Mary Ashley, Systematist, Department of Biological Science, University of Illinois at Chicago
FINDING FAMILIES IN THE FIELD: MOLECULAR METHODS FOR STUDYING BREEDING AND BEHAVIOR
In many cases, geneticists may best be able to contribute to conservation and management of threatened species by providing new information on the basic biology of target species. Information on demography, effective population sizes, breeding, and dispersal are needed to develop management strategies, but such information is often difficult to obtain in field studies. Molecular approaches, specifically DNA microsatellite analysis of samples collected noninvasively or nondestructively, can be used to infer familial relationships in the field (parents and siblings). Once established, these relationships can be used to address a variety of issues relevant to conservation. Paternity assignment for chimpanzees included in a long-term behavioral study at Gombe, for example, provides information on the frequency of extra-group paternity and the effectiveness of behavioral avoidance of inbreeding. Additional examples involving extensive field collection combined with molecular identification of sibling groups will be presented, and their relevance for conservation discussed. This approach can be successfully used to gather information about a species at risk or invasive and pest species that threaten other species.
John Avise, Research Professor, Department of Genetics, University of Georgia
THE HISTORY AND PURVIEW OF CONSERVATION GENETICS
An examination of the recent scientific literature described by various authors as "conservation genetics" provides a basis for the current attempt to orient this applied subdiscipline of conservation biology conceptually. At least six overlapping subject areas are recognizable: (A) within-population assessments (e.g., of inbreeding, heterozygosity, genetic fitness, population viability); (B) geographic variation (metapopulation structure, gene flow, phylogeography, stock identification); (C) species-level issues (taxonomic boundaries, hybridization, introgression, phylogenetics, conservation "worth," identification of biodiversity hotspots); (D) forensic identification of wildlife products (e.g., in law enforcement); (E) monitoring the genetic effects of released toxins and other environmental insults; and (F) direct manipulation of genes and organismal reproduction in conservation efforts. The scope of conservation genetics is outlined by examining the historical roots of these varied topics and their relative emphases. Genetic theory and principles, as well as empirical evaluations of both molecular and non-molecular genetic traits, have all played key roles in the emergence of conservation genetics as a recognizable area within conservation biology.
Judith A. Blake, Research Scientist, Mouse Genome Informatics, The Jackson Laboratory
COMPARATIVE GENOMICS AND THE CONSERVATION OF BIODIVERSITY
The availability of complete genomes has transformed our approach to comparative genome analysis and has provided insights and new approaches to the study of the common set of genes and proteins shared among all organisms. With the extensive availability of molecular sequence data, experimental biologists now combine sequence similarity characteristics with analysis of mutant phenotypes to explore the function and regulation of genes and proteins and their impact on phenotypes. Knowledge about proteins in one organism can often be transferred to other organisms, and often provides the catalyst for further discovery. I will provide examples of several types of comparative genome analyses and discuss the impact on the discovery, analysis, and conservation of biodiversity. I will also discuss the development of the Gene Ontology, a project to provide a dynamic, structured, shared vocabulary that can be applied to all organisms.
Joel Cracraft, Curator, Ornithology, Division of Vertebrate Zoology, American Museum of Natural History
SPECIES AS TAXA: THE UNITS OF BIOLOGICAL DIVERSITY AND CONSERVATION
Species are commonly units of conservation action, but there is considerable difference of opinion over what is a species. Different species concepts result in fundamentally different approaches to understanding pattern and process in nature.
The species debate within conservation biology comes down to differences of opinion by those, mostly systematists, who advocate a species concept something near a phylogenetic species concept (PSC), and those, mostly population biologists and geneticists, who adhere to the biological species concept (BSC) but rarely use it to discriminate what we might call evolutionary (taxonomic) diversity.
The debate over units is clarified by realizing that (1) species are taxa, and as such, (2) are underpinned by a formal historical nomenclatural foundation, which other species-like "units" (such as "evolutionary significant units") do not have, and therefore (3) conservation biology will be better served by allying itself with formal systematics rather than adopting terminology not grounded at all in taxonomy. Genetic data are extremely important in conservation biology for many reasons. Nevertheless, to a systematist trying to individuate species taxa in nature, genetic data are just another form of evidence. Because the BSC places so much emphasis on genetic phenomena such as hybridization and reproductive isolation, use of that concept has confounded reconstructing history, which ironically leads to misinterpretations of the genetic data. Species concepts do constrain the way we see the world.
Philip Damiani, Research Scientist, Advanced Cell Technology
RECENT ADVANCES IN CLONING AND ITS APPLICATION IN CONSERVATION BIOLOGY
Extinction threatens multiple species. Given current trends, many rare or endangered vertebrate species will soon be lost despite efforts to maintain biodiversity through habitat and wildlife conversation. Even when a species is not endangered or threatened, the loss of biological diversity may lead to extinction of subspecies and other valuable genetic populations. One current method of preserving the genetic diversity of endangered species in captivity is through a series of captive propagation programs. These programs are not without limitations, however, which include limited physical space for animals, reproductive failure of the animals and general problems with animal husbandry. Recent advances in assisted reproductive techniques such as cryogenics of gametes/embryos, artificial insemination and embryo transfer have allowed for the further propagation of endangered species in both wild and captive populations. Most recently, with the progress in somatic cell nuclear transfer (cloning), there is growing scientific and public interest in using nuclear-transfer techniques to facilitate the rescue of endangered species. However, unlike the cloning of rodents and domestic animals, where there is a ready supply of oocytes and surrogate animals, the cloning of endangered species will require the use of an alternative method of cloning known as interspecies nuclear transfer. This technology can increase genetic diversity of a given species if used as part of a captive-breeding program.
James Gibbs, Assistant Professor, Department of Environmental Science and Forest Biolog, State University of New York College of Environmental Science and Forestry, Syracuse
RANGE COLLAPSES AND THE LOSS OF GENETIC VARIATION WITHIN SPECIES
Extirpation of local populations because of species range collapses is one of the least appreciated aspects of the current biological diversity crisis. Range collapse can, in particular, lead to the erosion of the component of genetic diversity within species that is unique to local populations. The dimensions of the issue are, however, poorly understood at present. Collector's curves applied to published gene frequency data can provide an intuitive means of examining the relationship between declining numbers of local populations and genetic diversity within a species, as well as for communicating what's at stake to policymakers.
Paul Z. Goldstein, Assistant Curator, Division of Insects, Field Museum
RECENT CHARACTER FIXATION IN THE NORTHEASTERN BEACH TIGER BEETLE: IMPLICATIONS FOR THE PHYLOGENETIC SPECIES CRITERION
Implications of the phylogenetic species criterion are explored using a reductio ad absurdum involving the recent fixation of a single base pair in a population of the federally threatened Northeastern Beach Tiger Beetle Cicindela dorsalis dorsalis (Coleoptera: Carabidae), formerly distributed more or less continuously along the Atlantic coastline. Earlier studies have demonstrated the diagnosibility of New England's remaining populations via a single base pair in the mitochondrial COIII gene. In this study, "ancient" DNA was extracted from museum specimens collected from throughout the species' former range. It shows that the diagnosibility of the extant Massachusetts populations is the result of character fixation, due in part to the extirpation of populations between New England and the Chesapeake Bay, i.e. the recent extinction of polymorphism at the site in question. The notion of speciation as the evolution of reproductive isolation is compared to the idea of species delimitation—with the aim of recovering phylogenetic history—through the identification of diagnosable groups of organisms.
Eric M. Hallerman, Associate Professor, Department of Fisheries and Wildlife Sciences, Virginia Polytechnic Institute
ECOLOGICAL AND EVOLUTIONARY ISSUES POSED BY GENETICALLY MODIFIED FISHES
With the prospect of improved production efficiency, it is not surprising that some aquaculturists want to produce transgenic fish and shellfish commercially. Gene transfer can be applied to achieve dramatic impacts upon performance, increasing the growth rate of fish four- to six-fold. Commercialization of transgenic fish and shellfish is controversial, however, in part due to concerns about possible ecological and evolutionary impacts. Ecological hazards include the possibility of heightened predation or competition, colonization of ecosystems outside the native range of the species, and alteration of population or community dynamics by the genetically modified organism (GMO). Fertile GMOs could interbreed with natural populations; any genetic or evolutionary impacts would depend on the fitness of novel genotypes in the wild. Empirical data regarding ecological and evolutionary risk are quite limited. While cases posing serious hazard may prove the exception, the potential for hazard argues for careful risk assessment and risk management. Application of biotechnology may play a role in reducing risk, for example, through production of all-female triploid aquaculture stocks.
Phil Hedrick, Ullman Professor, Department of Biology, Arizona State University
NEUTRAL, DETRIMENTAL, AND ADAPTIVE GENETIC VARIATION IN CONSERVATION GENETICS
Genetics studies in endangered species have become widespread in the last decade, and with new information from various genome projects, new applications and insights are forthcoming. Generally, neutral variants are used for conservation applications, and with highly variable loci and/or many more markers, these approaches should become much more informative. However, conservation genetics is also concerned with detrimental and adaptive variation. Examples from Mexican wolves and Arabian oryx will be presented. Identification and characterization of this variation is more difficult, but the ability to predict the extent of detrimental and adaptive variation may become more successful and applied in future conservation.
Kent Holsinger, Professor, Ecology & Evolutionary Biology, University of Connecticut
GENETICS AND EXTINCTION IN FRAGMENTED POPULATIONS
The small populations that remain in habitat fragments may tend to lose their genetic diversity because of their small size. But many populations are naturally patchy and small. Fragmentation will affect the genetic structure of such populations far less than it will affect that of populations that are widespread and continuously distributed.
Fragmentation enhances loss of diversity when it inhibits the exchange of genes among populations. But it may increase the exchange of genes if the matrix separating populations from one another is not a significant barrier to dispersal. Studies of a dioecious orchid in central Panamá show that small populations found on islands isolated by construction of the Panamá Canal have a genetic structure similar to populations remaining in intact forest. Estimated rates of gene dispersal suggest that these populations remain well-connected.
Molecular markers, like allozyme or microsatellite loci, provide interesting data on gene dispersal among populations, but it is often difficult to discern how to apply these data to conservation problems. The pattern of population differentiation for traits is greatly affected by the type of selection to which those traits are subject. Populations may either be substantially more differentiated or substantially less differentiated than molecular marker data would suggest.
Robert C. Lacy, Population Geneticist, Department of Conservation Biology, Chicago Zoological Society
STOPPING EVOLUTION: GENETIC MANAGEMENT OF CAPTIVE POPULATIONS
Stopping evolution: Genetic management of captive populations. Captive populations can serve as sources for reintroduction of extirpated wild populations, sources for reinforcing genetically or demographically fragile populations, appropriate models for research, and foci of conservation education programs. Yet all these values depend on a captive population maintaining a genetic composition comparable to the wild population it represents. This requires breeding programs that minimize damage from inbreeding, slow random genetic drift, and minimize adaptation to captive conditions (domestication). Thus, we wish to stop evolution of the captive population into an organism quite different from the wild progenitors. Genetic management strategies for captive populations have evolved rapidly over the last 20 years from simply avoiding inbreeding, to equalizing family sizes, to equalizing founder contributions, to minimizing mean kinship. Through computer simulations, the effectiveness of strategies for preventing evolutionary change in captive breeding programs was evaluated. Pedigree management techniques are identified that minimize the random genetic change, reduce the rate of domestication, and are robust to small numbers of errors in our knowledge of the pedigree structure. Still, rates of genetic change in captive populations of the size often maintained in zoos may be too high to provide assurance that long-term captive populations will retain their genetic diversity and integrity.
Craig Moritz, Director, Museum of Vertebrate Zoology, and Professor of Integrative Biology, University of California Berkeley
UNITS IN CONSERVATION GENETICS: WHAT IS USEFUL?
There is continuing debate among geneticists and systematists over how best to represent biological diversity at or around the species level for the purpose of conservation assessment. One source of disagreement relates to long-standing debates over concepts and criteria for recognizing species. Another is how best to identify and manage genetic diversity within taxa. Throughout there is confusion over goals and, often, superficial application of criteria, rather than careful consideration of goals and appropriate strategies based on our knowledge of process for the system in question. In the context of a goal to preserve evolutionary processes, I suggest that we should separate genetic diversity arising from adaptive vs. vicariant processes and develop different strategies to deal with each of these. Whatever approach we adopt to recognise species or intraspecific units, we should recognize the dangers inherent in the sometimes necessary imposing of thresholds or boundaries on a genealogical continuum of evolutionary divergence.
Steve R. Palumbi, Professor of Biology and Curator of Invertebrates, Museum of Comparative Zoology, Harvard University
THE VALUE OF GENETICS IN CONSERVATION BIOLOGY: PAST SUCCESS AND FUTURE TRAJECTORIES
Molecular genetics is most powerful in population and conservation biology when it provides information not available using other approaches, or when it complements information from other sources. So far, genetics has informed conservation efforts in several key ways. Population structure and reductions of genetic diversity in small populations have been a common focus of genetic studies, but these do not necessarily provide the most influential conclusions. This is partly because population genetics frequently focuses on gene flow over evolutionary time scales, which are too long for most managers to accommodate, and because there is no simple relationship between genetic diversity and population fitness in the wild. Other aspects of conservation genetics for future efforts include: 1) delineation of cryptic species, 2) identifying exploitation of protected populations and species using forensic approaches, 3) genetic databasing and identification of individuals and genealogies in wild populations, 4) elucidation of historical population sizes and recent demographic histories of threatened populations, 5) understanding the nature of local adaptation and species boundaries, and 6) using high resolution genetic structure to measure dispersal over ecological time frames. These are achievable given current genetic technology, and should be more and more feasible as the ability to collect large population-level genetic data sets increases.
Barbara A. Ruskin, Molecular Biologist, Patent Attorney and Associate, Fish & Neave, and
Gerald J. Flattmann, Jr., Patent Attorney and Partner, Fish & Neave
CAN OUR LAWS ACCOMMODATE THE NEW CONSERVATION GENETICS?
The new genetic technologies available to conservation biologists pose complex and profound questions scarcely contemplated when the existing legal framework was enacted. We examine relevant laws and consider whether they can adequately accommodate the broad range of legal and moral issues raised by those technologies. In particular, we consider the likely impact on new genetic technologies of existing laws concerning intellectual property and the preservation of biodiversity. Specifically, we assess the patentability of whole organism somatic clones of endangered and previously extinct species, and consider whether creating ownership interests in cloned species is consistent with the aims of landmark conservation legislation. We further consider whether somatic cloning of whole organisms would ultimately advance or subvert the aims of the Endangered Species Act and similar international laws and whether the introduction of cloned species into the wild or the marketplace would be impacted by a host of other laws and regulations, such as environmental protection laws, the Food, Drug & Cosmetics Act, and the National Forest Management Act. Finally, we consider whether meaningful legal protection exists (or should exist) under the Copyright Act and trade secrecy law for the new "libraries" of conservation biology, such as frozen tissue collections and bioinformatics databases.
Oliver A. Ryder, Kleberg Chair in Genetics, Center for Reproduction of Endangered Species, Zoological Society of San Diego
CONSERVATION AND GENOME RESOURCE BANKING
The future of conservation genetics will depend upon what we can save of what is extant. The value of genetic resource collections cannot be overlooked. Although we may not be able to anticipate the future uses of collections of viable frozen cells and extracts of nucleic acids, access to these materials is more readily available now than will be the case in the future. What would the future ask us to be doing now?
Knowledge of the molecular basis of evolutionary adaptations will be the subject of fundamental scientific curiosity and entrepreneurial interest. Extreme dietary specializations, adaptation to a fully aquatic existence, and other changes have occurred in a convergent fashion among the major superordinal clades of eutherian mammals. Comparative genomics studies will offer new insights and provide a framework for interpreting adaptive changes in animal genomes.
The potential for genomics information to assist in the assessment, monitoring and management of populations of endangered species should be recognized and expanded. Applications include animal health - through diagnostics and species-specific pharmacology, evaluation of population viability and elucidation of the molecular basis of adaptations.
Similarly, the availability of the human genome sequence and information regarding its variation will soon focus attention on the humanitarian value of genomic information that can only be provided by studies of closely related species, such as the great apes, and of more distantly related species. This awareness comes at a time when increased conservation measures are urgently needed for all species of great apes and other endangered species as they face the risk of extinction in their native habitats. The value to humankind of comparative genomics data, especially from species of primates, should be recognized by society and within the wider biomedical industry and the appropriate ethical and legal approaches be promulgated.
Barbara A. Schaal, Professor, Evolutionary and Population Biology, Washington University
BIODIVERSITY, GENETIC DIVERSITY, AND CONSERVATION
Plant conservation biologists are concerned with biodiversity at three levels: community diversity, species diversity and genetic diversity. Both theoretical and experimental studies have demonstrated the importance of maintaining high levels of genetic diversity within species for long-term survival. Loss of genetic diversity can result in loss of plant fitness due to increased homozygosity and fixation of alleles with deleterious effects. Likewise, loss of genetic variation can reduce the evolutionary potential of a species to adapt to different environments. Mead's milkweed is a threatened prairie plant of the midwest United States. Both population numbers and sizes have been severely reduced due to agriculture. An analysis of genetic variation within and among populations of Mead's milkweed by Random Amplified Polymorphic DNA measured the number of individuals and their clonal structure. Some populations of Mead's milkweed contain few genotypes. No seeds are produced in several of these populations due to self-incompatibility. To assure the long-term survival of Mead's milkweed, conservation and restoration efforts require the infusion of multiple genotypes to restore seed production.
Barbara L. Taylor, Conservation Biologist, National Marine Fisheries Service Southwest Fisheries Science Center
MAINTAINING POPULATIONS AS FUNCTIONING ELEMENTS OF THEIR ECOSYSTEM: THE ROLE OF MANAGEMENT UNITS
Conservation is not limited to managing endangered species. Maintaining healthy functioning ecosystems often requires active management of many abundant and often continuously distributed species. Because human impact is always uneven across a species' range, successful management requires understanding population structure. Understanding structure can allow management to prevent localized over-exploitation that would result in range fragmentation or contraction. Genetic data can be used as a tool to estimate dispersal and the locations of restrictions in gene flow. Unfortunately, standard hypothesis testing approaches often conclude that there is no evidence for population structure. Data from the scientific whaling of North Pacific minke whales provides an example of the hazards of interpreting genetic data. The development of estimation techniques is demonstrated and reveals how small dispersal rates that are demographically trivial with respect to managing harvest can be difficult to detect using standard hypothesis testing. A technique to estimate the power to detect structure is again shown using the minke whale example.