4 Regarding sex chromosomes a How many copies of each gene i

4. Regarding sex chromosomes:

a.) How many copies of each gene in the pseudautosomal region do human males have?

b.) How does the inheritance of genes in this region differ from the inheritance of other Y-linked characteristics?

Solution

a)2 copies of genes are present in the pseudautosomal regions which males have. This includes one in the pseudoautosomal region of their Y chromosome.On the other hand,another one is present in the corresponding portion of their X chromosome.As a result we have 2 copies of gene.

b)As explained earlier ,males have 2 copies of genes in this region.One of them is present in the pseudoautosomal region of their Y chromosome whereas the other one is present in the corresponding portion of their X chromosome. Lets talk about the females now,The females also possess two copies of pseudoautosomal genes,Moreover, each of their two X chromosomes, they contain a pseudoautosomal region. The process of crossing over between the X and Y chromosomes is usually restricted to the pseudoautosomal regions; .This means that in terms of inheritance, the pseudoautosomal genes exhibit an autosomal instead of a sex-linked, pattern of inheritance.Furthermore the , females are able to inherit an allele which is originally present on the Y chromosome of their father unlike the normal -linked characteristic in which it is inherited from Y chromosome.