Rapid concerted evolution in animal mitochondrial DNA

Abstract

Recombinational genetic processes are thought to be rare in the uniparentally inherited mitochondrial (mt) DNA molecules of vertebrates and other animals. Here, however, we document extremely rapid concerted microevolution, probably mediated by frequent gene conversion events, of duplicated sequences in the mtDNA control region of mangrove killifishes (Kryptolebias marmoratus). In local populations, genetic distances between paralogous loci within an individual were typically smaller (and often zero) than those between orthologous loci in different specimens. These findings call for the recognition of concerted evolution as a microevolutionary process and gene conversion as a likely recombinational force in animal mtDNA. The previously unsuspected power of these molecular phenomena could greatly impact mtDNA dynamics within germ cell lineages and in local animal populations.

Figure 1

Haplotype network of CR1 and CR2 sequences. The network is constructed using the method of Templeton et al. (1992) implemented in software TSC v. 1.21 (Clement et al. 2000). Haplotypes and their designations are shown in table 1. Each connecting line represents a single mutation; solid dots are inferred haplotypes.