Fig. 1: Origins of U/V sex chromosomes in brown algae.
From: Origin and evolutionary trajectories of brown algal sex chromosomes
a, Macrosynteny plot comparing genomes of six dioicous (green), two monoicous (red), one dioecious (blue) and one outgroup species (yellow). The chromosomes were originally numbered by their physical size in the Ectocarpus v2 genome141. Note that the dioecious species F. serratus has a fully diploid life cycle (without gametophytes7). Syntenic blocks of the V sex chromosome are highlighted in red, with the emergence of U/V chromosomes shown in the phylogeny. Genome sizes are indicated in brackets. b, Microsynteny plot of V chromosomes in five dioicous species, highlighting the male sex-determining regions (blue) and the PARs (green). The PAR genes whose orthologues are found within the SDR of other species are highlighted in purple. c, Microsynteny plot of U chromosomes in two dioicous species, highlighting the female sex-determining regions (peach) and the PARs (green). The PAR genes whose orthologues are found within the SDR of other species are highlighted in purple. Note that the genome assemblies for C. linearis and S. ischiensis are not chromosome level, leading to a high number of contigs.
