Mitochondrial Control-Region Sequences in Two Shorebird Species, the Turnstone and the Dunlin, and Their Utility in Population Genetic Studies

Because of its rapid rate of sequence evolution, al most strictly maternal mode of inheritance, and lack of recombination, mitochondrial DNA (mtDNA) is the molecule of choice both for studies of intraspecific sequence divergence (Wilson et al. 1985; but see Gyllensten et al. I99 1) and for constructing gene trees within and among related species (Avise et al. 1987; Avise 1989). In addition, different regions of the molecule evolve at different rates, and thus an appropriate region can be selected to resolve the phylogenetic relatedness of the particular maternal lineages under study. The control region (or D-loop region) contains the heavy (H)-strand origin of replication, as well as the promoters of transcription for both strands (Clayton 1982, 1984). It evolves three to five times faster than the remainder of the mitochondrial genome ( Aquadro and Greenberg 1983; Cann et al. 1984; but see Hoelzel et al. 199 1 ), presumably because of lack of coding constraints. [