Quantitative and Molecular Genetic Variation in Captive Cotton-Top Tamarins (Saguinus oedipus)

Most genetic surveys of captive and endangered populations are carried out with single gene characters bearing no direct relationship to life history or other features for which genetic variation needs to be maintained. Quantitative genetic estimates of heritable variation for life-history traits may be a more direct and appropriate measure of genetic variation for some conservation purposes. Furthermore, recent theoretical and empirical results indicate that genetic variation measured on these two levels may not be concordant. We analyzed heterozygosity at 41 allozyme loci and heritability for body weight in captive cotton-top tamarins ( Saguinus oedipus ) from the Marmoset Research Center of the Oak Ridge Associated Universities in order to compare these two levels of genetic variation. Cotton-top tamarins are a highly endangered species native to Colombia. Many animals currently reside in research facilities and zoological parks. A total of 106 animals were used in the isozyme survey, while data on 364 animals contributed to the quantitative genetic study of body weight. We found a very low average heterozygosity ( H = 1%) for this colony. Body weight was moderately and significantly heritable ( h ² = 35%). This heritability is within the normal range for natural animal populations. The finding of biologically significant levels of heritability in a population with abnormally low allozyme heterozygosity illustrates the point that low levels of allozyme heterozygosity should not be taken as an indication of overall lack of genetic variation in important quantitative characters such as life-history traits. Genetic variation required for adaptation of species to future environmental challenges can exist despite low levels of enzyme heterozygosity.     

Ecological impacts and management strategies for western larch in the face of climate-change

Approximately 185,000 forest inventory and ecological plots from both USA and Canada were used to predict the contemporary distribution of western larch (Larix occidentalis Nutt.) from climate variables. The random forests algorithm, using an 8-variable model, produced an overall error rate of about 2.9 %, nearly all of which consisted of predicting presence at locations where the species was absent. Genetic variation among 143 populations within western larch’s natural distribution was predicted from multiple regression models using variables describing the climate of the seed source as predictors and response data from two separate genetic tests: 1) 15-year height at a field site in British Columbia, Canada, and, 2) two principal components of 8 variables describing growth, disease tolerance, and phenology of 6-year-old trees in a test in Idaho, USA. Presence and absence of the species and genetic variation within the species were projected into future climates provided by three General Circulation Models and two scenarios. Although the projections described pronounced impacts on the species and its populations, concurrence among the six projections pinpointed areas where the probability would be high that the future climate would be suitable for western larch. Concurrence among projections also was used to locate those sources of seed that should be best attuned genetically to future climates. The procedures outline a logical approach for developing management strategies for accommodating climate-change while taking into account the variability imposed by the differences among climatic estimates.     

Environmental monitoring at Hanford,Washington, USA: A brief site history and summary of recent results

Nuclear and nonnuclear industrial and research activities have been conducted on the Hanford reservation since 1943. Materials originating from these activities may enter the surrounding environment through releases of airborne and liquid effluents and solid wastes. Concern about the environmental effects of these releases has evolved over the past four decades into a comprehensive onsite and offsite monitoring program. Today, environmental monitoring to assess potential impacts of released materials includes field sampling and chemical and physical analyses of air, ground and surface water, fish and wildlife, soil, vegetation, and foodstuffs. This paper reviews the history of Hanford operations and summarizes the current environmental monitoring program and its major findings. Mathematical models based on monitoring data show that radiation doses to people living near the Hanford site are well below existing regulatory standards. Only trace amounts of radionuclides from Hanford have been detected in the offsite environment.