Phylogeny and phylogeography of Porites and Siderastrea (Scleractinia: Cnidaria) species in the Caribbean and Eastern Pacific; based on the nuclear ribosomal ITS region.

摘要

This study explores the ITS region (ITS-1-5.8S-ITS-2) as a genetic marker in two prominent Scleractinian genera: Porites and Siderastrea, emphasizing the continuum between population genetics and phylogenetics. Chapter I is a review and introduction. Chapter II addresses widely-cited potential problems with the ITS region (Intra-individual heterogeneity and alignment gaps), and demonstrates how they can actually be informative. Chapter III investigates a putative cryptic species; Porites lobata-Panama , and examines the genetic structure and morphometric variability in P. lobata samples collected from the Galápagos, Easter Island, Tahiti, Fiji, Rarotonga, and Australia. Chapter IV examines shared ITS haplotypes in S. glynni and S. siderea , indicating that S. glynni originated either from a recent passage through the Panamá canal, or through an ancient (1–3mya) vicariant event. Both hypotheses have important implications for the evolution of the ITS region. Chapter V is a summary of the major conclusions.