Question

Which allele combination represents a male who has x-linked recessive disorder

Answer 1

The allele combination representing a male with an X-linked recessive disorder is XrY, where Xr represents the X chromosome carrying the recessive allele and Y represents the male's Y chromosome.

Step-by-step explanation:

In the context of X-linked recessive disorders, a male who expresses an X-linked recessive disorder will have one X chromosome with the mutant recessive allele and a Y chromosome without the corresponding gene (as the Y chromosome does not have most of the genes that are found on the X chromosome). Since males are hemizygous for genes on the X chromosome, having only one copy of each, the presence of a recessive allele on their X chromosome results in the expression of the disorder. For example, in the case of red-green color blindness or hemophilia, if a male inherits the recessive allele for the disorder on his X chromosome (represented as Xr), he will express the disease since there is no corresponding allele on the Y chromosome to mask it. Thus, the allele combination representing a male with an X-linked recessive disorder is XrY.

Answer 2

typically an X linked recessive disorder is denoted by a lower case superscript or first letter of the disorder.

for example, the x-linked recessive hemophilia disorder.

parents: (mother is heterozygous recessive, father doesn't have it)
Xh X + XY

offspring
Xh Y (X-linked rec disorder male)
X Y (normal male)
Xh X (hetero, rec, female)
X X (homo, normal, female)