View source for Y-linked

The human [[Y chromosome|Y-chromosome]] is small and contains fewer genes than the [[X_chromosome|X-chromosome]]. Therefore, there are very few Y-linked disorders. [[Retinitis pigmentosa|Retinitis pigmentosa]] is one of the Y-linked disorders. Y-linked disorders are uncommon in the human race for a number of reasons, one being that only males have a Y chromosome (females have two X chromosomes), a second reason is that the disease must be dominant; humans only have one Y chromosome - there will not be another copy of the recessive gene to make the disorder apparent in the human. There are, however, some disorders that lead to multiple Y chromosomes being present in the genotype: Y linked disoredrs will be more common in these people.