MUTATIONS & ALLELE FREQUENCY

==Mutations & Allele Frequency== [image:http://i.imgur.com/JUXlPwo.jpg?2] '''Mutations are any permanent changes to the sequence of bases in an individual’s genome.''' Mutations are the source of new alleles (and thus ultimately the source of all variation). This means that they can introduce new alleles into a population. In the population depicted below one individual carries a new recessive allele. If the mutation is somatic or is disadvantageous in some way (reduces fitness), then the allele may simply be lost from the population. However, if the new allele conveys some adaptive / competitive advantage over the other alleles (it increases fitness) the frequency of the new allele will increase. [image:http://i.imgur.com/KLTOeTB.png?1] This graph depicts how a mutant allele (blue) that conveys some competitive advantage increases over time. One of the other alleles decreases and is eventually lost. Mutations will often produce neutral alleles that are neither advantageous nor disadvantageous. However, if environmental conditions change the new allele might convey some adaptive advantage and help ensure the survival of the species. This is why genetic variation (having a variety of alleles) is so important.