Question

If the cell of an organism heterozygous for two pairs of genes represented by Xx, Zz undergoes meiosis, then the possible genotypic combination of gametes will be
A. XZ; xz; Xz; xZ
B. XZ; xz; Xz
C. Xx; Zz, Xz
D. Data incomplete

Answer 1

Hint: For any given organism the combination obtained from genes can be expressed as $$2^n$$, where n denotes the number of gene pairs. In the formation of gamete, the alleles are independently segregated from each other.

Complete answer:
When considering recombination which occurs during meiosis, the number of combinations that can be obtained is denoted by the formula $$2^n$$ where n denotes the number of gene pairs. If there is one gene there would be two combinations, 2 genes 4 combinations, 3 genes 8 combinations, etc.
The question denotes two pairs of genes that are heterozygous and are undergoing meiosis. The first pair is denoted by Xx where one is a dominant gene and the other is a recessive gene, and similar for Zz.
During recombination, we know that the alleles of each gene will separate independently and recombine with each other. Therefore, we have X, x, Z, and z and the resultant genotype of the gametes will have either XZ, xz, Xz, xZ.
Therefore, the correct answer is A.

Note: The entire question depends upon the understanding of the idea of recombination. Here a cell of two pairs of genes undergoes meiosis to produce haploid gametes. A haploid gamete will only contain one allele from each pair of genes. Thus only one allele from the Xx gene and one allele from the Zz gene will be present in each gamete. It is important to understand that this is cell division in meiosis where a diploid divides into a haploid cell.