Optimistic Outlook: Exploring Cow Color Genetics
What alleles will the offspring have if a red cow (homozygous dominant) is crossed with a white cow (homozygous dominant)?
a) All red cows (homozygous dominant).
b) All white cows (homozygous dominant).
c) Red and white cows (heterozygous dominant).
d) Black and white cows (heterozygous recessive).
Answer:
Both combinations result in heterozygous dominant offspring, meaning the offspring will have a combination of red and white color. Therefore, the correct answer is c) Red and white cows (heterozygous dominant).
When a red cow (homozygous dominant) is crossed with a white cow (homozygous dominant), the offspring will inherit one allele from each parent. In this case, the red cow has two copies of the dominant allele for red color (RR), and the white cow also has two copies of the dominant allele for white color (WW).
The dominant allele for red color (R) is represented by a capital letter, and the dominant allele for white color (W) is also represented by a capital letter. Since both parents are homozygous dominant, their alleles do not carry the recessive allele for black color (r). The recessive allele for black color is represented by a lowercase letter.
When the red cow (RR) is crossed with the white cow (WW), the offspring will inherit one allele from each parent. Therefore, the possible combinations of alleles in the offspring are:
- Red cow (R) from the red parent and white cow (W) from the white parent: RW
- White cow (W) from the red parent and red cow (R) from the white parent: WR
It's important to note that this explanation assumes a simple Mendelian inheritance pattern and does not take into account other factors that could influence color inheritance in cows.