Recessive Alleles: Explaining Inheritance Patterns and Genetic Conditions

recessive allele

the weaker allele. This trait will only show up in the offspring if the dominant allele is not present, and two recessive alleles are present. Represented by a lower case letter

In genetics, an allele is a variant of a gene that determines a particular trait or characteristic. A recessive allele is one of two or more alternative forms of a gene that may exist at a specific location on a chromosome.

A recessive allele is only expressed when it is present in two copies, meaning that an individual must inherit two copies of the recessive allele (one from each parent) for the trait associated with that allele to be expressed. If only one copy of the recessive allele is present, it will be masked by the dominant allele and the trait associated with the dominant allele will be expressed.

For example, consider the gene for hair color. Suppose that brown hair is dominant and that blonde hair is recessive. If an individual inherits one copy of the brown hair allele and one copy of the blonde hair allele, they will have brown hair since the brown hair allele is dominant. However, if an individual inherits two copies of the blonde hair allele, they will have blonde hair since the blonde hair allele is recessive and no dominant allele is present to mask it.

Overall, understanding the concept of a recessive allele is important because it helps explain patterns of inheritance and genetic conditions that are inherited in a recessive manner.

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