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💀anatomy and physiology i review

SRY Gene

Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025

Definition

The SRY (sex-determining region Y) gene is a critical genetic factor that plays a pivotal role in male sexual development and the determination of biological sex. This gene is located on the Y chromosome and is responsible for triggering the cascade of events that lead to the formation of male reproductive organs and characteristics during embryonic development.

5 Must Know Facts For Your Next Test

  1. The SRY gene is the master regulator of male sexual development, initiating the cascade of events that lead to the formation of testes and other male reproductive organs.
  2. The presence of the SRY gene on the Y chromosome is the primary determinant of biological sex, as it triggers the development of testes rather than ovaries.
  3. The SRY gene acts by upregulating the expression of other genes involved in male sexual differentiation, such as SOX9, which is crucial for testis formation.
  4. Mutations or deletions in the SRY gene can lead to disorders of sexual development, such as Swyer syndrome, where individuals with XY chromosomes develop female external genitalia and secondary sexual characteristics.
  5. The SRY gene is also involved in the regulation of brain development and the expression of male-specific behaviors, contributing to the overall sexual dimorphism observed in humans.

Review Questions

  • Explain the role of the SRY gene in the development of the male reproductive system.
    • The SRY gene, located on the Y chromosome, is the primary genetic factor responsible for initiating male sexual development. It triggers a cascade of events that lead to the formation of testes and other male reproductive organs. The presence of the SRY gene causes the undifferentiated gonad to develop into testes, which then produce testosterone, the key male sex hormone. This hormone drives the development of male secondary sexual characteristics and the maturation of the male reproductive system.
  • Describe how the SRY gene influences fetal development and the determination of biological sex.
    • The SRY gene is the crucial genetic switch that determines biological sex during fetal development. If the SRY gene is present, it triggers the development of testes and the male reproductive system. In the absence of the SRY gene, the undifferentiated gonad will develop into ovaries, and the fetus will follow the female developmental pathway. The presence or absence of the SRY gene is the primary determinant of whether an individual will develop as male or female, making it a central player in the process of sexual differentiation during fetal development.
  • Analyze the potential consequences of genetic abnormalities or mutations in the SRY gene and their impact on sexual development and disorders of sexual development.
    • Genetic abnormalities or mutations in the SRY gene can have significant consequences for sexual development and lead to disorders of sexual development (DSDs). For example, a deletion or inactivation of the SRY gene can result in Swyer syndrome, where individuals with XY chromosomes develop female external genitalia and secondary sexual characteristics, despite the presence of the Y chromosome. Conversely, duplications or mutations that cause overexpression of the SRY gene can lead to the development of male characteristics in individuals with XX chromosomes. These genetic variations underscore the critical role of the SRY gene in the determination of biological sex and the importance of its proper regulation during fetal development.