GENETICS PROBLEMS

GENETICS PROBLEMS

1. The mating of a red fruit bearing tomato plant with yellow fruit bearing plants yield 173

plants. Out of these, 84 bore red fruits, while 89 bore yellow fruits. The genotype of

the parents are most likely

a. RR,rr b. RR,Rr c. Rr,rr d. rr.rr

2. A man homozygous for brown colour marries a women heterozygous for brown colour. If the

gene for brown colour is dominant, what would be the expected fate of the children?

a. 1 brown b. 2 brown : 2 black c. 3 brown : 1black d. All brown

3. How many types of gametes can be produced by a genotype AABbCCDb?

a. 3 b. 4 c. 12 d. 27

4. A child receives-

a. 25% genes from its Father b. 50% genes from its father

c. 75% genes from its father d. 100% genes from its father

5. In a number of crosses made between two plants of genotypes. Tt and tt, about 1000

off springs are obtained, which of the following is the most likely distribution of the

off springs

a. 248 tt : 752Tt b. 748Tt : 252 tt c. 240 TT : 520Tt: 240tt d. 482 Tt:518tt.

6. To get the F2 genotype of a cross DDGGww X ddggww we shall require

a. 64 squires by checker board b. 32 squires by checker board

c. 16squires by checker board d. 8 squires by checker board

7. A purple flowered plant is crossed with yellow flowered plant. F1 hybrid obtained is yellow

flowered plant. if this yellow F1 hybrids is crossed with purple flowered plant, what

percentage of off springs is expected to have purple flowered approximately?

a. 25% b. 75% c. 50% d. 100%

8. If a plant carrying only black flower colour genes is crossed with a plant with only white

coloured genes, all the off springs have gray colour. If two of these are crossed,

the theoretical progeny ration would be

a. All Grey b. All back or white c. 1/2 black, 1/2white d. 1.2 grey, 1/4

white, 1/4 black

9. Let genes A and B both be necessary for normal hearing what is the possible genotype of

normal children of a deaf mother and deaf father?

a. Aabb b. aaBB c. AaBb d. aabb

10. In maize coloured endosperm (c) is dominant over colourless (c) and swollen or full

endosperm (R) is dominant over shrunken(r) when a dihybrid of F1 generation was

test crossed, it produced four phenotypes in the following percentage-Coloured full

. ............45% Coloured Shrunken ..........5% colourless full..........5% Colourless

shrunken..........45% From this data what would be the distance between the two

non-allelic genes?

a. 48 units b. 10 units c. 7 units d. 12 units

11. The test cross of an F1 individual with genotype (++/ab) produced the following off springs.

++/ a. b.......10 b. ab/ab...........10 c. +a/ab...............40 d. +b/ab..........40. Based on

this data, perdict the configuration of F1 heterozygous-

a. C- is configuration b. Trans configuration c. Both a & b

d. None of the above

12. If the frequency of allele B in a population is 0.70, the frequency of allele b would be

a. 0.30 b. 0.35 c. 0.70 d. 0.45

13. If two genes ‘a’ and ‘b’ are linked and show 20% recombination the proportion of gametes

produces in F1 by a dihybrid ++/ab derived from a cross between ++/++ and ab/ab

would be

a. ++ 80:ab 20 b. ++ 50:ab50 c. ++40: ab 40:+a 10: +b 10

d. ++ 20: ab 20: +a 20: +b 20

14. In man brown eyes (B) are dominant over blue (b) and dark hair (D) dominant over red(d).

A man with brown eyes and red hairs marries a woman with blue eyes and dark hairs

They got two children; one resembling the man the other the woman. The genotypes of

man and woman were

a. BBdd,bbDD b. Bbdd,bbDd c. BBdd,bb,Dd d. Bbdd, bbDD

15. O blood group offspring can never happen when -

a. Father is A and mother is B b. Father is O and mother is O

c. Father is O and mother is A,B d. None of the above answers.


ANSWERS

1.c 2.d 3.b 4.b 5.d 6.c 7.c 8.d 9.c 10.b 11.a&b 12.a 13.d&c 14.b 15.c