In rabbits, the gene for grey fur (G) is dominant over that for black fur (g). In a litter, if 50\% rabbits are grey, then the possible parental cross combination is

• A

  $\mathrm{GG} \times \mathrm{Gg}$
• B

  $G G \times G G$
• C

  $g g \times g g$
• Correct answer
  D

  $\mathrm{Gg} \times \mathrm{gg}$.

Solution

When heterozygous grey individuals $(\mathrm{Gg})$ are crossed with homozygous black individuals (gg), then grey and black individuals will be obtained in equal ratio. It is a type of test cross and can be illustrated as:

Hence, the correct answer is option: 'D'.