How do mutations lead to new alleles?

Mutations lead to new alleles by altering the DNA sequence of a gene, creating a different version of that gene.

In more detail, mutations are changes that occur in the DNA sequence of a gene. These changes can happen spontaneously or can be induced by external factors such as radiation or chemicals. The DNA sequence of a gene determines the structure of the protein it codes for. Therefore, when a mutation alters this sequence, it can lead to the production of a different protein, or a protein that functions differently. This new version of the gene, resulting from the mutation, is what we refer to as a new allele.

There are several types of mutations that can lead to new alleles. These include point mutations, where a single base pair in the DNA sequence is changed; insertions, where extra base pairs are added to the sequence; and deletions, where base pairs are removed from the sequence. Each of these types of mutations can result in a different allele.

For example, consider a gene that codes for eye colour. If a mutation occurs in this gene, it could change the DNA sequence and therefore the protein that is produced. This could result in a different eye colour, and thus a new allele for eye colour would be created.

It's important to note that not all mutations result in new alleles. Some mutations may not change the protein that is produced, or they may not change it in a way that affects its function. These are known as silent mutations. However, when a mutation does result in a new allele, it can lead to variation within a population, which is a key driver of evolution.