Development of Contemporary Genomics Resources for Conservation and Biological Studies of Iguanas
The green anole lizard Anolis carolinensis was recently chosen to be the first species of reptile for whole genome sequencing. This species was selected because it has long been a model system for neurobiology, endocrinology, and evolutionary ecology. The availability of a genome sequence will not only identify every gene present in the species but will assist in determining the role played by natural selection in molding the genetic architecture of populations by evaluating genotype-phenotype relationships. This is a significant development over presently available resources, where most molecular genetic studies of reptiles have been limited to mitochondrial DNA (mtDNA) and simple sequence nuclear repeats known as microsatellites. A genome sequence of the green anole will provide the fundamental genomic reagents needed to develop similar resources for other species of reptiles.
One group of reptiles of particular interest for conservation biology to the Zoological Society of San Diego includes Caribbean iguanas and rock iguanas. The common iguana Iguana iguana has been successfully out-competing and potentially introducing genes into populations of the endangered Lesser Antillean iguana Iguana delicatissima. The eight species and 13 subspecies of rock iguanas (genus Cyclura) have very restricted geographic distributions, and represent some of the most endangered vertebrates in the world;, population estimates of certain species are 200 individuals or less.
The Genetics Division at CRES has received a unique invitation from the Broad Institute of Massachusetts Institute of Technology (MIT) and Harvard University to participate in the sequencing of the green anole genome. Dr. Kristen Lindblad-Toh of MIT has requested that fluorescence in situ hybridization (FISH) be carried out to anole chromosomes in order to anchor the sequenced contigs. FISH is currently being established at CRES by Dr. William Modi to assist in the identification of mutations responsible for chondrodystrophy in the California condor. The advantage to CRES of a contractual agreement with MIT will be to utilize the anole biological resources to facilitate the development of a genome toolkit for endangered iguanas. Genomic information for iguanas will be used in conservation genetics to identify genetic diversity among founders, to determine parentage among juveniles of unknown kinship, for individual recognition, and to identify genes responsible for specific phenotypes.
