Q. No.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
1. Chromosomal aberrations
2. Genetic drift
3. Recombination
4. Transduction
Alleles are :
1. true breeding homozygotes
2. different molecular forms of a gene
3. heterozygotes
4. different phenotype
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 his classic experiments on pea plants, Mendel did not use
1. Pod length
2. Seed shape
3. Flower position
4. Seed colour
Which one of the following is not applicable to RNA?
1. 5’ phosphoryl and 3’ hydroxyl ends
2. Heterocyclic nitrogenous bases
3. Chargaff’s rule
4. Complementary base pairing
A pleiotropic gene:
1. is a gene evolved during Pliocene.
2. controls a trait only in combination with another gene
3. controls multiple traits in an individual.
4. is expressed only in primitive plants
A gene showing codominance has:
| 1. | alleles tightly linked on the same chromosome |
| 2. | alleles that are recessive to each other |
| 3. | both alleles independently expressed in the heterozygote |
| 4. | one allele dominant on the other |
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.
Which of the following most appropriately describes haemophilia?
| 1. | Dominant gene disorder |
| 2. | Recessive gene disorder |
| 3. | X-linked recessive gene disorder |
| 4. | Chromosomal disorder |
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