Coalescent Effective Size
According to the neutral theory of molecular evolution, a neutral allele remains in a population for Ne generations, where Ne is the effective population size. An idealised diploid population with have a pairwise nucleotide diversity equal to 4Ne, where is the mutation rate. The sojourn effective population size can therefore be estimated empirically by dividing the nucleotide diversity by the mutation rate.
The coalescent effective size may have little relationship to the number of individuals physically present in a population. Measured coalescent effective population sizes vary between genes in the same population, being low in genome areas of low recombination and high in genome areas of high recombination. Sojourn times are proportional to N in neutral theory, but for alleles under selection, sojourn times are proportional to log(N). Genetic hitchhiking can cause neutral mutations to have sojourn times proportional to log(N): this may explain the relationship between measured effective population size and the local recombination rate.
Read more about this topic: Effective Population Size
Famous quotes containing the words effective and/or size:
“The message you give your children when you discipline with love is “I care too much about you to let you misbehave. I care enough about you that I’m willing to spend time and effort to help you learn what is appropriate.” All children need the security and stability of food, shelter, love, and protection, but unless they also receive effective and appropriate discipline, they won’t feel secure.”
—Stephanie Marston (20th century)
“For truly I tell you, if you have faith the size of a mustard seed, you will say to this mountain, ‘Move from here to there,’ and it will move; and nothing will be impossible for you.”
—Bible: New Testament, Matthew 17:20.