How does probability help explain the results of a genetic cross? - Answers

Genetics often involves dominant and recessive alleles. For instance, blue eyes are recessive and brown eyes are dominant.1 Each parent contributes one allele. If you get two blues, then your eyes are blue. If you get one or two browns, then you eyes are brown. That means that, given a random contribution from your parents, you have a 25% probability of blue eyes. It also means that, even though you have brown eyes, you could be carrying the blue allele, and two parents with brown eyes could have a blue eyed child. ------------------------------------------------------------------ 1Its more complicated than that, since eye color is actually polygenic, involving more than one allele. This example was simplified to answer the question.