FIGURE 7.

Gene synteny of the opioid (CRH/UCN) paralogon in the cyclostomes. The sea lamprey, Arctic lamprey, and hagfish homolog genome regions were compared. To highlight for potential gene shuffling/crossing-over events between the two lampreys and the two lampreys and hagfish, the sea lamprey genes that map in the same scaffold were represented by the same color. The exceptions are the CRH/UCN members which are represented by red-full boxes. Members of the same family in the sea lamprey genome or homologs in the other two cyclostome species are aligned. Gene chromosomal positions (Mb, below each gene) are shown. The sea lamprey genes are represented according to their position in the scaffolds and homologs in the Arctic lamprey and hagfish were positioned in relation to the sea lamprey genes. When possible different fragments of Arctic lamprey genome that possess a similar gene environment to a unique sea lamprey scaffold region were merged and this is marked by “//.” The hagfish CRH-like gene is dashed because this gene is not predicted in the species genome assembly. Tandem duplicate genes are represented by x2. Homologs for other lamprey CRH/UCN-like neighboring genes were found in the hagfish genome assembly but are not shown as they are located on multiple small scaffolds.