Question

Hemophilia is sex-linked recessive, and this gene is located on the X-chromosome. If the letter “h” is used, how would you write the genotype for a male that has this disorder?
A.
X^H Y
B.
X^h Y
C.
x^h Y
D.
X^h y

Answer 1

B. X^h Y

Males are XY, so a single recessive allele on their X chromosome (X^h) causes the X-linked recessive disorder.