Question

genes a and b are both on chromosome 1. which of the following accurately depicts the content of a zygote formed when an ab gamete is fertilized by an ab gamete?
d
a
b
c
both c and d

Explanation:

Step1: Understand zygote formation

A zygote is formed by the fusion of two gametes. One gamete is \(Ab\) and the other is \(aB\).

Step2: Analyze chromosome content in zygote

When \(Ab\) (with one chromosome having \(A\) and \(b\)) fuses with \(aB\) (with one chromosome having \(a\) and \(B\)), the zygote will have two chromosomes. One chromosome will have \(A\) and \(b\) (from \(Ab\) gamete) and the other will have \(a\) and \(B\) (from \(aB\) gamete).

Step3: Check each option

• Option a: Has two separate sets of chromosomes but not in the correct combined form as per gamete fusion.
• Option b: Has a single chromosome - incorrect as zygote has two (from two gametes).
• Option c: Has two chromosomes, one with \(A,a\) and \(b,B\) (representing the two gametes \(Ab\) and \(aB\) fusing).
• Option d: Shows two separate non - homologous - like structures, but in reality, in a zygote (diploid for these chromosomes), we have two homologous - like chromosomes (one from each parent gamete). But in terms of gene content (as genes \(A\) and \(B\) are on chromosome 1, we assume proper pairing representation in c.

Answer:

C