(A) Example of part of a paralog cluster of bicycle genes from chromosome 7 of the H. cornu genome, illustrating abundance of small exons in each gene.
(B) Distribution of singleton bicycle genes and paralog clusters in the H. cornu genome. Number of genes per cluster and genomic range is indicating by height and width, respectively, of blue bars above chromosomes. Histogram of number of bicycle genes per paralog cluster is shown in inset.
(C) Number of exons per gene versus median exon size for H. cornu bicycle (blue) and non-bicycle (red) genes. Bicycle genes possess an unusually large number of unusually small exons.
(D) Maximum likelihood phylogenetic tree of H. cornu bicycle gene amino acid sequences reveals extensive sequence divergence of bicycle genes.