Principles of Inheritance and Variation · Biology · IAT (IISER)
MCQ (Single Correct Answer)
1
The following pedigree diagram shows the inheritance of a rare genetic disorder (filled shapes depict affected individuals).
Which of the following is the most likely pattern of inheritance of the disorder?

IAT (IISER) 2024
2
In an island with 10,000 individuals, four have sickle cell anemia, a recessive autosomal disease. Assuming that the locus is in Hardy-Weinberg equilibrium, how many individuals in that island are expected to be heterozygous for the disease allele?
IAT (IISER) 2023
3
The following pedigree chart shows the inheritance of a genetic disorder. I-2 and III-2 are the only affected individuals.
Which one of the following is the correct pattern of inheritance of the disorder, and the genotype of the II- 3 individual?

IAT (IISER) 2023
4
In a given species of flowering plant, the colour of the seeds is exclusively determined by the colour of its seed coat. Seed coat colour in this species is governed by a nuclear gene with two alleles. The WHITE ( $W$ ) allele is dominant over brown ( $w$ ) allele. If a plant with brown seeds $(w w)$ is crossed as a female with pollen from a white seed $(W W)$ plant, what will be the seed colour and the genotype of the embryo in the resultant seeds obtained from this cross?
IAT (IISER) 2022
5
A single point mutation in gene ' $X$ ' results in breathing difficulty, hypertension as well as partial sterility. Which among the following best explains the observed phenotypes?
IAT (IISER) 2022
6
In a cross between individuals of the genotypes PpQQRrSS and ppqqRrSS, what will be the expected number of progenies with the genotype ppQQRrSS in a population of 400 individuals, assuming independent assortment?
IAT (IISER) 2022
7
Nine percent of a population cannot taste a certain food item because of a recessive allele of the gene IAT. Assuming the population is in Hardy-Weinberg equilibrium, what will be the frequency of dominant and recessive alleles, respectively?
IAT (IISER) 2022
8
A hypothetical plant species shows two flower colour phenotypes- red and white. Red is dominant over white. In a population, this flower colour locus was found to be in HardyWeinberg equilibrium. If 490 out of a total population size of 1000 plants were found to be white-flowered, how many of the red-flowered plants will be heterozygous?
IAT (IISER) 2020