GENETIKAI JINS. MEROSGUZORII ALOMATHOI BO JINS CHASPIDA

Masalai inkishof va paydoishi farqiyati jinsi, mekhanizmi muayyan kardani jins, nigoh doshtani tanosubi muayyani jinsi dar guruhhoi organizmi hayvon nafaqat ahamiyati nazariyavii biologi, balki ahamiyati amali niz dorad.

Alalkhusus, bo rohi suni tanzim kardani jins baroi kishovarzi manfiat meorad. Jins dar bisyor hayvonot dar ayyomi bordorshavi muayyan meshavad. Dar in surat mavqei asosii jihati genetikii muayyan kardani jins ba dastai khromosomahoi zigota vobasta ast. Medonem, ki dastai khromosomahoi zigota juft buda, onhoro khromosomahoi gomologi menomand. Hromosomahoi gomologi shakl, andoza va inchunin genhoi yakkhela dorand. Dar rasmi 5.16. dastai khromosomahoi odam, yane mardu zan aks yoftaast. Dar kariotipi zanhamai khromosomaho juftand, ammo dar kariotipi mard yak khromosomai nisbatan kalon, ki gomologi khudro nadorad, dida meshavad. Dar kariotipi mard inchunin khromosomaikhurdi chubchashakl, ki tanho ba mard khos ast, vomekhurad.

Hamin tariq, kariotipi odam 22 jufti khromosomai yakkhela dorad, ki bo onho mardu zan farq namekunand, vale bo yak jufti digari khromosoma hardu jins farq menamoyad. Hromo somahoero, ki dar hardu jins yakkhelaand, khromosomahoi autosomi menomand. Hromosomahoe, ki bo onho jinsi narina va modina az hamdigar farq mekunand, khromosomahoi jinsi yo geterokhromosoma nom dorand. Hromosomahoi jinsii zanona yakkhela buda, onhoro khromosomahoi X menomand. Dar mardho yak khromosomai H va yak khromosomai U mavjud ast. Dar vaqti afzoishi hujayrahoi jinsi dar natijai taqsimshavii meyozi gametahoi gaploidi paydo meshavand. Az jinsi modina tanho gametahoi doroi H-khromosoma ba vujud meoyand.

On jinsero, ki gametahoi yakkhelaro ba vujud meorad, jinsi gomogameti menomand (HH). Dar vaqti inkishofi gametahoi jinsii narina du navi gametaho paydo meshavand. YAne nisfi gametaho H-khromosoma va nisfi digarashon U-khromosoma dorand. Jinse, ki du khel gametahoi gunogunro paydo mekunad, jinsi geterogameti (XU) nom giriftaast. Dar odam, magasi drozofila va baze guruhhoi organizmhoi digar jinsi modina gomogametiand. Lekin dar shabparakho, khazan-

dagon va parrandagon narinaho gomogametiand.

Kariotipi khurus bo XX va mokiyon bo HU- ishora shudaast. Dar odam roli asosiro dar muayyan kardani jins U-khro-mosoma mebozad.

Agar dar vaqti bordorshavi hujayratukhm bo nutfai narinai H-khromosomador yakjoya shavad, on goh jinsi modina tavallud meshavad. Hamin tariq, zanho yak khromosomai H-ro az padar va yak khromosomai H-ro az modar giriftaand.

Agar hujayratukhm dar vaqti bordor shudan bo nutfai narinai U-khromosomador yakjoya shavad, on goh organizmi narina inkishof meyobad. Mard (HU) khromosomai H-ro tanho az modar megirad, ki in ba khususiyati merosguzorii genhoi

khromosomahoi jinsi vobasta ast. Merosguzorii alomathoyo genhoi onho dar khromosomahoi X yo U joygir buda, merosguzorii hampayvasti bo jins nomida meshavad.

Hamin tariq, genhoi bo jins chaspida manoi onro dorad, ki genhoyashon dar khromosomahoi jinsi joygirand. Taqsim gashtani in guna genho dar naslho ba raftori khromoso mahoi jinsi hangomi taqsimshavii meyozi va omezish (yakj-

oyashavi)-i onho dar bordorshavi vobasta ast. Merosguzorii genhoi dar H-khromosoma joygirshudaro dida mebaroem. Dar khotir boyad dosht, ki dar khromosomahoi jinsi genhoe ham hastand, ki dar paydoishi alomathoi jinsi ishtirok nadorand, masalan, dar X-khromosomai drozofila genimuayyankunandai chashmi surkh, dar X-khromosomai odam, genimuayyankunii lakhtshavii khun (N). Alleli resessivii in gen(h) boisi paydoishi bemorii vaznini gemofiliya gardidaast. Dar hamin khromosoma inchunin geni nobinoii rangi surkh va sabz (daltonik), shakl va andozai dandonho, sintezi baze fermentho va gayra joygirand.

Dar vaqti zuhuroti hampayvastii genho bo jins boshad, genhoi resessivii genotipho nisbat ba genhoe, ki dar khromosomahoi autosomi joygirand, dar holati tanhoi zohir meshavand. In guna genho dar hamon holat namoyon meshavand,

ki agar geni resessivi bo X- khromosoma chaspida, dar organizmi geterogameti joygir boshad. Dar kariotipi HU-doshta geni resessivi dar H-khromosoma buda, alomati khudro zohir mekunad, zero X va U khromosomaho bo ham gomolog nestand va dar U-khromosoma alleli geni dominanti pakhshkunanda dida nameshavad.

Merosguzorii geni ba jins chaspidai daltonizm dar naqshai zerin (dar naqsha khromosomahoi autosomi nishon doda nashudaand, chunki bo onho farqiyati organizmhoi narina va modina dida nameshavad) nishon doda shudaast:

Merosguzorii gemofiliya boshad, hangomi dorandai (baranda) geni in bemori budani zan va solim budani mard dar naqshai poyon ovarda shudaast:

N-geni solimi lakhtshavii khun, h- gemofil, 50%-i pi- sarho ba bemorii gemofiliya giriftorand. Gene, ki dar khromosomai U joy giriftaast, tanho az padar ba pisar meguzarad. Holo boshad, merosguzorii bisyor alomathoi mutadil va bemoriho dar odam omukhta shudaand.

Savolho baroi sanjish:

1. Kadom khromosomaro jinsi menomand?
2. Kadom jins gomogameti va kadom geterogameti nom dorad?
3. CHaspaki bo jins chi mano dorad? Misolho ored.
4. Baroi chi alomathoi geni resessivii dar H-khromosoma buda zohir meshavand?
5. Oid ba alomathoi dominanti va resessivii odam miso lho ored.

Istilohot:

1. Gametahoi chillikishuda – gametahoe, ki dar natijai chillikishavi paydo shudaand.
2. Hampayvasti bo jins – alomathoe, ki genhoyashon dar khromosomahoi jinsi joygirand, hampayvasti bo jins nom dorand.
3. Geterokhromosomaho – khromosomahoi jinsi, ki dar jinsho az yakdigar farq mekunand.
4. Guruhi hampayvasti – khromosomahoi gomologi, ki allelhoi genii onho guruhi chaspakiro tashkil mekunand. Miqdori guruhi chaspaki barobari miqdori khromosomahoi gaploidi ast.
5. CHaspakii genho – genhoe, ki dar yak khromosoma joygirand, genhoi chaspida nom dorand.