Abstract
The role and extent of horizontal gene transfer (HGT) in eukaryotes are hotly disputed topics that impact our understanding of the origin of metabolic processes and the role of organelles in cellular evolution. We addressed this issue by analyzing 10 novel Cyanidiales genomes and determined that 1% of their gene inventory is HGT-derived. Numerous HGT candidates share a close phylogenetic relationship with prokaryotes that live in similar habitats as the Cyanidiales and encode functions related to polyextremophily. HGT candidates differ from native genes in GC-content, number of splice sites, and gene expression. HGT candidates are more prone to loss, which may explain the absence of a eukaryotic pan-genome. Therefore, the lack of a pan-genome and cumulative effects fail to provide substantive arguments against our hypothesis of recurring HGT followed by differential loss in eukaryotes. The maintenance of 1% HGTs, even under selection for genome reduction, underlines the importance of non-endosymbiosis related foreign gene acquisition.
Highlights
Eukaryotes transmit their nuclear and organellar genomes from one generation to the in a vertical manner
In spite of massive gene losses observed in the Cyanidiales (Qiu et al, 2015), these results corroborate previous observations that genome reduction has had a minor influence on the core eukaryotic gene inventory in free-living organisms (Qiu et al, 2016)
Pulsed-field gel electrophoresis indicates that G. sulphuraria 074W has approximately 42 chromosomes that are between 100 kbp and 1 Mbp in size (Weber, 2007)
Summary
Eukaryotes transmit their nuclear and organellar genomes from one generation to the in a vertical manner. A pan-genome comprises all genes shared by any defined phylogenetic clade and includes the so-called core (shared) genes associated with central metabolic processes, dispensable genes present in a subset of lineages often associated with the origin of adaptive traits, and lineage-specific genes (Vernikos et al, 2015). This phenomenon is so pervasive that it has been questioned whether prokaryotic genealogies can be reconstructed with any confidence using standard phylogenetic methods (Philippe and Douady, 2003; Doolittle and Brunet, 2016). As eukaryote genome sequencing has advanced, an increasing body of data has pointed towards
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
