Genomic and phylogenetic assessment of sea lamprey (Petromyzon marinus) Hox genes and analysis of Hox genes in association with myomeres across multiple lamprey genera

Abstract

Lampreys are an important model for the study of early vertebrate development due to their unique evolutionary position as one of only two extant jawless vertebrates. In this study, 12 new putative Hox gene fragments were identified within the recently available Petromyzon marinus (sea lamprey) genome. These and the other previously-identified Hox genes were analyzed phylogenetically, which enabled the assignment of many of the new sequences to distinct paralogous gene clusters and showed distinctions between gnathostome and lamprey Hox sequences. An examination of Hox genes in other lamprey species was conducted using genomic PCR-based detection methods and identified 26 putative Hox gene homeobox fragments from multiple Hox genes across nine lamprey species. A study of Hox10 coding sequences in different lamprey species failed to find any correlation with variable numbers of trunk myomeres in lampreys, which suggests that other sequences or factors regulate the number of myomeres in different species.