Question

The creeper gene in chickens causes short and stunted legs (creeper condition) in the heterozygous state (Cc) and lethality in the homozygous state (CC). The genotype \(c c\) produces normal chickens. What ratio is obtained when creeper chickens are Interbred? Is the \(C\) allele behaving dominantly or recessively in causing lethality?

Short answer

Also, does the C allele behave dominantly or recessively in causing lethality? Answer: When creeper chickens (Cc) are interbred, the ratio of genotypes of the offspring is 2 creeper (Cc) : 1 normal (cc). The C allele behaves dominantly in causing lethality.

Step-by-step solution

Set up the Punnett Square

A Punnett square is a grid that allows us to visualize the possible offspring genotypes resulting from a given mating event. Since both parents are heterozygous Creeper chickens (Cc), we will represent one parent's alleles on the top row of the grid and the other parent's alleles on the left column. ``` C c C [ ] [ ] c [ ] [ ] ```

Fill in the Punnett Square

Now, fill in the empty squares by combining the corresponding alleles from the parents: ``` C c C [CC] [Cc] c [Cc] [cc] ```

Determine Offspring Ratios

From the filled-in Punnett Square, we can see the following genotypes: - 1 CC (lethal) - 2 Cc (creeper) - 1 cc (normal) Remember that CC is lethal, so we will not include it in our ratio. Therefore, the ratio of genotypes obtained when creeper chickens are interbred is: 2 creeper (Cc) : 1 normal (cc)

Determine Dominant or Recessive Behavior for Lethality

Lethality occurs in the homozygous state (CC). Since the presence of two dominant C alleles leads to lethality and having only one C allele (heterozygous state) does not lead to lethality, the C allele behaves dominantly in causing lethality. In summary, the C allele is dominant in both causing creeper condition in heterozygous state and causing lethality in the homozygous state.