MAFHUMHOI ASOSII GENETIKI

Genetika du khususiyati asosii organizmhoi zinda – irsiyat va tagyirpaziriro meomuzad. Irsiyat hamchun khususiyati az nasl ba nasl guzaronidani alomatho, khosiyathoi irsi va asosi inkishofro dar bar megirad. Bo sharofati irsiyat dar tabiat har yak namudi rastani va hayvon khususiyathoi khosi khudro dar muddati muayyani tarikhi nigoh medorad. Jihati digari irsiyat nigoh doshtani inkishofi muayyani har fard va namud, makhsusiyati mubodilai moddaho va takroryobii fardi meboshad.

Barqarorshavi ba vositai hujayra guzashta, on dar natijai makhsusgardoni ba hujayrahoi jinsi va gayrijinsi (badan) judo meshavand. Dar in hujayraho nafaqat alomatho, balki hissachahoi makhsus, ki onhoro gen menomand, ba meros meguzarand. Gen hissachai irsi buda (yak qismi molekula KDN yo khromosoma), inkishofi alomatho yo sintezi molekulahoi safedahoro idora mekunad.

Genho metavonand alomatro zohir namoyand va yo baraks, paydo nakunand. Zohirshavii alomat ham ba gen, ham ba muhiti zist va ham ba tasiri digar genho vobasta ast. Genho dar khromosomaho joy doshta, har yak gen dar khromosomahoi gomologi joyhoi ba ham monandro sohiband. Dar dastai khromosomahoi gaploidi (toq)-i prokariotho yo hujayrahoi jinsii eukariotho az har yak gen tanho yaktoi joygir ast. Dar dastai khromosomahoi diploidi (juft)-i hujayrahoi badani eukarioti jufti khromosomahoi gomologi va du alleli genidida meshavad, ki in yo on alomatro nazorat mekunand.

Genhoe, ki dar joyhoi ba ham monandi khromosomahoi gomologi joygirand, genhoi alleli (az kalimai yunoni alle1a ba ham monand) nom dorand. Genhoro bo harfho ishora mekunand, Genhoi alleli, ki paydarhamii nukleotidhoyashon yakkhelaand, chunin navishta msshavand – AA.

Dar natijai mutatsiya ivazshavii nukleotidhoi molekulai KDN ba amal meoyad, ki boisi ivaz shudani alomatho megardad. Genho metavonand chand marotiba ba mutatsiya duchor gardand va dar natija silsilai allelhoi genro ba vujud ovarand.

In hodisaro seralleli yo silsilai serallelizm menomand. Majmui genhoi yak fard genotip nom dorad. Zohirshavii genotip ba muhiti zisti fardho va bo ham aloqamandii genho vobastagi dorad. Genho ba hamdigar tasir rasonda, muhiti genotipro hosil mekunand. Ba iborai genetiki mashhur M.E.Lobashev, genotip in sistemai bo ham tasir rasonii genhost. Dar doirai yak namud fardhoi gunogun ba ham monand nestand, ki in natijai tagyirpazirist. CHunin tagyirpazirii fardro dar misoli odam va namudhoi rastani va hayvonot didan mumkin ast.

Hamin tariq, tagyirpaziri khilofi irsiyat buda, peshrafti biologiro tashkil mekunad. Tagyirpaziri – tagyir yoftani hissachahoi irsi, yane genho buda, dar natijai in alomatho va khususiyathoi organizmho digargun meshavand. SHakl va sababhoi tagyirpaziri gunogun ast va baroi tahavvulot (evolyutsiya) ahamiyati makhsus dorad, ki inro fanni genetika meomuzad. Dar rafti omuzishi qonuniyathoi merosguzorii alomathoi irsii organizmho tadqiqotchiyon, asosan, bo natijai mahsuli tabdilyobii genho, yane alomatho, saru kor dorand.

Majmui alomathoi organizmro fenotip menomand. Albatta, fenotip nafaqat alomathoi ba chashm namoyon (rangi chashm, muy, shakli gush, bini yo rangi gulho va gayra), balki alomathoi nonamoyon (shakli molekulaho, sokhtori safeda yo fermentho, konsentratsiyai glyukoza va yo durdai peshob dar khun, shakl va andozai hujayraho, sokhti boftaho va uzvho, sokhti badan va bo ham aloqamandii joygirshavii uzvho)-ro dar bar megirad. Ba iborai digar, mafhumi alomat ba gayr az paydarhamii nukleotidhoi KDN khususiyathoi sokhti organizmro dar zinai inkishof tashkil menamoyad. Iborai khosiyat boshad, khususiyathoi funksionalii organizm buda, asosi onro sokhti alomatho yo guruhi alomathoi oddi tashkil mekunand.

Aksari alomathoi oddii ba chashm namoyon hamchun fahmishi shartii farqkunanda khosi organizmho buda, dar asl bo ravandhoi serzinai murakkabi biokhimiyavi (safeda-fer-ment-alomat) vobastaand.

Hullas, genetika ilm dar borai qonuniyathoi irsiyat va tagyirpaziri buda, guyo khilofi yakdigarand. Ammo dar asl onho ba hamdigar aloqai zich dorand. In khususiyatho baroi hamai makhluqhoi zindai rui Zamin khosand.

Savolho baroi sanjish:

1. CHiro irsiyat menomand? Gen chist?
2. Genhoi alleli dar natijai kadom hodisa ba amal meoyand?
3. Serallelizm chist?
4. Qoidai mafhumi tagyirpaziriro sharh dihed.
5. Qoidai mafhumi genotip va fenotipro sharh dihed.

 Istilohot:

1. Tagyirpaziri – qobiliyati alomatho va khosiyathoi nav paydo namudani organizmhoi zinda.
2. Alomat – khosiyati sokhtori organizmho dar darajai molekulavi, sitologi, gistologi va anatomi.
3. Genotip – jami tasiri tarafayni genhoi organizm.
4. Fenotip – majmui hamai alomatho va khosiyathoi organizm.
5. Hosiyat – har yak khosiyati funksionali, ki asosi onro yak yo chand alomat tashkil mekunad.
6. Gen – porchai molekulai KDN yo khromosoma, ki inkishofi alomathoi muayyanro ba vujud meorad.
7. Irsiyat – khosiyati organizmhoi zinda, ki alomatho va khususiyathoi inkishofi khudro ba naslho meguzaronad.