Event Abstract

ANNOTATION OF THE NEUROENDOCRINE-ASSOCIATED GENES OF THE LAMPREY PETROMYZON MARINUS AND THE IMPLICATIONS FOR EVOLUTION OF VERTEBRATE GONADOTROPIN-RELEASING HORMONES

  • 1 University of New Hampshire, Center for Molecular and Comparative Endocrinology, United States
  • 2 University of Kentucky, Department of Biology, United States
  • 3 Michigan State University, Department of Fisheries and Wildlife, United States

The development of the hypothalamic-pituitary axis was a seminal event in the evolution of vertebrates. Study of the ancestral jawless vertebrates is key to understanding this event, with the gonadotropin-releasing hormones (GnRHs) deserving particular attention given their pivotal placement in the hierarchy of the neuroendocrine system. Previous data incorporating several lines of evidence showed all known vertebrate GnRHs were grouped into four paralogous lineages: GnRH 1, 2, 3 and 4; with proposed evolutionary paths. Using the currently available lamprey genome assembly, we have identified many neuroendocrine system genes and analyzed in greater detail the evolutionary history of the GnRHs based on the conserved syntenies between lamprey and gnathostomes. Our analysis corroborates recent views that GnRH3 was lost in the tetrapod lineage and did not arise in the teleost lineage as a result of a third round of whole genome duplication. With respect to the agnathans and GnRH, our analysis of the synteny agree with the previous proposal in that lamprey GnRH-I and –III resulted from a duplication event within the lamprey lineage. However, the data now suggest a substantially different view of the evolutionary history of the GnRH family in vertebrates. Significantly, the current evidence suggests that all of the genome duplication events that generated the different fish and tetrapod paralogous groups likely took place before the divergence of the ancestral agnathans and gnathostome lineages and that the type IV GnRHs in lamprey (GnRH-I and -III) share a more recent common ancestry with GnRH2 and 3. Given the single amino acid difference between lamprey GnRH-II and GnRH2 we propose that a GnRH2-like gene existed before the lamprey/gnathostome split and that paralogous genes (GnRH-I/III and GnRH 3) evolved divergent structure/function in lamprey and gnathostome lineages. The synteny analysis offers a new view on the evolution of the GnRHs.

Acknowledgements

Supported by NSF IOS-0849569, NH AES Hatch 332 and the Lamprey Genome Project Consortium.

Keywords: evolution, Genome, GnRH, Lamprey, neuroendocrine, Synteny

Conference: NASCE 2011: The inaugural meeting of the North American Society for Comparative Endocrinology, Ann Arbor, United States, 13 Jul - 16 Jul, 2011.

Presentation Type: Poster

Topic: Molecular evolution

Citation: Decatur WA, Smith JJ, Hall J, Li W and Sower SA (2011). ANNOTATION OF THE NEUROENDOCRINE-ASSOCIATED GENES OF THE LAMPREY PETROMYZON MARINUS AND THE IMPLICATIONS FOR EVOLUTION OF VERTEBRATE GONADOTROPIN-RELEASING HORMONES. Front. Endocrinol. Conference Abstract: NASCE 2011: The inaugural meeting of the North American Society for Comparative Endocrinology. doi: 10.3389/conf.fendo.2011.04.00124

Received: 22 Jul 2011; Published Online: 09 Aug 2011.

* Correspondence: Dr. Stacia A Sower, University of New Hampshire, Center for Molecular and Comparative Endocrinology, Durham, NH, 03824, United States, sasower@cisunix.unh.edu

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