikashandiswa mune dzinonzi chikuru constriction kana tsenromery (chromosome kunyorerana maatomu akafanana). Akadana telomeres of chromosome kumugumo. Zvayakaita chromosome munhu vakaisawo DNA (deoxyribonucleic acid) iyo inofananidzira majini re sezvamunoita yavo. Majini, akavapindurawo, kupa ruzivo pamusoro chero chaiyo chiratidzo.

Vangani okutodza munhu kuda kuvimba kwake nomumwe ebudiriro. Kune zvinhu zvakadai aneuploidy (shanduko kwenhamba munhu okutodza) uye polyploidy (nhamba haploid seti kupfuura diploid). kurasikirwa homologous okutodza (monosomy) kana chitarisiko: yokupedzisira ane marudzi mazhinji mamwe okutodza (- imwe zvokuwedzera, tetrasomiya - maviri zvokuwedzera, etc. Trisomy). Zvose izvi ndizvo migumisiro genomic uye chromosomal kunotouraya, izvo zvingaita kuti pathological ezvinhu akadai: syndrome, Klinefelter urwere, Turner Shereshevkogo nezvimwe zvirwere.

Saka, chete remakore rechimakumi maviri akapa mhinduro kumibvunzo yose, uye ikozvino sei okutodza zhinji munhu anoziva ose mugari vakadzidza kubva Nyika. Chiri chii chichava Kuronga 23 maviri okutodza (XX kana xy), izvozvo zvinoenderana zvepabonde mwana, uye akatsunga panosangana uye confluence munhukadzi uye vanhurume masero.