We continue our work aimed at understanding the evolutionary forces shaping the patterns of intra and inter-islands differentiation in Giant Galapagos tortoises. We have emphasized the incorporation of DNA data from extinct populations into the previously produced molecular phylogeny to aid in understanding the evolutionary history of these species and help in the conservation efforts to preserve them. Highlights from this work include: 1) the recent discovery of genes from an extinct species of tortoise, from the island of Floreana, in living tortoises from a different population, raising the possibility of rescuing this lineage from extinction, 2) the discovery of a new species of Galapagos tortoises in the most populated island of the archipelago, 3) understanding of the complex patterns of relatedness among tortoise populations on the southern part of the island of Isabela, 4) using the molecular diagnostic tools we have developed to manage ongoing breeding programs, and identify the evolutionary origin of captive individuals, 5) found living relatives for Lonesome George the last tortoises from the species, G. abingdoni, from the island of Pinta.
In recent years we've collaborated with Holly Rushmeier (Dept. of Computer Science, Yale University) to develop 3D methods to reconstruct the form of organisms in field conditions. We are using this method for 3D reconstruction of the carapace of Giant Galapagos tortoises for morphometric analyses.
We have developed molecular markers for nuclear and mtDNA region for this species and almost completed the genetic screen of 600+ samples collected in our 2004 field season. In multiple populations we have compared the genetic make-up of samples before and after a severe oil-spill in 2001 and before and after a severe El Nino event (19) to evaluate the impact of environmental or human induced stress (>60% mortality in the populations affected by the spill; 90% mortality rates for some populations after the 1985 El Nino year) on patterns and levels of genetic diversity. In parallel to the development of neutral DNA markers we are also engaged in developing non-neutral markers associated with the Major Histocompatability Loci (MHC). These genes are traditionally associated with the capacity of organisms to respond to environmental changes or stress. We are also completing a detailed metapopulation study of the iguanas from the island of Santa Fe to obtain baseline data for paternity and demographic studies to associate with ongoing behavioral work on this population carried out by Dr. Martin Wikelski and his lab at the Max Planck Institute, Germany. Scott Glaberman is the current member of the lab involved in this work. Past lab members involved with the project are Sebastian Steinfartz and Deborah Lantenbecq (University of Mons-Hainaut, Belgium).
For the past few years we have been involved with several research projects aimed at understanding the evolutionary relationships of tortoises from the Indian Ocean, including extant and extinct species. Our work has focused on endangered Madagascar tortoises and the Giant Aldabra tortoise.
Past lab members involved with the project are: Claudio Ciofi (Un. of Florence, Italy), Oliver Balmer and Eric Palkovacs.
The Amur Tiger, Panthera tigris altaica, is a rare subspecies of tiger. Also known as the Siberian, Korean, Manchurian, or North China Tiger, and is critically endangered. An initial survey of mtDNA levels of genetic diversity in the only wild population of this species was conducted by Michael Russello. This was followed by a a screen of microsatellite variation and the development of a molecular test to identify sex from scats. We have also screened for variation in the captive population, since our preliminary results suggest that this population harbors more genetic variation than the wild one. Additional collaborators for this project include: Dale Miquelle (WCS Russia program), Philippe Henry, Kathy Traylor-Holzer (AZA Tiger Regional Studbook Keeper) and several Yale undergraduates.
Russello, MA, E. Gladyshev, D. Miquelle, and A. CACCONE. 2004. Potential genetic consequences of a recent bottleneck in the Amur tiger of the Russian Far East. Conservation Genetics 5:707-713.
Henry, P., D. Miquelle, T. Sugimoto, A. CACCONE, M.A. Russello. Conservation genetics of Amur Tigers (Panthera tigris altaica): population structure in the Russian Far East and representation in captivity. In prep.