SAT Subject Biology Practice Question 288: Answer and Explanation
18. In chickens, the allele for long tail feathers (T) is dominant over the allele for short tail feathers (t). If a pure-breeding long-tailed chicken (TT) mates with a pure-breeding short-tailed chicken (tt), what percentage of their offspring (if mated with the correct genotype) could give rise to chickens with long tails?
E. unable to determine from the information given
Correct Answer: D
D If a pure-breeding long-tailed chicken (TT) mates with a pure-breeding short-tailed chicken (tt), all of their offspring (the F1 generation) will have the genotype Tt (and have long tails). Thus all of them could produce offspring with long tails.