What Determines Baby's Sex?
The SRY gene on the Y chromosome triggers male development.
In its absence, the default pathway leads to female development.
The SRY Gene and Its Role
All eggs contain one X chromosome; sperm carry either an X or Y chromosome.
An XY combination (with SRY) develops into a male, while XX develops into a female.
SRY Gene in Females
Rare cases have seen women with an SRY gene on the X chromosome (translocation).
These women typically develop as biological males with testes, but they remain infertile due to missing Y chromosome genes.
Exceptions in SRY-Positive Females
Some SRY-translocation females develop normally as females.
In these cases, a portion of the X chromosome is deleted, allowing for the normal expression of the SRY gene.
Role of X Chromosome Inactivation
In females, one of the X chromosomes is inactivated to ensure equal gene expression.
In exceptional cases, biased X inactivation silences the SRY gene, allowing for female development.
Potential Health Concerns
There’s concern that low-level expression of the SRY gene later in life could cause sex development disorders.
Long-term studies are necessary for monitoring these rare cases.
Future Implications
Understanding these SRY translocations can help genetic counseling and medical decision-making.
Ongoing research is essential to uncover the impact of these rare genetic occurrences.
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