Zingaphi zofuzo ebantwini?

Chromosome - isakhi kwaye zisebenza yeseli ngumongo, eliquka zofuzo. Igama "chromosome" livela amagama Greek (chrōma - kombala kunye nombala SOMA - umzimba), kwaye ngenxa yokuba ngexesha hlula yeseli, bagcoba kakhulu phambi iidayi ezisisiseko (umz, aniline).

izazinzulu ezininzi, ukususela ekuqaleni kwenkulungwane XX, wacinga phezu mbuzo: ". zofuzo Bangaphi abantu" Ngoko de kwangowe-1955 zonke "iingqondo" baqiniseka ukuba inani zofuzo kubantu ngu 48, oko kukuthi, 24 ngababini. Isizathu kukuba Teofilus Peynter (umphengululi Texas) ngokungafanelekanga wabafumana kumacandelo iba lityhalarha preparative abantu abo ayethenwa sisigqibo senkundla (ngo-1921). Kwixa elizayo, ezinye izazinzulu ukusebenzisa eyahlukileyo womlinganiselo iindlela, Kwaye ukuze lo mbono. Nokuba liphuhlise indlela ngokuba ukwahlula izinto zofuzo, abaphengululi akazange umngeni ngenxa Umpeyinti. Izazinzulu ziye zafumanisa impazamo uAlbert Levan Joe Hin Tyo ngo-1955 ukuba ngokuchanekileyo ekuthini, zazingaphi izibini zofuzo abantu, oko kukuthi, - 23 (ukuba ekubalwa ezisetyenziswayo wesimanje technology).

Somatic kunye lwegciwane iiseli ziqulathe isethi eyahlukileyo zofuzo ukusuka iintlobo, apho akunakuthethwa malunga neempawu morphological zofuzo, ezo rhoqo. iiseli Somatic ukuba ngokuphindwe kabini (diploid) lwahlulwe lwaba iperi (homologous) zofuzo elifanayo ziyafana morphology (isakhiwo) kunye nokubaluleka. Enye inxalenye kusoloko enye kayise - imvelaphi koomama. Ezikumalungu okuzala iiseli yabantu efanayo (gametes) are haploid iseti (single) zofuzo. Ukuba ekukhulelweni kuthatha kunye uwabeke enye elilodwa nucleus iiseti haploid kwamadoda gametes ababhinqileyo. Oku ulibuyele isethi kabini. Kuyenzeka ukuba kuthi ngokuqinisekileyo zingaphi zofuzo umntu - zabo 46, kunye ngababini 22 autosomes kunye enye iperi single - zofuzo sex (allosome). Umahluko zesini - zombini morphological beemeko (genes composition). Xa umzimba imazi iqulathe isibini gonosom X zofuzo ezimbini (XX-isibini), kwaye inkunzi - X- omnye Y-chromosome (XY-Iperi).

Morphologically, zofuzo zatshintshwa kwisahlulo iseli, ukuba kabini (ngaphandle iiseli intsholongwane apho kwenzeka buya). Oku phindwa amaxesha amaninzi, kodwa utshintsho kwiseti chromosome ayikho ulandelwe. Le chromosome ephawuleka kwenye amanqanaba kwisahlulo iseli (metaphase). Kwesi sigaba chromosome simelwe kwiziseko ezimbini longitudinally yahlula (udade chromatids), apho Taper kwaye zidibene kwi constriction zaseprayimari ekuthiwa-okanye tsenromery (chromosome into ayikokubambana). telomere ebizwa eziphelweni chromosome. Ngokokwakheka chromosome yabantu thaca DNA (deoxyribonucleic acid) apho buqonda genes ifakiwe ukwakhiwa kwawo. Yemfuza, nto, ukunika ulwazi malunga nayiphi na isibonakaliso esithile.

Bangaphi zofuzo umntu uya kuxhomekeka kuphuhliso ayo. Kukho izinto ezinjalo njengoko aneuploidy (utshintsho kwinani zofuzo ngamnye) kunye polyploidy (inani iiseti haploid ngaphezu diploid). Le yokugqibela yi kweentlobo ezininzi: ilahleko zofuzo homologous (monosomy) okanye imbonakalo zofuzo extra (trisomy - omnye elingaphezulu, tetrasomiya - ezimbini ezongeziweyo, njalo njalo). Konke oku ngenxa genomic kunye chromosomal yemfuza, nto leyo inokukhokelela kwiimeko zophendlo lwezifo ezifana: Down syndrome, Klinefelter syndrome, Turner Shereshevkogo kunye nezinye izifo.

Ngenxa yoko, kuphela kwinkulungwane yamashumi amabini wanika iimpendulo yonke imibuzo, yaye ngoku zingaphi zofuzo umntu uyazi yonke ummi ofundileyo uMhlaba. It is on uya kuba yintoni na nokwakhiwa ngababini 23 zofuzo (XX okanye XY), kuxhomekeke besini yomntwana, kwaye uzimisele ekukhulelweni, kwaye intlanganisela iiseli zesini ababhinqileyo kunye abangamadoda.