A long-haired cat (recessive trait s) is crossed with a heterocygous short-haired cat (dominant trait S). What percentage of their offspring will have long hair?
A. 100 percent
B. 50 percent
C. 25 percent
D. 0 percent
Is the answer C?
Yes, the answer is C. 25 percent.
To understand how we arrive at this answer, let's break down the problem and the concepts involved.
In this scenario, the long hair trait (recessive s) is crossed with the short hair trait (dominant S), following Mendelian inheritance patterns.
The genotype of the long-haired cat is ss, meaning it has two copies of the recessive trait.
The genotype of the heterozygous short-haired cat is Ss, meaning it has one copy of the dominant trait and one copy of the recessive trait.
To determine the percentage of offspring with long hair, we need to analyze the possible outcomes of their offspring's genotypes.
When the long-haired cat (ss) is crossed with the heterozygous short-haired cat (Ss), their possible offspring genotypes are as follows:
- 50 percent will inherit one copy of the recessive trait (s) and one copy of the dominant trait (S), resulting in the genotype Ss. These cats will have short hair.
- 50 percent will inherit two copies of the recessive trait (s), resulting in the genotype ss. These cats will have long hair.
Therefore, only 25 percent of the offspring (50 percent of the 50 percent) will have long hair (genotype ss).
Thus, the correct answer is C. 25 percent.