Question

Hemophilia is a gender-linked blood disorder in humans. The gene responsible for it is gene-linked recessive, meaning it is present on the X chromosome. When the gene is present in males (Xh), it always expresses itself, meaning that the male's blood won't clot properly. When present in females in a heterozygous condition (XhXH), the gene doesn’t express itself; but the female becomes a carrier, meaning that her offspring could have hemophilia.. When present in a homozygous recessive condition in females (XhXh), it expresses itself. One of every 10,000 persons is affected by this disease. What could be the allele frequency for this disease in the entire population?

Answer 1

The frequency will be one in a ten thousand, in a real life situation. The X-linked recessive disorder has the same frequency as that of its frequency in the men. The frequency in women is close to zero, and in 5000 men, it will be one, so in total, the allele frequency will be 1/10000.
When we use a Punnett sqare, it comes out that 0% of the females will have he disease. But, as 50% of the eggs of the mother will  carry a recessive allele, 50% of the male offprings bear the cahnces of being affected, i.e., 25% of the total offsprings, which mean 2500 male children bear the chance of having Hemophilia.