F₂ generation in a Mendelian cross showed that both genotypic and phenotypic ratios are same as 1 : 2 : 1 It represents a case of :
1. Co-dominance
2. Dihybrid cross
3. Monohybrid cross with complete dominance
4. Monohybrid cross with incomplete dominance

If both parents are carrier for thalessemia, which is an autosomal recessive disorder, what are the chances of pregnancy resulting in an affected child ?
1. 50%
2. 25 %
3. 100%
4. no chance

Which of the following statements is not true of two genes that show 50% recombination frequency?
1. The genes are tightly linked
2. The genes show independent assortment
3. If the genes are present on the same chromosome, they undergo more than one crossovers in every meiosis
4.The genes may be on different chromosomes

Fruit colour in squash is an example of :
1. Recessive epistasis
2. Dominant epistasis
3. Complementary genes
4. Inhibitory genes

Person with blood group AB is considered as universal recipient because he has:
1.both A and B antigens on RBC but no antibodies in the plasma.
2. both A and B antibodies in the plasma.
3. no antigen on RBC and no antibody in the plasma
4. both A and B antigens in the plasma but no antibodies

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