Scurs are small horn-like growths in cattle that exhibit sex-influenced inheritance.The allele that determines scurs (Sc)is dominant in males and recessive in females.From a mating between a heterozygous male with scurs and a heterozygous female without scurs,what proportion of male offspring will lack scurs (be hornless)?
A) 0%
B) 25%
C) 50%
D) 75%
E) 100%

Question

Quizplus · Accepted Answer

The Punnett square for the given cross is:

S   s
S  SS  Ss
s  sS  ss

From this, we can see that half of the male offspring will inherit the dominant allele for scurs (Ss) and have scurs, while the other half will inherit the recessive allele for hornlessness (ss) and lack scurs. Therefore, the proportion of male offspring that will lack scurs is 1/2 or 25%.

Scurs Are Small Horn-Like Growths in Cattle That Exhibit Sex-Influenced