MUTATSIYA

MUTATSIYA (lot. Mutatio – tagyiryobi), tagyiryobii homilini akhbori irsii organizm, ki ba rekombinatsiyai genho vobastagi nadorad. Tamomi nabototu hayvonot ba M. qobiland. Tagyiroti nogahonii irsie, ki boisi paydoishi organizmhoi doroi khislathoi nav megardand, kayho boz malumand. CHunonchi, tagyiri shakl yo rangi bargu mevai nabotot, paydo shudani bolhoi ilovagi dar hasharot va g. hodisai muqarrarist. Tahqiqi ilmii M. dar a. 20 ba tufayli kashf shudani mekhanizmhoi asosii intiqoli akhbori irsi (nig. Irsiyat), tadqiqoti sokht va vazifai gen muyassar gasht.
Se navi M. – geni, khromosomi va genomi mavjud ast. M.-i geni tagyiryobii sokhti yagon gen meboshad. Dar in hol dar molekulai kislotai dezoksiribonukleat (KDN), ki mabdai sokhti gen meboshad (nig. Kislotahoi nukleat), juzhoi judogona (nukleotidho) mumkin ast ivaz shavand; az molekulai KDN qismathoi daroztar barham mekhurand yo baraks, ba on juzhoi ilovagi hamroh meshavand.
M.-hoi khromosomi tagyiryobii gunoguni sokhti khromosomaho, yane tashkilihoi takhsisyoftai homilini molekulahoi KDN-i yadroi hujayra meboshand. Hromosomaho mumkin ast komilan va qisman duchand shavand, qitahoi judogonai kheshro talaf dihand; yak qismi khromosoma ba 180° vojgun shavad yo dar digar joi hamon khromosoma joy girad va g.
Tagyiroti adadi umumii khromosomahoro M.-hoi genomi menomand. Dar in hol mumkin ast miqdori umumii khromosomahoi dasta ba tariqi karati (duchand, sechand va g.) ziyod shavad, khromosomahoi judogona talaf yoband yo baraks, khromosomahoi barziyod ba vujud oyand.
Tagyiroti nishonahoi irsii organizm, ki dar natijai M. rukh medihad, gunogun meshavad. Agar M. qitahoi duyumdarajai sokhti irsiro darbar girifta boshad, on goh tabadduloti ruydoda ba faoliyati hayotii organizm chandon tasir nameguzorad va M. noayon memonad. Dar baze mavridho M. vazifai organizmro khalaldor nakunad ham, khususiyathoi irsii onro ba tavri nazarras digargun mesozad (mas., digargun shudani rangi pashmi nasli hayvonot va g.). Bilokhir dar natijai M. mumkin ast faoliyati hayoti ba tavri jiddi khalal yofta, hatto organizm barmahal halok gardad. CHunin M.-ho yak qator bemorihoi inson, ba istiloh bemorihoi irsiro ba vujud meorand.
Dar baze mavridho M. sifati mutobiqsozandai nofe dorad (mas., tagyir yofta ba rangi nabotot monand shudani rangi hasharot).
Zuhuroti M. ba hujayrai mutahavvil vobasta ast. M. dar hujayrahoi janini (baroi inson – tukhmhujayra yo nutfa) boisi rushdi organizmi komilan mutagayir gardida, az nasl ba nasl meguzarad. M.-hoi digar hujayraho (ba istilohi M.-hoi badani) vobasta ba marhalai inkishofi organizm, ki dar on M. surat giriftaast, yak qismi muayyani badanro faro megirand. Dar natijai M.-i badani, mas., dar inabiyai chashm kholhoi rangorang, dar pust doghoi safedi bepigment va g. padid meoyand. M.-hoi badani az nasl ba nasl nameguzarand.
M.-hoe, ki biduni tasiri yagon omili beruni dar sharoiti muqarrarii hayoti organizmho ba vujud meoyand, «khudrusta» nom dorand. In qabil M.-ho nihoyat kam vomekhurand (mas., dar hujayrahoi janini inson bo basomadi 1:100000).
Soli 1925 ba olimoni shuravi G. A. Nadson va G. S. Filippov ba tavri suni ziyod kardani basomadi M. muyassar gardid. YAk qator omilhoe, ki bunyodi fiziki, khimiyavi yo biologi dorand, yane mutagenho M.-ro ba vujud ovarda metavonand. Samarai mutagen ba miqdor, davomiyati tasiri on va khususiyathoi organizm vobasta ast. Hama navhoi nurafkanii ionho, afkanishoti ultrabunafsh, bisyor payvasthoi khimiyavi va baze virusho va doruho khosiyati mutageni zohir menamoyand. CHandin alkaloidi naboti, baze antibiotikho, sulfanilamidho va moddahoi gandzudoy mutagenhoi qavi ba shumor meravand. Ba baze mahsuli metabolizmi hujayra (pereoksidho, radikalhoi ozod va g.) niz faolii mutageni khos ast. Basomadi M.-hoi inson va hayvonro mavjudoti tufaylie, ki dar badani onho zindagi mekunand, metavonand tagyir dihand.
Masalai mutagenez (rushdi M.) vaqthoi okhir ba munosibati iflosii muhiti zist ahamiyati khosa paydo kard. Tamarkuzi miyonai mutagenho, ki imruz dar muhiti zist muayyan karda meshavad, ba jonvaroni ozmuni tasiri manfi namerasonad. Vale boyad dar nazar dosht, ki omilhoi gunoguni iflossozandai muhiti zist ba yakdigar tasiri mutaqobila rasonda, tahavvuloti murakkabi khimiyavi va biologiro az sar meguzaronand va dar nihoyati kor komplekshoi faoli mutageni hosil mekunand.
Osebi molekulai KDN hatman boisi M. nagardida, mumkin ast ba tufayli sistemahoi muassire, ki dar hujayra vujud dorandu osebhoi genetikiro bartaraf mesozand, beasar az bayn ravad. Zuhuroti geni mutanti mumkin az tasiri geni digar furu nishinad. Dar in mavrid geni mutanti az nasl banasl meguzarad va faqat dar surate padid meoyad, ki dar hujayrai janin du geni mutantii yakson bo yakdigar duchor shavand. Barkhe az M.-ho faqat dar sharoiti muayyani zindagi (mas., dar harorati muayyani parvarishi mikroorganizmhoi mutanti) zohir meshavand.
Qobiliyati mutatsioni (tagyirdihi)-i genho zeri nazorati genetiki ast. Dar dastai umumii genho genhoe yoft shudaand, ki ba faolii fermentho asar karda, basomadi tahavvuli genhoi judogona yo kulli genhoro digargun mesozand. CHande az onho basomadi tahavvulro ziyod, digarhoyashon kam mekunand. Agar baloravii basomadi tahavvul boisi afzudani digargunihoi baroi organizm nomatlub gardad, pas kamshavii tagyirot baroi tamomi namudi mazkur sozgor nameboshad, zero imkoniyathoi mutobiqatii onro mahdud mesozad.

R. A. Rahmonov.