How do sex-linked genes function in inheritance patterns?

Sex-linked genes are located on the sex chromosomes, X and Y, and exhibit unique inheritance patterns.

Sex-linked genes are inherited differently than autosomal genes because males only have one X chromosome, while females have two. This means that if a male inherits a recessive allele on his X chromosome, he will express the trait because he has no second X chromosome to mask it. In contrast, females need to inherit two copies of the recessive allele to express the trait.

The most well-known example of a sex-linked gene is the gene for hemophilia, a blood clotting disorder. Hemophilia is caused by a recessive allele on the X chromosome, so males are more likely to inherit the disorder than females. Females can only inherit hemophilia if both of their X chromosomes carry the recessive allele, which is much less common than in males.

Another example of a sex-linked gene is the gene for red-green color blindness. This condition is also caused by a recessive allele on the X chromosome, so males are more likely to be color blind than females. Females can only be color blind if both of their X chromosomes carry the recessive allele, but they can still be carriers of the trait and pass it on to their offspring.

Overall, sex-linked genes play an important role in inheritance patterns and can lead to unique phenotypic outcomes. Understanding these patterns is crucial for predicting the likelihood of certain traits and disorders in offspring.