Mitochondrial genomes of Isochrysis and Pavlova reveal hidden gain and loss of genes in Haptophytes

Abstract

Haptophytes is one of distinct and interesting lineage in the photosynthetic eukaryote evolution via serial endosymbiosis. Emiliania, Isochrysis, Pavlova and Phaeocystis are well-known and important primary producers in ocean ecosystem. Despite evolutionary and ecological importance of the lineage, genetic and species diversity with evolutionary history are not fully understand yet. In present study, we assembled nine new mitochondrial genomes (mtDNA) from Isochrysis and Pavlova, i.e., 26,188 ~ 41,838 bp in total length. The dataset encompassed 15-22 protein coding genes of all available haptophytes (14 taxa), including Emiliania hyxleyi, Chrysochromulina sp. NIES 1333 and Chrysochromulina sp. CCMP 291, and Pavlova lutheri CCMP 1325. The best phylogeny reveals a monophyly of Haptophyta, basal position of Pavlova, and multiple gain and loss of CDS in each clade.