Sry gene

Definition

The sry gene, or sex-determining region Y gene, is a critical gene located on the Y chromosome that is responsible for the initiation of male sex determination in mammals. This gene produces a protein known as the SRY protein, which triggers the development of male reproductive structures by promoting the formation of testes and inhibiting female pathway development. Its function is essential for the proper formation of the male urogenital system.

5 Must Know Facts For Your Next Test

1. The sry gene was discovered in the 1990s as a key determinant for male sex development in mammals.
2. Activation of the sry gene occurs early in embryonic development, around week 6 in humans, leading to the formation of testes.
3. Without a functional sry gene, an individual with XY chromosomes may develop female characteristics due to the lack of testis formation.
4. The SRY protein functions as a transcription factor that activates other genes necessary for testicular development and suppression of ovarian pathways.
5. Mutations in the sry gene can lead to disorders of sexual development, such as Swyer syndrome, where individuals have XY chromosomes but develop as females.

Review Questions

• How does the activation of the sry gene influence gonadal development?
  • The activation of the sry gene is crucial for gonadal development because it leads to the production of the SRY protein, which functions as a transcription factor. This protein activates downstream genes that promote testis formation while simultaneously inhibiting the pathways that would lead to ovarian development. The presence of functional testes ultimately drives the development of male secondary sexual characteristics.
• Discuss the consequences of a non-functional sry gene on sexual differentiation in XY individuals.
  • A non-functional sry gene in XY individuals can result in complete or partial androgen insensitivity syndrome. These individuals may develop external female genitalia and secondary sexual characteristics despite having XY chromosomes. The lack of SRY protein prevents testicular formation, leading to an absence of male hormones that are critical for developing male reproductive anatomy. Therefore, they present phenotypically as females while having a male genetic constitution.
• Evaluate how mutations in the sry gene can affect reproductive health and development in humans.
  • Mutations in the sry gene can lead to various disorders related to sexual development, significantly impacting reproductive health. For instance, individuals with Swyer syndrome possess an XY chromosome pattern but develop as females due to mutations that render the sry gene non-functional. This results in undeveloped gonads and infertility. Such cases illustrate the importance of the sry gene not just in determining male sex but also in maintaining overall reproductive health and functioning.

Related terms

Testis Determining Factor (TDF): A protein encoded by the sry gene that initiates male sex differentiation by inducing testicular development.

Gonadal Development: The process by which undifferentiated gonads develop into either ovaries or testes, influenced by genetic factors like the sry gene.

Sexual Differentiation: The biological process by which individuals develop male or female anatomical and physiological characteristics, guided by genes like the sry.