Question

I'm making my through this test, and I came across this question:

Hemophilia is an inherited bleeding disorder where blood does not clot properly. This disorder is caused by a recessive allele on the X chromosome. A couple has just learned that their daughter has hemophilia. They already have a son who does not have the disease. What are the genotypes of the couple and the two siblings? Explain your reasoning.

Could anyone explain what it means by genotype? I know a genotype is the genetic makeup of an organism, so I don't quite understand what it's asking.

Answer 1

son not hemophiliac ... X chromosome undamaged
... inherited undamaged X from mother and Y from father

daughter hemophiliac ... both x chromosomes damaged
... inherited damaged x from mother and father

father is hemophiliac
... has damaged x chromosome
... genotype ... xY

mother is "carrier"... not hemophiliac
... has one normal X and one damaged x
... genotype ... Xx


the mother is not hemophiliac
... her phenotype is "normal"
... her genotype could be XX or Xx ... at least one undamaged X
... she carries a recessive ... because her daughter is hemophiliac
... so her genotype is Xx

because hemophilia is a sex-linked recessive
... the daughter has a damaged x from each parent

Answer 2

wow gg
thx you

Answer 3

Wow Tysm Rscott you helped me understand this whole subject

Answer 4

Dang @R_Scott your better at explaining stuff than my teachers thank you!