What is the probability of inheriting a recessive trait?

The probability of inheriting a recessive trait depends on the parents' genotypes, but it can be up to 25%.

In more detail, the inheritance of a recessive trait is determined by the combination of alleles (versions of a gene) that a person inherits from their parents. Each person has two copies of each gene, one inherited from each parent. These genes can either be dominant or recessive. Dominant genes mask the effect of recessive genes. Therefore, a recessive trait is only expressed when a person inherits two copies of the recessive gene, one from each parent.

If both parents are carriers of a recessive trait (meaning they each have one dominant and one recessive allele), there is a 25% chance that their child will inherit the recessive trait. This is because there is a 50% chance that each parent will pass on the recessive allele. The probability is calculated by multiplying these probabilities together (0.5 x 0.5 = 0.25 or 25%).

However, if only one parent is a carrier of the recessive trait, the probability that their child will inherit the trait is 0%, because the child would need to inherit the recessive allele from both parents. If both parents have two copies of the recessive allele, the probability that their child will inherit the trait is 100%, because the child will definitely inherit a recessive allele from each parent.

In summary, the probability of inheriting a recessive trait can vary from 0% to 100%, depending on the parents' genotypes. The maximum probability is 25% when both parents are carriers of the trait.