Hemophilia is a genetic disorder that inherited by X-linked recessive pattern. A daughter needs 2 genes to have the disease(or 1 gene to become carrier) but a son only needs to get 1 defect genes from his mother(X gene in male must come from mother). If Xh defected gene and X normal genes, the <span>punnett square </span>would be:
Father(XY)
X Y
Mother Xh XhX XhY ------>XhX= carrier , XhY= sick
(Xh X) X XX XY ------>healthy
Answer:
Considering the <u>whole progeny</u> (100%), there will be
- 25% Black male kittens, XBY
- 0% Calico Male kittens
- 25% Calico female kittens, XBXR
Explanation:
<u>Available data:</u>
- The gene for Calico (multicolored) cats is an x-linked trait and codominant
- Calico Females receive a "B" and an "R" gene, and have black and orange splotches on white coats. Their genotype is XBXR.
- Males can only be black or orange, but never calico. Their genotype is XBY and XRY
Cross: a female calico cat with a black male
Parentals) XBXR x XBY
Gametes) XB XR XB Y
Punnett square) XB XR
XB XBXB XBXR
Y XBY XRY
F1) Among the whole progeny:
- 2/4 = 50% will be black (female XBXB and male XBY)
- 1/4 = 25% will be Calico (female XBXR)
- 1/4 = 25% will be Orange (male XRY)
Among females:
- 1/2 = 50% of females will be black, XBXB
- 1/2 = 50% of females will be Calico, XBXR
Among males:
- 1/2 = 50% of males will be black, XBY
- 1/2 = 50% of males will be orange, XRY
