All extant copies of a gene eventually coalesce; this occurs because

A) a particular allele becomes fixed in the population.
B) all extant genes coalesce at the same time in the same individuals.
C) the rate of coalescence speeds up as a population increases in size.
D) the original population consisted of only a single individual with the ancestral allele.

Gene Coalesce

A concept in molecular genetics where different alleles at a gene locus in different lineages trace back to a single ancestral allele.

Allele Fixed

The situation in a population where all members carry the same allele of a particular gene, leading to the lack of genetic variation for that gene locus.

Population Size

The total number of individuals within a defined area at a given time.