GENOTIP HAMCHUN SISTEMAI TOM

Genho asosi strukturi va funksionalii hissai irsiyatro tashkil mekunand. Az misolhoi dar bolo zikrshuda malum gardid, ki genho hissachai alohida buda, har yak az onho yagon alomatro muayyan mekunad va ba hamdigar vobastagi nadorand.

Az in lihoz, chunin fikr ba miyon omadanash mumkin ast, ki guyo genotip majmui mekhaniki (bealoqamandi)-i genho va fenotip shakli omekhtai alomathoi alohida boshad. Dar asl chunin nest. Albatta, hujayrai alohida va organizm siste-

mai tom (purra)-ro tashkil karda, dar organizm hamai ravandhoi biokhimiyavi va fiziologi ba ham aloqai zich dorand va muvofiqand, zero hamai in bo genotip, yane ba sistemai bo ham aloqamandi genho vobasta ast. Tasiri tarafayn ham dar allelhoi yak gen va ham dar genhoi gayrialleli, ki dar joyhoi yakkhela (lokus)-i yak khromosoma yo khromosomahoi gunogun voqe gashtaand, ba amal meoyad.

Tasiri baynihamii genhoi alleli

Genhoi alleli nisbati yakdigar dar shakli dominanti va resessivi zohir megardand. Dominant purra va nopurra meshavad. Inchunin dar bayni genhoi alleli shaklhoi digari aloqai tarafayn vomekhurand. YAke az inho hodisai ko-

dominanti (du geni alleli alomatro barobar zohir meku nand) ast, ki dar merosguzorii guruhi khuni odam, sistemai AVO va MN dida meshavad. SHakli digari merosguzori az dominant baland meboshad. Masalan, darajai balandi zo-

hirshavii alomat dar organizmhoi geterozigoti namoyon megardad va in yake az sababhoi zuhuroti hodisai geterozis (purquvvatii nasli yakum) meboshad. Tasiri baynihamii genhoi gayrialleli

Bisyor misolho malumand, ki yak gen bo genhoi digari gayrialleli yo ba ehtimoliyati zohirshavii khudi gen tasir mekunad. Misoli tasiri tarafayni du jufti genho – in merosguzorii shakli toji baze murgon meboshad. Dar natijai omezish (kombinatsiya)-i gunoguni in genho chor shakli toj paydo meshavad (rasmi 9.6.).

Rasmi 9.6. SHaklhoi toji khurusho:

A – mukarrari (aavv),

B – nakhudmonand (aaVV yo aaVv),

V – chormagzmonand (AAVV yo AaVv),

G – gulmonand (AAvv yo Aavv)

Dar nakhudi khushbui geni A sintezkunandai moddai pigmenti berang ast (propigment). Geni V – sintezkunandai ferment, ki bo yorii on az propigment pigment sintez meshavad. Gulhoi nakhudi khushbuy genotipi aaVV va AAvv-dosh-

ta, rangashon safed ast. Dar genotipi yakum ferment vujud dorad, ammo moddai mahsuli pigment nest. Dar genotipi duyum mahsuli moddai pigment hast, vale ferment nest, ki pigment sintez shavad, baroi hamin gulhoi onho berangi

safedand. Az duraga kardani in du shakli nakhudi khushbuyi gulhoyashon safed, dar rastanihoi (G1) digeterozigoti ham mahsuli moddai pigmenti (A) va ham ferment (V) majud buda, dar paydo kardani pigmenti gulobi ishtirok dorand.

CHunin alomati oddii rangi gul dar natijai tasiri tarafayni jufti genhoi gayrialleli paydo shuda, mahsuli moddahoi onho yakdigarro purra megardonand. CHunin shakli tasiri baynihamii jufti genhoi gayrialleliro tasiri baynihamii komplemantari yo ilovagi menomand. Ba sifati misoli digar mo shakli tasiri tarafayni genhoro dar rangi muinai khukbachaho dida mebaroem, ki inro tasiri baynihamii epistazi menomand.

Az duraga kardani khukbachahoi siyoh va safed dar nasli yakum rangi safed paydo meshavad. Agar naslhoi yakumro bo ham duraga kunem, on goh dar nasli duyum (G2) chunin tanosubi fenotipi paydo meshavad: safedho – 12/16, siyohho – 3/16 va surkh-

ho – 1/16. Hamai khukbachahoi safed faqat yak geni dominantii pakhshkunanda J kalon dorand. Naslhoi siyoh boshand, bo genii (ii), ki bo paydo shudani rang dakholat namekunand, gomozigotiand va geni dominanti E dorand, ki rangi siyohro paydo mekunad. Hukchahoi surkh (ee ii) geni dominanti nadorand.

Hamin tariq, genhoe, ki bo geni digari gayrialleli tasir merasonand, genhoi pakhshkunanda (epistazi) nom dorand.

CHunin shakli tasiri baynihamii genhoi gayrialleli baroi alomathoi miqdori ham khos ast. Bisyor alomatu khosiyati organizmho, ba monandi vazn, inkishofi hayvonot, tukhm mondani murg, ravgannoki va miqdori shir, miqdori vitaminho dar rastani va gayra ba guruhi alomathoi miqdori dokhil meshavand. Onho az jonibi genhoi tasirashon yakkhela muayyan karda meshavand va ba yak alomat tasir merasonad, ki inro hodisai polimeri menomand.

CHi qadar dar genotip miqdori genhoi dominanti bisyor boshand, hamon qadar zohirshavii in yo on alomat afzun megardad va baraks. Rangi surkhi doni gandum bo du geni A1A2 vobasta ast. Dar ayni hol genhoi gayrialleli bo yak harf A(a) ishora shudaand, zero onho inkishofi yak alomatro nazorat mekunand.

Dar genotipi A1A1A2A2 rangi doni gandumi surkh az hama balandand, vale dar genotipi a1a1 a2a2 rangi donho safedand.

Vobasta ba miqdori genhoi dominanti dar genotip shaklhoi gunoguni rangro az surkhi baland (dar shakli guzasht) tosafed paydo kardan mumkin ast (rasmi 9.7).

Miqdori pigmenti rangi pusti odam ham ba miqdori genhoi gayriallelii tasirashon yakkhela vobasta ast. Tasiri baynihamii merosguzori bisyor alomathoi muhimi hayvonot va rastaniho, masalan, miqdori qandi bekhmeva, da-

rozii khushaho, darozii sutahoi juvorimakka, nasldihii hayvonho va gayra bo hamin roh meguzarand. Hamin tavr, bisyor alomatho bo rohi tasiri tarafayni chand jufti alomatho, yane polimerii yakkhela inkishof meyoband. Bazan holathoe vomekhurand, ki yak gen metavonad chand alomat va khosiyathoi organizmro nazorat kunad.

In hodisaro pleyotropi (az yunonii pleion – sermiqdor va tropos – taraf) menomand. Masalan, dar odam gene mavjud ast, ki yakbora ham nuqsoni nokhunho va ham kosachai zonuro nazorat mekunad. Dar mushho boshad, geni mutanti ast, ki zeri tasiri onho ustukhonho purra inkishof nameyoband.

Asosi tasiri genhoi pleyotropiro zohirshavii genho dar avval (ontogenez)-i inkishofi individuali tashkil mekunad. Hamin tariq, gen mafhumi sharti buda, muayyankunandai qismi alomathost, zero tasiri har gen bo geni digar, aniqtarash ba muhiti genotip vobasta ast.

Savolho baroi sanjish:

1. Kadom alomathoi nakhudi omukhtai G.Mendel bo rohi dominanti ba meros meguzarand?
2. Misolhoe ored, ki tasiri gen bo zohirshavii tasiri genhoi allelii digar aloqamand boshand.
3. Tasiri baynihamii genhoe, ki dar serallelizm dokhil meshavad, chi guna ast?
4. SHaklhoi tasiri baynihamii genhoi gayrialleliro sharh dihed.

Istilohot:

1. Epistazi – hodisae, ki yak gen imkon namedihad, ki digar geni gayrialleli ba kor daroyad.
2. Polimeri – hamroh tasir kardani yakchand jufti genhoi alleli, ki yak alomatro muayyan mekunand.
3. Pleyotropi – tasiri yak gen, ki chand alomatro nazorat mekunad.
4. Komplementari – ilova shudani yak gen bo zohirshavii alomathoi geni digari gayrialleli.
5. Kodominanti – hodisai yakjoyagi va purra zohirshavii du alleli gen dar holati geterozigoti.
6. Dominanti nopurra – shakli tasiri baynihamii genhoi alleli, ki geni dominanti geni resessiviro purra pakhsh namekunad.