Question

XX - XO sex chromosome complement occurs in:
A. Cockroach
B. Honeybee
C. Human beings
D. Chimpanzee

Answer 1

Hint: XX - XO sex determination system is exhibited by common insects which may be one of the simplest living Neopteran insects with few unique adaptations. The head and large flattened body are relatively small, and most of its species are reddish-brown to dark brown.

Complete answer:
In organisms such as cockroach, the female is XX and the sex is homogametic. The male is a heterogametic sex, but he has only one sex chromosome. The male in XX-XO systems produces gametes with (X) or without (O) sex chromosomes.

The XY sex-determination system is a sex-determination system used to identify many species, including humans, some insects (Drosophila), etc. The sex of a person in this system is determined by a pair of sex chromosomes. Females usually have two of the same sex chromosome (XX) and are referred to as homogametic sex. Males usually have two distinct forms of sex chromosomes (XY) and are considered heterogametic sex.

In the case of honeybees (or honeybees), sex is typically determined by fertilization or non-fertilization of eggs, rather than by the presence or absence of sex chromosomes. In haplodiploid systems, male offspring typically develop from unfertilized eggs, which are haploid and have only one set of chromosomes.

There are 23 chromosome pairs in humans, and 24 chromosomes in the other great apes such as chimpanzees.

Hence, The correct answer is option (A).

Note: In insects such as cockroach, male is the heterogametic sex (XO) and female is the homogametic sex (XX), hence, these organisms possess XX - XO sex determination system. Person with an XO chromosome suffers from Turner's Syndrome. Such females are called sterile females because they have an absence of secondary sexual character.