Which of the following conditions represents a case of co-dominance genes?

(1) A gene expresses itself, suppressing the phenotypic effect of its alleles. 

(2) Genes that are similar in phenotypic effect when present separately, but when together interact to produce a different trait.

(3) Alleles, both of which interact to produce a  trait, which may or may not resemble either of the parental types.

(4) Alleles, each of which produces an independent effect in a heterozygous condition. 

Which of the following is correct ?

(1) Henking discovered the small Y-chromosome.

(2) Drosophila also shows XX-XY sex determination like human.

(3) Birds have ZZ-ZW sex determination, where females are ZZ and males are ZW.

(4) Grasshoppers show XX-XY sex determination. 

Which of the following is true for a recessive disease in family A and B?

(1) In family A, both the parents are homozygous recessive.

(2) In family B, both the parents are homozygous dominant.

(3) In family B, both the parents are heterozygous recessive.

(4) In family A, both the parents are heterozygous recessive. 

Which of the following occurs due to monosomy of sex chromosome?

1. Down's syndrome

2. Turner's syndrome

3. Haemophilia

4. Sickle cell anaemia

In rabbits, the gene for grey fur (G) is dominant over that for black fur (g). In a litter, if 50% rabbits are grey, then the possible parental cross combination is 

(1) GG X Gg

(2) GG X GG

(3) gg X gg

(4) Gg X gg.

Barr Body is found in the cytoplasm during 

(1) interphase in cell of female mammal

(2) interphase in cell of male mammal

(3) prophase in cell of female mammal

(4) prophase in cell of male mammal.

If both parents are carriers for thalassaemia, which is an autosomal recessive disorder, what are the chances of pregnancy resulting in an affected child?

(1) 25%

(2) 100%

(3) No chance

(4) 50%

If 'A' represents the dominant gene and 'a' represents its recessive allele, which of the following would be the most likely result in the first generation offspring when Aa is crossed with aa ?

1. All will exhibit dominant phenotype.

2. All will exhibit recessive phenotype. 

3. Dominant and recessive phenotypes will be 50% each.

4. Dominant phenotype will be 75%.

In a pea plants, green pod colour is dominant over yellow pods. 1000 seeds taken from a pea plant on germination produces 760 green pod and 240 yellow pod plants. The parental genotype and phenotype of the seed plant are 

(1) Heterozygous and yellow

(2) heterozygous and green

(3) homozygous and yellow

(4) homozygous and green

A colourblind man marry with a daughter of colourblind father, the generation will be 

(1) there will be no daughter colourblind

(2) all sons will be colourblind

(3) all daughter will be colourblind

(4) half sons will be colourblind