Conservation Genetics: Techniques and Fundamentals

Abstract

Conservation genetics utilizes the tools and concepts of genetics and applies them to problems in conservation biology. For example, molecular genetic techniques, such as protein electrophoresis, and analysis of mitochondrial DNA and highly variable nuclear genes (including DNA fingerprinting), have been important in documenting the extent and pattern of genetic variation in endangered species. We review these techniques and their advantages and disadvantages, and give examples of their application to endangered species. For captive animal populations, pedigree analysis has become the basic approach to evaluate breeding priority of particular individuals. Several pedigree analysis techniques are commonly used, but peeling and gene dropping give the most information. We compared these techniques and illustrate their value with applications to the Guam Rail, Przewalski's horse, and other endangered captive animals. The rationale for much conservation genetic interpretation is base in evolutionary genetics. We discuss the avoidance of inbreeding depression and the maintenance of genetic variation-both primary conservation genetic goals-from this perspective. In addition, we suggest aspects of these factors that deserve greater attention in their overall application to conservation planning. Finally, we briefly mention three evolutionary topics-the relationship of heterozygosity and fitness, population bottlenecks, and outbreeding depression-that have implications for conservation genetics. Although simple interpretation in these areas is appealing, we feel that because they are only generally understood and often quite controversial, their application to endangered-species management should be carefully evaluated and monitored.

GENETIC VARIATION IN INBREEDING DEPRESSION IN THE RED FLOUR BEETLE TRIBOLIUM CASTANEUM

“…This is es pecially true if strategies to minimize inbreeding conflict with strategies invoked to manage for other genetic or nongenetic threats. In particular, a primary aim of genetic management of endangered species is preservation of founder allele rep resentation (e.g., Hedrick and Miller 1992). A subdivided population may retain more genetic variability in the form of allelic diversity than a single panmictic population (Rob ertson 1964).…”

Purging inbreeding depression and the probability of extinction: full-sib mating

“…The general genetic goals of captive breeding of endangered species are to avoid inbreeding depression and to maintain genetic variation (Hedrick & Miller, 1992). In an effort to provide the basis for the size of a captive population which would not experience detrimental inbreeding effects on fitness, Franklin (1980) suggested as guidance that 'animal breeders accept inbreeding coefficients as high as a one per cent increase per generation (i.e.…”

Structure and amount of genetic variation at minisatellite loci within the subspecies complex of Phoca vitulina (the harbour seal)

“…Genetic variation is considered to be of major importance for the adaptability of populations and species to changing and deteriorating environments (SchonewaldCox et al, 1983;Lynch & Lande, 1993). Moreover, loss of genetic variation and an increase in homozygosity caused by genetic drift and inbreeding can result in a significant decrease in fitness (inbreeding depression) and consequently to an elevated risk of extinction (Frankel & Soulé, 1981;Schonewald-Cox et a!., 1983;Soulé, 1987;Hedrick & Miller, 1992;Bijisma et a!., 1994). An often cited example of a species that possibly has passed through several bottlenecks and suffers from an exceptional loss of genetic variation is the southern African cheetah (O'Brien et a!., 1987).…”