This week’s Wednesday wiki page is on Coalescent Theory:
coalescent theory states that all genes or alleles in a given population are ultimately inherited from a single ancestor shared by all members of the population, known as the most recent common ancestor. If the inheritance relationships are written in the form of a phylogenetic tree, termed a gene genealogy, the gene or allele of interest is said to undergo coalescence to the common ancestor (sometimes termed the concestor to emphasize the coalescent relationship).