Lauren’s father and her three brothers are all colorblind and have Duchenne Musc

ID: 258681 • Letter: L

Question

Lauren’s father and her three brothers are all colorblind and have Duchenne Muscular dystrophy. Lauren has neither condition. The gene associated with colorblindness (OPN1LW) and the gene associated with Duchenne Muscular dystrophy (DMD) are located 27cM apart. Both the OPN1LW and DMD are found on the X-chromosome.

A. Lauren and her husband are about to have a baby boy. If her husband has normal vision and has normal muscle function, what is the probability that their sonis colorblind but does not have Duchenne Muscular dystrophy?

b. What is the chance that their son is not colorblind and does not have Duchenne Muscular dystrophy?

c. What is the probability of having a daughterthat is colorblind but does not have Duchenne Muscular dystrophy?

Explanation / Answer

Answer:

Based on the information the Lauren is carrier for both the disesases.

Colorblind allele = c ; Normal color vision=C

Muscular dystrophy = d; norml muscle = D

XCD Xcd (Lauren) x (Husband) XCD Y

Distance between genes = Recombination frequency

27 cM = 27 % recombinant progeny

XCD (50%)

Y (50%)

XCD (36.5%)

XCD XCD (36.5% * 50% = 18.25%) Normal

XCDY (36.5% * 50% = 18.25%) normal

XCd (13.5%)

XCD XCd (13.5% * 50% = 6.75%) normal

XCd Y (13.5% * 50% = 6.75%) muscular distrophy

XcD (13.5%)

XCD XcD (13.5% * 50% = 6.75%) normal

XcD Y (13.5% * 50% = 6.75%) colorblind

Xcd (36.5%)

XCD Xcd (36.5% * 50% = 18.25%) normal

Xcd Y (36.5% * 50% = 18.25%) colorblind and musclular distrophy

a). The probability that their sonis colorblind but does not have Duchenne Muscular dystrophy = 6.75%

b).Tthe chance that their son is not colorblind and does not have Duchenne Muscular dystrophy= 18.25%

c). The probability of having a daughter that is colorblind but does not have Duchenne Muscular dystrophy = 0%

All daughters are normal for both the diseases.