Define autosomal dominant and recessive allele?

Autosomal Dominant and Recessive Alleles are terms used in genetics to describe how certain traits or conditions are passed down from parents to their offspring.

1. Autosomal Dominant Allele: An autosomal dominant allele is a version of a gene that can cause a particular physical trait or medical condition even if the individual only has one copy of the allele. This is because the dominant allele masks the effects of the other allele, which is known as the recessive allele. If a person has at least one dominant allele, they will exhibit the trait or condition associated with that allele. For example, if having a dominant allele causes a disease, a person only needs to inherit one dominant allele from either parent to have the disease.

2. Autosomal Recessive Allele: An autosomal recessive allele is a version of a gene that can only cause a particular physical trait or medical condition if the individual has two copies of the allele, one from each parent. This is because the effects of the recessive allele are masked by the dominant allele. If a person has only one recessive allele, they will not exhibit the trait or condition associated with that allele, but they will be a carrier and can potentially pass it on to their offspring. For example, in order for a disease that is autosomal recessive to be present, an individual must inherit two copies of the disease-causing allele, one from each parent.