9610416 Reiss A central issue in biogographic research is the response of organisms to climatic changes. This research project addresses the question of the molecular genetic response of organisms to climate change. It is proposed that paleogenetics, the combination of paleontological and genetical techniques, will detect genetic changes over time and will facilitate the measurement of the force of climate change as an agent of natural selection. Th late Quaternary is a epoch that exhibits climatic warming and has a good fossil record. Especially well represented are species of Coleoptera (beetles), many of which are present in extant populations (Elias 1994). DNA sequence analysis on extant populations and fossil assemblages from this period of climate change will allow an assessment of the effect of climate change on the genetic constitution of natural populations. This rsearch will contribute to predictions regarding future global warning. This project will continue molecular biogeographic work on alpine-arctic beetle species begun as a postdoctoral research project (Reiss, unpublished data). Dr. A. Ashworth and Dr. D. Schwert (Quaternary Entomology Lab, Fargo, ND) will continue to collaborate and provide both extant and fossil specimens. Preliminary efforts at amplifying DNA from fossil chitin collected from bogs in the midwestern United States are encouraging, but are as of yet unconfirmed. The DNA in fossil chitin isolated from bogs may be sufficiently degraded to preclude extensive molecular analysis. However, a rich source of well-preserved fossil chitin is available from packrat midden researchers (Betancourt et al. 1990). Collaborators Dr. J. Betancourt (U.S. Geological Survey) and Dr. S. Elias (University of Colorado) have agreed to provide fossil beetle specimens sorted from packrat middens. This material is carbon-dated, and an independent assessment of the local ecossystem is available from studies of plant macrofossils present in the same midden. Packrat urine has dehydrating and antimicrobial activity, which preserves DNA structure. Other researchers have isolated plant and mammalian DN from middens. It is anticipated that arthropod DNA is also preserved. The first experiments will optimize DNA isolation and amplication techniques using an abundant fossil beetle species. Contemporary material is available to confirm that amplified DNA is from beetles, and not from other contaminating DNA sources. In order to detect genetic changes in the relatively short time span represented in the midden record, the mitochondrial DNA rgions amplified will be those that evolve quichly, such as the A+T rich region, which contains the origin of replication (Simon et al. 1994). Once molecular techniques are established, attention will be focused on species whose dispersal has been traced through time in the Chihuahuan Desert. A previously developed biogeographic model will be used as a guide (Elias 1992), and the molecular genetic data will be used to follow the movement of species through time. By comparing extant populations with fossil assemblages, the proportion of genetic variation represented in the fossil record will be calculated. Questios regarding the correlation of species richness and genetic variation will also be addressed. The tools to accurately calculate the microevolutionary rates of specific regions will be developed and used to detect changes in rate of response to climate change. Eventually, this data will be used to predict response of species to contemporary global change.
