What is the meaning of an allele?

An allele is the form in which a gene for a trait can occur.

Explanation:

In all animal cells, one gene is inherited from each other. These two genes are called alleles. Alleles can also be referred to as a genetic sequence.

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explanation:

the fossil record extends back to a dog-like ancestor some 55 million years ago, which gave rise to the first horse-like species 55 to 42 million years ago in the genus eohippus.