NSF Award
0110540
0110540<br/>Langeland<br/><br/>The overall goal of the proposed study is to take advantage of the unique<br/>phylogenetic position of the lamprey, Petromyzon marinus, to address<br/>fundamental issues of developmental and molecular evolution in the<br/>vertebrate lineage. Lampreys are the simplest extant vertebrates, situated<br/>phylogenetically between the cephalochordates (represented by amphioxus)<br/>and the gnathostomes (represented by mammals, birds, reptiles, amphibians,<br/>and fish). Morphologically, lampreys share several characteristics with<br/>their gnathostome sister group, including multiple brain divisions, neural<br/>crest and its derivatives, neurogenic placodes, pharyngeal arches, and a<br/>cartilaginous endoskeleton, but they lack jaws and paired appendages and<br/>retain a relatively simple axial morphology. Genetically, lampreys also<br/>appear to be less complex than gnathostomes, having undergone fewer<br/>duplications of developmental regulatory genes. Lampreys are thus a<br/>perfect system with which to investigate developmental and molecular events<br/>associated with early vertebrate evolution. Dr. Langeland has led in<br/>recent efforts to establish lampreys as a viable system for comparative<br/>developmental genetics. There are two basic thrusts to this proposal: 1)<br/>to use gene expression studies in lamprey embryos to investigate<br/>fundamental aspects of the evolution of vertebrate head patterning, and 2)<br/>to use gene phylogeny studies to test whether duplications of select<br/>regulatory genes accompanied vertebrate origins. The Langeland laboratory<br/>will clone and characterize members of the goosecoid, Emx, and snail/Slug<br/>gene families in P. marinus. These genes are excellent markers for three<br/>key developmental innovations that accompanied vertebrate origins: the<br/>establishment of the head organizer, the elaboration of rostral brain<br/>patterning, and the acquisition and diversification of cephalic neural<br/>crest. Comparative expression analyses of these genes during lamprey<br/>embryogenesis will allow more precise reconstruction of developmental<br/>events associated with vertebrate origins.<br/>In addition, determination of the copy number of these genes in lampreys,<br/>and analysis of their phylogenetic relationships with their gnathostome and<br/>protochordate homologs, will provide important evidence concerning whether<br/>widespread gene duplications, or even whole genome duplication, facilitated<br/>vertebrate origins. This research will take place at a four-year<br/>undergraduate liberal arts college. Extensive involvement of<br/>undergraduates in all phases of the project will help maintain the strong<br/>record of the host institution and of the principal investigator in<br/>integrating research with teaching, and in preparing future Ph.D.s in the<br/>life sciences.
