Question

3. A diploid organism is heterozygous for 4 loci, how many types of g
(c) Mond
can be produced?
4. Explain the Law of Dominance using a monohybrid cross.
5. Define and design a test-cross.
6. Using a Punnett Square, workout the distribution of phenotypic feat
in the first filial generation after a cross between a homozygous fer
and a heterozygous male for a single locus.​

Answer 1

Answer:

3. Types of gametes produced by organism= 2n wherein n= number of loci for which the organism is heterozygous. The given diploid organism is heterozygous for 4 loci, types of gametes produced = 24= 16.

4. Law of dominance explains that in a monohybrid cross between a pair of contrasting traits, only one parental character will be expressed in the F1 generation and both parental characters will be expressed in the F2 generation in the ratio 3:1.

5. A test cross is performed to determine the genotype of a dominant parent if it is a heterozygous or homozygous dominant. On the basis of the results obtained in the ratio of the offspring, it can be predicted that the parent is having which genotype.

6. It is quite clear that it is a test cross of a heterozygous male with a homozygous female. In the F1 generation following phenotypic feature are observed:

Half of the progeny are Heterozygous Tall (Tt)

Another half of the population is Homozygous short (tt)

Hence the ratio for phenotypic features is same as genotype ratio, which is 2:2 or 1:1.