General-use polymerase chain reaction primers for amplification and direct sequencing of enolase, a single-copy nuclear gene, from different animal phyla

In contrast to mitochondrial DNA, remarkably few general-use primer sets are available for single-copy nuclear genes across animal phyla. Here, we present a primer set that yields a c. 364-bp coding fragment of the metabolic gene enolase, which includes an intron in some taxa. In species where introns are absent or have few insertions/deletions, the amplified fragment can be sequenced directly for phylogenetic or population analysis. Between-species variation in the coding region occurs widely at third codon positions, even between closely related taxa, making the fragment useful for species-level systematics. In low gene-flow species, the primers may also be of use for population genetics, as intraspecific polymorphisms occur at several silent positions in the taxa examined.