Biology Regents Practice Exam

What explains the variation in traits such as eye color and hair color among individuals?

1. Enzyme activity that varies during development.

2. The glucose units in a DNA molecule are frequently rearranged.

3. The inherited traits are determined by different gene combinations.

4. Extra genetic material is often gained during fertilization.

The correct answer is: The inherited traits are determined by different gene combinations.

The variation in traits such as eye color and hair color among individuals is primarily explained by the different combinations of genes inherited from parents. Each individual carries two alleles for each gene, one inherited from their mother and one from their father. These alleles can vary in form; for instance, a person may inherit a brown eye allele from one parent and a blue eye allele from the other. The specific combination of these genes, along with environmental factors, contributes to the wide range of phenotypic traits seen in the population. This genetic variation is crucial for promoting diversity within a species, as it increases the chances of survival under varying environmental conditions. The complex interactions of multiple genes, sometimes referred to as polygenic inheritance, also play a significant role in determining traits such as eye and hair color. Each gene can contribute to the final expression of these traits, making the outcome more intricate than if a single gene were responsible. This genetic basis accounts for the observable differences in traits among individuals.