Kodi DNA ambiri mwa anthu?

Khromozomu - structural ndi zinchito mchitidwe wa phata khungu, kupanga chibadwa. Dzina "khromozomu" anachokera ku mawu achigiriki (chrōma - ochekenera, mtundu ndi sōma - thupi), ndi chifukwa chakuti pa magawano selo kwambiri akuda pamaso pa nsalu zofunika (mwachitsanzo, aniline).

Asayansi ambiri, kuyambira chiyambi cha XX atumwi, akusinkhasinkha funso: "Kodi DNA anthu." Kotero kufikira 1955 onse "maganizo" ankakhulupirira kuti chiwerengero DNA anthu 48, ie, 24 awiriawiri. chifukwa chinali Teofilus Peynter (Texas katswiri) molakwika nawapeza ali ku zigawo preparative testis wa anthu amene wofulidwa ndi zochita bwalo (mu 1921). M'tsogolo, asayansi ena pogwiritsa ntchito njira zosiyanasiyana muyeso, kuti naonso maganizo. Ngakhale njira ina kwa kulekana kwa DNA ndi ofufuza sanali kutsutsa zotsatira za zojambulajambula. Asayansi apeza kulakwitsa Albert Levan ndi Joe Hin Tyo mu 1955 kuti molondola otero, mmene awiriawiri ambiri DNA anthu, ndicho - 23 (ngati mawerengedwe ntchito zamakono zambiri).

Somatic ndi nyongolosi maselo muli osiyana ya DNA ku mitundu, amene sitinganene za morphological mbali ya DNA, amene nthawi zonse. maselo Somatic ndi awiri (diploid), amene magawo awiri ofanana DNA (magazi) ofanana mu kafukufuku wakapangidwe kazachilengedwe (loukitsa) ndi kukula. Mbali ina ya nthawi wina atate wake - chiyambi akuchikazi. Maliseche omwewo maselo a anthu (gametes) ndi haploid (osakwatira) ya DNA. Ngati ubwamuna dzira awo kucheza limodzi la zygote phata haploid akanema wa mwamuna ndi mkazi gametes. Izi limabwezeretsa pawiri akonzedwa. N'zotheka kuti motsimikiza angati DNA munthu - awo 46, ndi awiriawiri 22 autosomes ndi peyala imodzi ya wosakwatiwa - kugonana DNA (allosome). Kugonana kusiyana - onse morphological ndi structural (loukitsa majini). Mu thupi wamkazi limapangidwa awiri gonosom awiri X DNA (XX-awiri), ndipo mwamuna - X- wina ndi Y-khromozomu (XY-awiri).

Morphologically, asintha DNA pa selo magawano, iwo kawiri (kupatulapo nyongolosi maselo amene anawaonjezera kuwirikiza kawiri zimachitika). Izi akubwerezedwa nthawi zambiri, koma kusintha akonzedwa kuti asakhale ndi vutoli si anati. Kuti asakhale ndi vutoli kwambiri noticeable pa limodzi la magawo kuimira maselo (metaphase). Mu gawo ili DNA ndi umaimiridwa ndi awiri formations longitudinally unagawanika (mlongo chromatids) ndi mwapang'ono ndi amaphatikiza otchedwa constriction yaikulu kapena tsenromery (a chinthu chofunika wa khromozomu a). Otchedwa telomeres wa malekezero khromozomu. Kandalama khromozomu munthu anapereka DNA (deoxyribonucleic acid), imene encodes majini m'gulu zikuchokera awo. Chibadwa, nayenso mfundo za chizindikiro iliyonse.

Ndi angati DNA munthu kudzadalira kukula payekha. Pali zinthu monga aneuploidy (kusintha topangira DNA payekha) ndi polyploidy (nambala kukukhala haploid kuposa diploid). Yotsirizira ndi a mitundu yosiyanasiyana: imfa DNA magazi (monosomy) kapena maonekedwe a DNA owonjezera (trisomy - inayo, tetrasomiya - awiri owonjezera, etc.). Zonsezi chotsatira cha kutengera mapangidwe ndi chromosomal masinthidwe, tingayambe zinthu pathological monga: ozerezeka, syndrome Klinefelter, Turner Shereshevkogo ndi matenda ena.

Choncho, koma mzaka zana makumi awiri ankayankha mafunso onse, ndipo tsopano mmene DNA ambiri munthu amadziwa aliyense wokhala ophunzira a dziko lapansi. Ndi pa kodi zikuchokera kwa awiriawiri 23 DNA (XX kapena XY), izo zimatengera pa kugonana mwana, ndipo anatsimikiza pa umuna, ndi confluence a maselo amuna ndi akazi kugonana.