Fig. 1.

Genome compaction features. (A) Chromosome regions assembled with physical links and genetic markers. The location of TEs is indicated with horizontal lines (lines on the left sides, DNA transposons; lines on right sides, short lines for long terminal repeat–retrotransposons and long lines for long interspersed elements). (B) Distribution of gene models over 10% abundance classes of intron size and upstream intergenic distance for 8812 nonoperon genes (left) and for 189 developmentally regulated genes, mainly transcription factors (right). (C) Conserved elements revealed in genome alignments of Atlantic and Pacific ocean populations of O. dioica:density of conserved blocks (top), gene annotation (middle), and perfectly conserved elements >100 bp (bottom gray line) (blue, Norway versus northwest America; red, Norway versus Japan). (D) Giant Y genes and their testis expression revealed by reverse transcription polymerase chain reaction and in situ hybridization. hpf, hours post fertilization; ctrl, control. The arrowhead indicates the giant gene expression product.