XSIQ
*

Biology - Gene drift

Gene drift

The possibility of losing alleles from the gene pool is of significance
for small populations why?

Random changes can have an effect on allele frequency too. In small
populations particularly, chance events can affect the frequency of
particular alleles. The change in frequency is random and unpredictable. In
some cases an allele can be eliminated or lost (0% frequency) from the gene
pool altogether. In some cases an allele may become fixed (100% frequency)
as the only allele for that gene in the gene pool.

This is of significance to survival of a species when only a few small
populations remain. Despite the efforts of conservationists, the species
may be in danger of extinction because certain 'favourable' alleles are
eliminated over successive generations and there is loss of genetic
diversity, that is, a loss of particular alleles of genes from the gene
pool.

The smaller the population the greater the statistical effect. In a large
population, random changes in allele frequency would have less impact on
the population as a whole.

Previous | Next