Large sequence divergence among mitochondrial DNA genotypes within populations of east African black-backed jackals

Abstract

In discussions about the relative rate of molecular evolution, intraspecific variability in rate is rarely considered. An underlying assumption is that intraspecific sequence differences are small, and thus variations in rate would be difficult to detect or would not affect comparisons among distantly related taxa. However, several studies on mammalian mitochondrial DNA (mtDNA) have revealed considerable intraspecific sequence divergence. In this report, we test for differences in the rate of intraspecific evolution by comparing mtDNA sequences, as inferred from restriction site polymorphisms and direct sequencing, between mtDNA genotypes of the eastern African black-backed jackal, Canis mesomelas elongae, and those of two other sympatric jackal species. Our results are unusual for several reasons. First, mtDNA sequence divergence within several contiguous black-backed jackal populations is large (8.0%). Previous intraspecific studies of terrestrial mammals have generally found values of