Question

In a certain species of insects, some have 13 chromosomes, and others have 14 chromosomes. The 13 and 14 chromosome-bearing organisms are ______.

Options

• males and females, respectively

• females and males, respectively

• all males

• all females

Answer 1

In certain species of insects, some have 13 chromosomes, and others have 14 chromosomes. The 13 and 14 chromosome-bearing organisms are males and females, respectively.

Explanation:

Males and females are organisms with 13 and 14 chromosomes, respectively. This is because the sex determination in this insect taxon is male heterogamety with XO type. This suggests that female eggs have an extra X chromosome in addition to autosomes. And some males have an X chromosome in their sperm, while others do not. As a result, sperm lacking an X chromosome will have one fewer chromosome than females of the same species. Males have 13 autosomes, while females have autosomes and one X chromosome.