In chickens, the allele for a pea comb (A) is dominant to the allele for a single comb (a).
A mother with the genotype Aa and a father with the genotype Aa produce an offspring.
What is the percent chance that the offspring will have a single comb?

In chickens, the allele for a pea comb (A) is dominant to the allele for a single comb (a).  A mother with the genotype Aa and a father with the genotype Aa produce an offspring.  What is the percent chance that the offspring will have a single comb?

A= Pea comb

a= single comb

Aa x Aa= AA, Aa, Aa and aa

The percentage of having offspring with single comb is 25% as others with pea comb makes 75% with two homozygous (Aa dominant pea comb and aa  recessive single comb) and two heterozygous (Aa and Aa)

Explanation:

The percentage chance that the offspring will have a single comb is 25%

Explanation: A cross between a mother with genotype Aa and a father with genotype Aa will produce four offsprings: 1AA, 2Aa and 1aa, i.e., Aa x Aa = AA, Aa, Aa and aa.

Genotypes AS and Aa will manifest as pea comb while genotype aa will manifest as single comb. This means that one offspring out of the four has a single comb.

Therefore, the percentage chance of having an offspring with a single comb is 1/4 x 100 = 25%

Punnet square

- A a

A AA AA

a Aa aa

answer: land bridge theory. land bridge theory held that shifting portions of dry land explained the finding of identical species on different continents. plate tectonic theory eventually eliminated the land bridge theory.

in 1859, charles darwin set out his theory of evolution by natural selection as an explanation for adaptation and speciation. he defined natural selection as the "principle by which each slight variation [of a trait], if useful, is preserved".