Glossary

Glossary

Bias in gene retention

the retention of copies of genes after duplication is not random, relative to gene function or evolutionary rate. This bias can be a confounding factor in large scale analyses of paralogs: the function of duplicate genes in a genome results both from the bias in retention and from evolution after duplication.

Homologs

genes descending from a common ancestor.

In-paralogs

paralogs resulting from a duplication after a speciation event of reference.

Negative selection

selection that decreases the chance of fixation of a mutation because it is detrimental; it results in a decrease in the rate of evolution of selected mutations.

Neofunctionalization

the process in which one paralog gains a new function, which is selectively advantageous.

One-to-one orthologs

orthologs which are present in a single copy in each genome of interest.

Orthologs

homologs which have diverged since a speciation event.

Out-paralogs

paralogs resulting from a duplication before a speciation event of reference.

Paralogs

homologs which have diverged since a duplication event.

Positive selection

selection that increases the chance of fixation of a mutation because it is beneficial; it results in an increase in the rate of evolution of selected mutations.

Subfunctionalization

the process in which paralogs partition the ancestral function, so that each performs only part of this function. Subfunctionalization can happen by degenerating reciprocal mutations (DDC model), or by positive selection for specialization (escape from adaptive conflict).

Trends in Genetics

Volume 25, Issue 5, May 2009, Pages 210-216