Comparative and Phylogenetic Analysis of Lipid Gene Families in Four Haptophyte Species

The purpose of this research is to provide insight into protein families that might be linked into alkenones metabolism in E. Huxleyi, G. oceanica and I. Galbana species. Alkenonesare a unique long-chain of (C37-C39) unsaturated ethyl and methyl ketones that are synthesized by limited number of Haptophyte algae. In this study we used the threehaptophyte species that synthesize alkenone E. Huxleyi, G. oceanica and I. Galbana species and Chrysochromulina that does not produce alkenones. The protein sequencesfor the four haptophyte species were run against the EggNOG database to identify their protein families. The provided E. huxleyi lipid proteins from KEGG pathway were used todetermine the lipid protein families in E. Huxleyi, and further across the other species. 29 lipid protein families were identified to be shared by E. Huxleyi, G. oceanica and I.Galbana, but not presented as top family for any Chrysochromulina protein. Next, we identified and extracted the most common PFAM domain for each of the 29 families.Phylogenetic trees were then constructed for the 29 lipid protein families by aligning the extracted protein domain sequences, to provide insight into the sequences similarity andevolutionary relationship among the species. Out of 29 phylogenetic trees 14 phylogenetic trees showed the three sister species in one clade. We reconstructed thephylogenetic trees for the 14 families using BAST application and EggNOG pipeline to compare and confirm the phylogenetic trees. Out of 14 phylogenetic trees there are 6lipid protein families that their phylogenetic trees demonstrated the expected result, which means the E. Huxleyi, G. oceanica and I. Galbana are in one clade and Chrysochromulina out of the clade but close to the three species clade. These are 6 lipid protein families that can be further studied to determine their involvement withalkenones production in E. Huxleyi, G. oceanica and I. Galbana.