Genetikadan masala ishlash

Diduragay chatishtirish.

Har ikki belgi bo‘yicha to‘liq dominantlik holatida belgilarning irsiylanishi.

49-masala. Quyidagi genotipga ega bo‘lgan organizmlar qanday tipdagi gametalarni hosil qiladi?

a) CCDD b) CcDD v) Ccdd g) CcDd d) ccdd

50-masala*. No‘xat o‘simligida donning sariq rangli bo‘lishini dominant A geni, yashil rangli bo‘lishini retsessiv a geni, donning silliq shaklda bo‘lishini dominant B geni va donning burishgan bo‘lishini retsessiv b geni belgilaydi. Quyidagi genotipga ega bo‘lgan no‘xat o‘simliklarini chatishtirishdan olingan keyingi avlod o‘simliklarning genotipini va fenotipini aniqlang.

1) AABB x aabb 2) AABb x aabb 3) AaBB x aabb

4) AaBb x aabb 5) AaBb x AaBb

Masalaning echilishi:

1) P ♀ AABB X ♂ aabb 2) P ♀ AABb X ♂ aabb

g AB ab g AB, Ab ab

F₁ AaBb - sariq, silliq F₁ AaBb - sariq, silliq

Aabb - sariq, burishgan

3) P ♀ AaBB X ♂ aabb 4) P ♀ AaBb X ♂ aabb

g AB, aB ab g AB, Ab, aB, ab ab

F₁ AaBb - sariq, silliq F₁ AaBb - sariq, silliq

aaBb - yashil, silliq Aabb - sariq, burishgan

aaBb - yashil, silliq

aabb - yashil, burishgan

5) P ♀ AaBb X ♂ AaBb

g AB, Ab, aB, ab AB, Ab, aB, ab

F₁

♂ ♀	AB	Ab	aB	Ab
AB	AABB s.s. 1	AABb s.s. 2	AaBB s.s. 3	AaBb s.s. 4
Ab	AABb s.s. 2	AAbb s.b. 5	AaBb s.s. 4	Aabb s.b. 6
aB	AaBB s.s. 3	AaBb s.s. 4	aaBB ya.s. 7	aaBb ya.s. 8
ab	AaBb s.s. 4	Aabb s.b. 6	aaBb ya.s. 8	aabb ya.b. 9

F₁ da olingan genotipik F₁ da olingan fenotipik Fenotipik

sinflar sinflar sinflar

nisbati

1 . AABB = 1 sariq, silliq (s.s.)

2. AABb = 2 sariq, silliq (s.s.) s.s. AˍBˍ = 9

3. AaBB = 2 sariq, silliq (s.s.)

4. AaBb = 4 sariq, silliq (s.s.)

5 . AAbb = 1 sariq, burishgan (s.b.) s.b. Aˍbb = 3

6. Aabb = 2 sariq, burishgan (s.b.)

7 . aaBB = 1 yashil, silliq (ya.s.) ya.s. aaBˍ = 3

8. aaBb = 2 yashil, silliq (ya.s.)

9 . aabb = 1 yashil, burishgan (ya.b.) ya.b. aabb = 1

Genotipik sinflar nisbati 1 : 2 : 2 : 4 : 1 : 2 : 1 : 2 : 1

Fenotipik sinflar nisbati 9 : 3 : 3 : 1