Question

In mice, black coat colour (allele $B$) is dominant to brown coat colour (allele b). The offspring of a cross between a black mouse $(BB)$ and a brown mouse $(bb)$ were allowed to interbreed. What percentage of the progeny would have black coats ?

• A. $25\%$
• B. $50\%$
• C. $75\%$
• D. $100\%$

Answer 1

Answer: (C)

$75\%$

Answer 2

The cross between black mouse $(BB)$ and a brown mouse $(bb)$ and the inbreeding of their hybrid progeny is shown below. Hence, phenotypic ratio is $3$ black : $1$ brown i.e. $75\%$ of the progeny would have black coat.