Which is the most common mechanism of genetic variation in the population of a sexually-reproducing organism?
1. Chromosomal aberrations
2. Genetic drift
3. Recombination
4. Transduction

An abnormal human baby with 'XXX' sex chromosomes was born due to :
1. formation of abnormal ova in the mother
2. fusion of two ova and one sperm
3. fusion of two sperms and one ovum
4. formation of abnormal sperms in the father

In a testcross involving F₁ dihybrid flies, more parental-type offspring were produced than the recombinant type offspring. This indicates:
1. Both of the characters are controlled by more than one gene.
2. The two genes are located on two different chromosomes.
3. Chromosomes failed to separate during meiosis.
4. The two genes are linked and present on the same chromosome.

The mechanism that causes a gene to move from one linkage group to another is called
1. Crossing-over
2. inversion
3. duplication
4. translocation

The genotypes of a Husband and Wife are IAIB and IAi .
Among the blood types of their children how many different genotypes and phenotypes are possible
1. 3 genotypes ; 3 phenotypes
2. 3 genotypes; 4 phenotypes
3. 4 genotypes ; 3 Phenotypes
4. 4 genotypes ; 4 phenotypes

An exchange of segments between non-homologous chromosomes is called as:
1. Crossing over

2. Inversion

3. Reciprocal translocation

4. Transposing

The gene for the enzyme Phenylalanine hydroxylase is located on chromosome:

1. 7
2. 11
3. 12
4. X

Mating between black rats of identical genotype produced offspring as follows: 14 cream colored, 47 black and 19 albino. This ratio can be explained if the pheneomenon exhibited here is:

1. Recessive epistasis
2. Polygenic inheritance
3. Multiple allelism
4. Incomplete penetrance

Identify the incorrect statement regarding test cross?

1. It is used to determine the genotype of an individual exhibiting a dominant phenotype.

2. The testcross parent is always homozygous recessive for all of the genes under consideration.

3. The purpose of the testcross is to discover how many different kinds of gametes are being produced by the individual whose genotype is in question.

4. A homozygous dominant individual will produce two types of progeny and a heterozygous individual will produce only one type of progeny.

What is the number of linkage groups in humans?

1. 22
2. 23
3. 24
4. 46