MEYOZ

MEYOZ (az yun. meiosis — kamshavi), taqsimshavii takhfifi, yake az tiphoi mitoz, ki dar natijai on miqdori diploidii khromosomaho to miqdori gaploidi kam meshavand. Meyoz dar naslhoi oyanda bozdorii majmui diploi­dii khromosoma­ho va kombinasiyai navi informasiyai irsiro tamin mekunad. Meyozi hayvonotro olimi nemis O. Gertvig (1890), Meyozi rastanihoro tadqiqotchii rus V. I.

Belyaev (1892) kashf kardaast.

Meyoz dar natijai du karat taqsimshavii yadro, ki har yaki on az 4 fa­za iborat ast, ba vujud meoyad. Duchandshavii shumorai khromosomaho faqat yak marotiba ba vuqu meoyad, binobar in 4 hujayra bo majmui gaploidii khromosomaho hosil meshavad. Dar profazai taqsimshavii yakum spiralizasiya va konkgasiya (juftshavi)-i khromosomahoi gomologii duchandshuda ba amal meo­yad; dar bayni khromosomaho krossingover imkonpazir ast. Dar metafaza khromosomahoi gomologii juftshuda dar ekvatori hujayra joygir shuda, torhoi duki akhromatini ba on payvast meshavand. Dar anafaza jufti khromosomahoi konyugasiyashuda sui qutbho harakat mekunand; dar on jo miqdori khromosomaho duchand kam, lekin har yak khromosoma az du khromatida (nimai khromosomaho) iborat ast. Badi telofazaya kutoh (hangomi on dar har yak qutb despiralizasiyai khromosomaho va hosilshavii yadroyu hujayrahoi nav ba vujud meo­yad) taqsimshavii digar cap meshavad.