Fig. 1.From: The X chromosome of the German cockroach, Blattella germanica, is homologous to a fly X chromosome despite 400 million years divergenceInsect phylogeny and sex chromosomes. Evolutionary relationships and sex chromosome karyotypes of major insect groups. The phylogenetic topology and time to common ancestor are shown [17], but the relative branch lengths are not drawn to scale. Information on insect sex chromosomes and sex determination are reviewed elsewhere [2, 3, 13, 16, 18]Back to article page