Question #f9c90

A trait is an observable physical characteristic, such as blue eyes, blond hair, etc.

Genes are specific sections of DNA that code for your traits. Thus, your genes determine your traits.

An allele is a specific version of a gene. Most genes have only two alleles (two versions), but some have multiple alleles.

Let's say the gene that codes for eye color has two alleles: the dominant allele #"B"#, which represents brown eyes, and the recessive allele #"b"#, which represents blue eyes.

Each of your parents donates one allele to you. These two alleles form your genotype. If you had the genotype #"BB"#, you would have brown eyes. If you had the genotype #"Bb"#, you would also have brown eyes, since the dominant #"B"# "dominates" and covers up the recessive #"b"#. Finally, if you had the genotype #"bb"#, you would have blue eyes.

To recap, alleles are different versions of a gene. #"B"# and #"b"# are both alleles; however, #"B"# is the dominant allele and represents brown eyes, while #"b"# is the recessive allele and represents blue eyes. The genotype you have determines the trait you will exhibit.