Summary
The SRY gene on the Y chromosome triggers male development in mammals.
In depth
SRY triggers Sertoli cells, testis development and anti-Müllerian hormone; testosterone leads to male internal and external genitalia. Without SRY, ovaries form. Chromosomal sex and phenotype may differ in conditions like androgen insensitivity.
Gonads are initially bipotential. SRY activates SOX9; without SRY, WNT4 and FOXL2 favour ovaries. Hormones then shape duct systems and external genitalia.
Example: androgen insensitivity syndrome gives XY individuals with female external features.
Frequently asked questions
What is Sex Determination?
The SRY gene on the Y chromosome triggers male development in mammals.
Which area of biology covers Sex Determination, and how advanced is it?
Sex Determination is one of the 54 topics in Developmental Biology. It is rated Intermediate, so it suits learners who already know the core vocabulary. Related topics in this area include Metamorphosis in Amphibians, Apoptosis in Development, Maternal Effect Genes.
Can you give an example of Sex Determination?
Some reptiles determine sex by egg temperature.
What should I learn before Sex Determination?
Work through the Beginner topics in Developmental Biology first, such as Fertilisation, Zygote, Embryo, then return to Sex Determination. Intermediate topics assume the Beginner vocabulary.
What topics are related to Sex Determination?
The closest topics to Sex Determination are Metamorphosis in Amphibians, Apoptosis in Development, Maternal Effect Genes, Left-Right Asymmetry. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Sex Determination?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Sex Determination. To practise the whole of Developmental Biology, use the Developmental Biology quiz.
How is Sex Determination different from Metamorphosis in Amphibians?
Sex Determination: The SRY gene on the Y chromosome triggers male development in mammals. Metamorphosis in Amphibians: Thyroid hormones trigger the tadpole to frog change, including tail loss and limb growth. Read both side by side and note what each one explains.
How should I study Sex Determination step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Metamorphosis in Amphibians and explain the difference aloud. Finally, take the Developmental Biology quiz and come back to this page for any question you miss.