A man with blood group ‘A’ marries a woman with blood group ‘B’. If their child has blood group ‘O’ then what could be their genotype?

1. Both are homozygous

2. Man is homozygous while woman is heterozygous

3. Both are heterozygous

4. Man is heterozygous while woman is homozygous

If two persons 'AB' blood group marry and have sufficiently large number of children, these children could be classified as 'A' blood group : 'AB' blood group : 'B' blood group in 1 : 2 : 1 ratio. Modern technique of protein electrophoresis reveals presence of both 'A' and 'B' type proteins in 'AB' blood group individuals. This is an example of

(1) codominance

(2) incomplete dominance

(3) partial dominance

(4) complete dominance 

ABO blood groups in humans are controlled by the gene I. It has three alleles — I^A, I^B and i. Since there are three different alleles, six different genotypes are possible. How many phenotypes can occur?

(1) Three

(2) One

(3) Four

(4) Two

To study whether a gene exhibits multiple allelism or not one must study:
1. An individual
2. A population
3. A species
4. With concentration

In case of starch synthesis in pea seeds [controlled by B gene], BB homozygotes produce large and round starch grains; bb homozygotes produce smaller and wrinkled starch grains and Heterozygotes produce round seeds of intermediate size. What can be inferred from this observation?

(1) The gene B mutates at a faster rate.

(2) The gene B is easily influenced by the environment

(3) Dominance is not an autonomous feature of a gene or the product that it has information for

(4) Some genes do not follow the law of segregation.

What can be the blood groups of progeny whose father and mother are of AB and O blood group respectively?
1. A and B only

2. AB only

3. All except O

4. A, B, AB and O

In a marriage between a male with blood group A and a female with blood group B, the progeny had either blood group AB or B. What could be the possible genotype of the parents?

1. I^A i (Male) ; I^B I^B (Female)

2. I^A I^A (Male) ; I^B I^B (Female)

3. I^A I^A (Male) ; I^B i (Female)

4. I^A i (Male) ; I^B i(Female)

The phenotype of an individual may be affected if the modified allele produces

A.  The normal/less efficient enzyme

B.  No enzyme at all

C.  A non-functional enzyme

1.  Only A is correct 

2.  Only C & A are correct

3.  Only B is correct

4.  B & C are correct 

ABO blood groups are controlled by which gene

(1) a

(2) I

(3) b

(4) All of the above

In ABO blood grouping how many genotypes show co-dominance? 

(1) 1

(2) 2

(3) 3

(4) 4