Question

Two alleles of gene C control hair color in horses: C1 and C2. Horses

homozygous for allele C1 are red, heterozygotes are yellow, and C2 homozygotes are cream. In the offspring of matings between heterozygotes, what phenotypic ratio is expected?
- 1 red: 2 yellow: 1 cream
- 3 red: 1 cream
- 2 yellow: 1 red
- 9 red: 3 yellow: 4 cream
- all red

Answer 1

The expected phenotypic ratio for offspring of two heterozygous horses is 1 red: 2 yellow: 1 cream, following a simple Medelian inheritance pattern.

Step-by-step explanation:

The inheritance pattern described for horses follows a simple Mendelian inheritance with two alleles controlling the trait, where C1 is dominant for red color, and C2 is recessive leading to cream color when in a homozygous state. In heterozygotes, the phenotype is yellow. When two heterozygotes (C1C2) are crossed, the expected phenotypic ratio is 1 red: 2 yellow: 1 cream, resulting from the following genotypic combinations: C1C1 (red), C1C2 (yellow), C2C1 (also yellow), and C2C2 (cream).

Using a Punnett square, we can visualize the offspring distribution:

• C1C1 (Red)
• C1C2 and C2C1 (Yellow)
• C2C2 (Cream)

As such, we can derive the final phenotypic ratio easily, showing the colors and their amount in a single generation from two heterozygous parents.