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  • a. In humans, males are heterogametic, and females are homogametic. Explain. Are there any examples where males are homogametic and females heterogametic? b. Also describe as to, who determines the sex of an unborn child?

a. In humans, males are heterogametic, and females are homogametic. Explain. Are there any examples where males are homogametic and females heterogametic?

b. Also describe as to, who determines the sex of an unborn child? Mention whether the temperature has a role in sex determination.

Answers (1)

1. In humans, males are called heterogametic because they have X and Y chromosomes in their 23rd pair of the chromosome. On the other hand, females are called homogametic as they have two same chromosomes, i.e. XX chromosomes in their 23rd pair of the chromosome. However, in birds, the scenario is quite the opposite. Male birds have ZZ chromosomes, and female birds have ZW chromosomes. Hence, in cases like these, males are homogametic, and females are heterogametic.

2. The sex of an unborn child is determined by the 23rd pair of chromosome in humans. The males have X and Y chromosomes and females have X and X chromosomes in that pair. So, when the ovum is fertilized with the sperm containing X chromosome, the result is a female child, and when it is fertilized with the Y chromosome, the result is a male child. In some animals like crocodiles, the sex is determined by temperature. Male crocodiles are born if eggs are brooded at high temperatures.

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