An introduction to algal phylogeny and phylogenetic methods

Abstract

The algae are an assemblage of morphologically diverse, photosynthetic protists that are ubiquitous in distribution. The understanding of algal phylogeny has been revolutionized with molecular evolutionary methods. These analyses have shown that the algae are of a polyphyletic origin and diverge nearly simultaneously from each other in the crown group radiation (except euglenophytes). An interesting perspective on algal origin is gained by the analysis of plastid origin because many plastids (e.g., in cryptophytes, dinoflagellates, chlorarachniophytes, and euglenophytes) have arisen multiple, independent times through secondary endosymbioses. This chapter is an introduction to algal phylogeny and to the most common methods used in the construction of evolutionary trees. The subsequent 13 chapters in this book deal with specific aspects of the phylogeny of cyanobacteria (the primary source of the algal plastid), plastids and all the major algal lineages.