Sex Chromosomes and Genetic Mechanisms

This set of flashcards covers key concepts related to sex chromosomes, genetic mechanisms, meiosis, and associated human conditions.

What is the primary function of the SRY gene on the Y chromosome?

The SRY gene is the primary determinant of maleness and activates testes development.

What is Meiosis I characterized as?

Meiosis I is a reductional division that reduces the chromosome number by half.

What occurs during Interkinesis?

Interkinesis is the growth phase between Meiosis I and Meiosis II, similar to interphase but without DNA synthesis.

How does Meiosis II differ from Meiosis I?

Meiosis II is an equational division where sister chromatids separate and the number of chromosomes remains the same.

What is the result of independent assortment during meiosis?

Independent assortment creates different combinations of alleles.

How many genes are approximately found on the X chromosome compared to the Y chromosome?

The X chromosome contains approximately 850 genes, while the Y chromosome contains about 50 genes.

What characterizes a heterogametic sex?

Heterogametic sex has two different sex chromosomes and can produce two different types of gametes.

Give an example of a sex-linked disease in humans.

Red-green colorblindness is an example of an X-linked recessive trait.

What mechanism do mammals use for dosage compensation?

In mammals, one X chromosome in females is randomly inactivated, forming a Barr body.

What conditions are associated with Turner Syndrome?

Individuals with Turner Syndrome have a single X chromosome and display short stature, developmental disorders, and infertility.

What defines Klinefelter Syndrome?

Klinefelter Syndrome is characterized by at least one extra X chromosome (47, XXY) leading to underdeveloped testes and infertility.

What is a criss-cross inheritance pattern?

Criss-cross inheritance occurs when males inherit traits from their mothers and daughters inherit traits from their fathers, commonly seen in X-linked traits.

Describe the difference between sex-limited and sex-influenced traits.

Sex-limited traits are expressed in only one sex, while sex-influenced traits are present in both sexes but more pronounced in one.