Question

4. Two siblings from the same parents both inherited different versions of a gene linked to heart disease. Their teacher uses a coin-flip model to show how chromosome pairs line up randomly during gamete formation. One student argues that all gametes from a parent should be identical, while another insists that random assortment explains why siblings can inherit different sets of alleles.

Which concept explains the different gene versions inherited by the siblings?

Responses

A. Fertilization, because any sperm can fuse with any egg.
A. Fertilization, because any sperm can fuse with any egg.

B. Mutations, because new alleles appear in every gamete.
B. Mutations, because new alleles appear in every gamete.

C. Mitosis, because cells divide and produce identical gametes.
C. Mitosis, because cells divide and produce identical gametes.

D. Environmental changes, because diet changes gamete formation.
D. Environmental changes, because diet changes gamete formation.

E. Independent assortment, because chromosome pairs separate into gametes randomly.

Answer 1

E. Independent assortment, because during meiosis chromosome pairs line up and segregate into gametes randomly, producing different combinations of parental alleles.

(Other choices are incorrect: fertilization can combine gametes but the coin‑flip model refers to segregation; mutations are rare and not the main cause here; mitosis doesn't make gametes; environment/diet don't create different alleles.)