Answer:
Long tail (Ll) = 1/2 or 50%
Short tail (ll) = 1/2 or 50%
Explanation:
This question involves a single gene coding for tail length in grackle birds. The allele for long tails (L) were dominant to short tails (l) in these birds. This means that a bird that is heterozygous (Ll) for the gene will be phenotypically long tailed.
According to the question, a female short-tailed grackle (ll) mates with a male long-tailed grackle that had one parent with a long tail and one parent with a short tail. This male grackle will have a genotype: Ll because of his parental genotype. Hence, crossing ll × Ll, the following gametes will be produced by each parent:
Ll (male) = L and l
ll (female) = l and l
Using these gametes in a punnet square (see attached image), the following proportion of offsprings will be produced:
Ll, Ll, ll and ll
2 Ll out of 4 are long-tailed i.e 1/2 or 50% probability
2 ll out of 4 are short-tailed i.e 1/2 or 50% probability
