Read More on This Topic. Info Print Cite. If the Sox9 gene does not turn on in an embryo with XY sex chromosomes, the gonads develop into ovaries, and the individual becomes a female anatomically. Sex linked is a trait in which a gene is located on a sex chromosome.
The traits governed by these genes thus show sex-linked inheritance. Subsequently, genes on that chromosome not coding for gender are usually expressed in the male phenotype even if they are recessive since there are no corresponding genes on the Y chromosome in most cases.
Queen Victoria with her husband and nine children in By comparison to the X chromosome, the much smaller Y chromosome has only about 26 genes and gene families. At meiosis the X and Y chromosomes first pair then disjoin and pass to different cells.
In humans, the term generally refers to traits that are influenced by genes on the X chromosome. In humans, for example, the Xor female-determining, chromosome carries many genes, whereas the Yor male-determining, chromosome is deficient in genes.
This indicates that Y chromosomes have been evolving at a much faster rate than the X and all other chromosomes. At meiosis the X and Y chromosomes first pair then disjoin and pass to different cells. Because the Y chromosome only experiences recombination with the X chromosome at the ends as a result of crossing-overthe Y chromosome essentially is reproduced via cloning from one generation to the next.
Return to Menu. A man a Y carrier has no opposite-acting genes on the Y chromosome that could influence or suppress the action of the genes on the X chromosome. If the Sox9 gene becomes active in an embryo with two X chromosomes, it causes male gonads to form instead of ovaries, and the individual develops into an anatomical male.
Be on the lookout for your Britannica newsletter to get trusted stories delivered right to your inbox. In a sex-linked disease, it is usually males who are affected because they have a single copy of X chromosome that carries the mutation.