Abstract # 217:

Scheduled for Saturday, August 19, 2006 09:30 AM-09:45 AM: Session 20 (Regency East #3) Oral Presentation

Mitochondrial sequence diversity of the southernmost extant New World monkey, Alouatta caraya$

M. S. Ascunce1,2, E. Hasson1, G. Zunino3 and M. D. Mudry1
1Universidad de Buenos Aires, Ciudad Universitaria, Pab: 2, 4to.Piso, Lab: 46, Buenos Aires C1428EHA, Argentina, 2University of Florida, Genetic Analysis Laboratory (ICBR), 421 Carr Hall, PO Box 118525, Gainesville, FL 32611-8525, USA, 3Estación Biológica de Usos Multiples (EBCo), Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”, Ruta Provincial 8, San Cayetano, Corrientes, 3401, Argentina
     Phylogeographic studies can provide a powerful tool to assess the significance of historical events in terms of the genetic diversity of populations, by analyzing the geographic and temporal distribution of lineages. The black and gold howler monkey, Alouatta caraya, has the southernmost distribution of any Neotropical primate and may be an interesting model for the examination of genetic footprints in postglacial population expansions. Mitochondrial sequence variation was analyzed in A. caraya to investigate genealogical relationships among populations and to evaluate the effect of post-glacial climatic change and forest expansion on the demographic history of this species. Seventy-three specimens were sampled from six localities, resulting in 34 control region haplotypes. Fu’s test (F = -12.137; p < 0.001) allowed estimation of the time of demographic expansion, which occurred 7,000-15,500 years ago. These dates correspond to the end of the Pleistocene glaciations and the beginning of global warming. Both network and neighbor-joining analyses of the haplotypes revealed the presence of two sympatric clades. This pattern may have arisen as a consequence of secondary contact between previously isolated populations, of balancing selection, or of gene flow among populations with large effective size. Further analysis of our data indicated that A. caraya went through a severe bottleneck, or had a low historical effective population size. In either case A. caraya experienced a relaxation of selection due to population expansion.