Fig. 1

Presence, location and characteristics of sex-linked, protein-coding genes and their pseudoautosomal region (PAR) and autosomal orthologs in seven brown algal species. Gene names are based on the Ectocarpus sp. annotation. For genes that were not annotated in the S. japonica reference genome [29], we used an abbreviation based on the Ectocarpus sp. gene (for instance, SJ-13_001840 corresponds to the ortholog of Ec-13_001840). Pseudogenes that are part of gametologue pairs are represented in italics. The presence of a male or female sex-linked gene in a given species is indicated by a blue or pink circle, respectively. Absence of a gene is indicated by a minus sign. Dark green circles indicate genes located in the PAR, light green circles represent either a PAR or an autosomal location. Grey circles indicate that the genomic location of a gene is unclear. Green circles with an R indicate retrogenes. The green circle with a P indicates a pseudoretrogene. The deduced history of each group of genes is shown to the left and the arguments on which the decision was based for each gene or gametologue pair are indicated with a cross to the right. *Blast results were ambiguous for this gene so orthology was determined by phylogeny; **we cannot totally exclude a scenario where these genes entered the SDR after the split of the Laminariales and Ectocarpales lineages. E. sp, Ectocarpus sp.; E. sil, E. siliculosus; E. fasc, E. fasciculatus; S. lom, S. lomentaria; S. jap, S. japonica; M. pyr, M. pyrifera ; U. pin, U. pinnatifida