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?

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?

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?

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?