Question

In humans, "unattached" earlobes are dominant over "attached" earlobes. "Widows peak" hairline is dominant over "non-widows peak" hairline. Use E and e for the earlobe phenotype alleles, and W and w for the hairline phenotype alleles. A female and a male, both with genotype EeWw have a child. What is the probability it will be a boy, and have attached earlobes and a widows peak hairline?

Answer 1

3/32

Step-by-step explanation:

The probability would be 3/32

From the illustration:

• Unattached earlobe E is dominant over attached earlobe e.
• Widows peak hairline is dominant over non-widows peak hairline.

EeWw and EeWw were crossed (Assuming both traits are autosomal)

EeWw x EeWw

Progeny :

1 EEWW - unattached earlobe with widows peak

2 EEWw - unattached earlobe with widows peak

2 EeWW - unattached earlobe with widows peak

4 EeWw - unattached earlobe with widows peak

1 EEww - unattached earlobe with non-widows peak

2 Eeww - unattached earlobe with no-widows peak

1 eeWW - attached earlobe with widows peak

2 eeWw - attached earlobe with widows peak

1 eeww - attached earlobe with no-widows peak

Generally, the probability of obtaining a male or a female in a cross is 50/50 or 1/2.

From the crossing result, the probability of having attached earlobe and widows peak hairline is 3/16.

Hence, the probability of obtaining a boy with attached earlobes and widows peak airline:

1/2 x 3/16 = 3/32.