TY - JOUR T1 - Within-Arctic horizontal gene transfer as a driver of convergent evolution in distantly related microalgae JF - bioRxiv DO - 10.1101/2021.07.31.454568 SP - 2021.07.31.454568 AU - Richard G. Dorrell AU - Alan Kuo AU - Zoltan Füssy AU - Elisabeth Richardson AU - Asaf Salamov AU - Nikola Zarevski AU - Nastasia J. Freyria AU - Federico M. Ibarbalz AU - Jerry Jenkins AU - Juan Jose Pierella Karlusich AU - Andrei Stecca Steindorff AU - Robyn E. Edgar AU - Lori Handley AU - Kathleen Lail AU - Anna Lipzen AU - Vincent Lombard AU - John McFarlane AU - Charlotte Nef AU - Anna M.G. Novák Vanclová AU - Yi Peng AU - Chris Plott AU - Marianne Potvin AU - Fabio Rocha Jimenez Vieira AU - Kerrie Barry AU - Joel B. Dacks AU - Colomban de Vargas AU - Bernard Henrissat AU - Eric Pelletier AU - Jeremy Schmutz AU - Patrick Wincker AU - Chris Bowler AU - Igor V. Grigoriev AU - Connie Lovejoy Y1 - 2021/01/01 UR - http://biorxiv.org/content/early/2021/08/02/2021.07.31.454568.abstract N2 - The Arctic Ocean is being impacted by warming temperatures, increasing freshwater and highly variable ice conditions. The microalgal communities underpinning Arctic marine food webs, once thought to be dominated by diatoms, include a phylogenetically diverse range of small algal species, whose biology remains poorly understood. Here, we present genome sequences of a cryptomonad, a haptophyte, a chrysophyte, and a pelagophyte, isolated from the Arctic water column and ice. Comparing protein family distributions and sequence similarity across a densely-sampled set of algal genomes and transcriptomes, we note striking convergences in the biology of distantly related small Arctic algae, compared to non-Arctic relatives; although this convergence is largely exclusive of Arctic diatoms. Using high-throughput phylogenetic approaches, incorporating environmental sequence data from Tara Oceans, we demonstrate that this convergence was partly explained by horizontal gene transfers (HGT) between Arctic species, in over at least 30 other discrete gene families, and most notably in ice-binding domains (IBD). These Arctic-specific genes have been repeatedly transferred between Arctic algae, and are independent of equivalent HGTs in the Antarctic Southern Ocean. Our data provide insights into the specialized Arctic marine microbiome, and underlines the role of geographically-limited HGT as a driver of environmental adaptation in eukaryotic algae.Competing Interest StatementThe authors have declared no competing interest. ER -