List of top Zoology Questions on Genetics

Sex determination in butterflies is:

If blood group of mother is B (homozygous) and that of father is A (homozygous), these blood groups are absent in their children.

Study the following and choose the correct statements.

• Cumulative effect of two or more genes on a single phenotypic trait is known as polygenic inheritance.
• Karyotype of Turner syndrome is AA+XXY.
• The longest gene codes for the muscle protein dystrophin.
• Highest number of genes are located in 21^st chromosome.

Trisomy of 23^rd chromosome in male results in

If the blood groups of parents are homozygous for A and homozygous for B blood groups, these blood groups are not expected in their children

‘O’ બ્લડ ગ્રુપવાળા વ્યક્તિ માટે, માતા-પિતાના બ્લડ ગ્રુપ જીનોટાઇપની નીચેની કઈ કોમ્બિનેશન શક્ય નથી?

For a person with blood group 'O', which of the following is not a possible combination of parents' blood group genotypes ?

Study the following and choose the correct statement: I. Sickle cell anemia is due to replacement of glutamic acid in 6th position by valine II. Thalassemia is sex linked disorder due to recessive genes III. Down syndrome is an allosomal disorder IV. Phenylketonuria is due to mutation of the gene-PAH in chromosome 12

If mother is carrier for haemophilia and father is normal, chance of their children to be haemophilic is:

Deficiency of the blood clotting factor VIII results in:

Match the following:

Assertion (A): The p53 gene is often called guardian angel of human genome. Reason (R): It inhibits the development of tumors.

Study the following statements regarding genic balance theory and identify incorrect statements: A) The production of gametes with abnormal number of chromosomes is due to non-disjunction. B) In Drosophila 'XO' males produce motile sperms. C) Sex index < 0.5 indicates intersexes in Drosophila. D) 'Y' chromosome in Drosophila lacks testis determining factor.

The blood group of the mother is B and the progeny in the family is 25 % A blood type, 25 % AB, and 50 % B blood type. What are the genotypes of the parents?

Assertion (A): The two alleles of a gene segregate from each other into the gametes; so half the gametes carry one allele of the pair and the other half carry the other allele. Reason (R): The union of one gamete from each parent to form the zygote is random.

Assertion (A): A character showing continuous variation has an unbroken range of phenotypes in a population. Reason (R): Differences are caused by allelic variation in one or many genes, while in some cases, all variation is environmental and has no genetic basis.

Homozygosity and heterozygosity of an individual can be determined by:

If a colour blind man marries a carrier woman for colour blindness, chances of their children to become colour blind is

Karyotype of Turner's syndrome is

Consider the following statements
Assertion (A): Skin colour in human beings is a polygenic trait.
Reason (R): Human skin colour is controlled by cumulative effect of genes.
The correct answer is

Choose the odd pair

Study the following and choose the correct statements:
I. Haemophilia-A and Haemophilia-B are X-linked disorders due to recessive genes
II. Sickle cell anaemia is caused by a point mutation where valine at 6th position is replaced by glutamic acid
III. Protonopia is red colour blindness
IV. Phenyl ketonuria is an allosomal metabolic genetic disorder

If a gene has four alleles, possible number of genotypes are

Consider the following statements:
Assertion (A): In human beings, Y-linked genes of non-homologous part are called holandric genes
Reason (R): Y-chromosome is present in males only

Choose the correctly matched pair