Cornerstone Of Conservation Genetics In Biodiversity Conservation
Conservation genetics is a mixture of ecology, population genetics, molecular biology, mathematical modelling and evolutionary systematic. It is an interdisciplinary science that aims at applying genetic methods to the conservation and restoration of biodiversity (Woodruff 2001).
The organisms under research are usually endangered or threatened populations. To develop a management strategy, lots of scientists have asked: what has brought these populations to the brink of extinction, and what steps can be taken to reverse this trend? (Woodruff 2001, Morin et al. 2004). Information about the genetic diversity of the animals, including terrestrial and marine organisms, under study helps scientists and mangers in forming strategies to preserve and protect the diversity of organisms worldwide.
One of techniques, molecular technique, can be used to address questions of biodiversity conservation. The application of molecular techniques to conservation field has recently been well explored (Frankham et al. 2002). These questions concern how kinship affects reproduction, group structure, dispersal, and cooperation which leads to social group assembly rules such that population can be genetically managed and restored. Therefore, here this essay will talk about why conservation genetics is a cornerstone of biodiversity conservation by comparing conservation biology from the past to the present and future
In the past decades, the field of conservation genetics was focused on two questions. The first concerned is the level of genetic variation in populations, and the risk of low levels of variation and future genetic losses caused their continued existence. A typical study was estimate variation across the range of a species for several loci which thought to be largely affected by selection and it indicated variation in the genomic background. Population with low levels of variation were at risk of the problem of inbreeding depression, and of future variation losses are significant for an effective adaptive response to changing conditions (Wayne and Morin 2004).
A second question focused on the historical isolation and the level of gene flow between populations. Genetic analysis provided an assessment of the potential for populations to exchange migrants, and identified genetically divergent populations (Wayne and Morin 2004).
The majority of conservation genetics studies have relied on mitochondrial DNA, chloroplast DNA, and unclear microsatellite loci, all of which are generally assumed to be selectively neutral and highly variable genetic markers, suitable for population- level analyses (Wayne and Morin 2004).
The present concerned questions of conservation genetics have develop to some extent, and give us some answers as well.
Question In Relatedness, Inbreeding, And Fitness
Levels of genomic variation and population distinction are critical issues. The focus of this study has obscured other genetic issues of great importance to population management and to the evolutionary processes that will enable populations to survive. Recent genetic studies using microsatellite markers have shown how kinship affects reproduction, group structure, cooperation, and dispersal (Ross 2001).
Inbreeding leads to reduction of genetic variation and increased genes which have a deleterious effect on fitness will be expressed. Both of them can result in a reduction in fitness and could cause a population decline (Wayne and Morin 2004). In the wild, inbreeding depression has been shown to affect birth weight, survivorship, reproduction, resistance to disease, and responses to environmental stress (Keller and Waller 2002; Schiegg et al. 2002). To detect inbreeding depression, scientists estimated fitness by comparing the genealogical relatedness of individuals (Amos and Balmford 2001).
Question In Population Assignment, Gene Flow, And Migration
Recently, analytical techniques have been developed to assign individuals to specific populations based on microsatellite markers, and asses the contribution to the genome of each individual from different source populations (Pritchard et al. 2000; Blanchong et al. 2002; Manel et al. 2002).
One important distinction for conservation is the difference between gene flow and migration. The gene flow involves the exchange of individuals between populations who succeed in reproducing. However, migration might only involve the recent movement of individuals between populations. In addition, population assignment data can be used to estimate migration rates (Blanchong et al. 2002; Manel et al. 2002). The estimation of migration rates is important information for metapopulation models which used to predict future demographic changes, and determining the origins of colonists to identify the sources of recruits to rescue declining populations (Stow et al. 2001).
Question In Non-Invasive Monitoring
Monitoring the demography of species that are difficult to observe and capture utilizes material. In recent, new molecular techniques allow the extraction of DNA from organisms remains such as feathers , hair, an d bone, revealing a non-invasive genetic record of individuals (Morin and Woodruff 1996). Scientists take advantage of characterization of these remains using genetic markers offers a way to count and identify individuals in a population, determine their sex and movement patterns (Kohn and Wayne 1997). Non-invasive approaches are very promising methods for monitoring threatened population, as they avoid the disruption and possible harm caused by handling (Mills et al. 2000; Waits et al. 2001).
Question In Adaptation And Evolutionary History
The majority of conservation genetic evaluations are based on neutral markers which are influenced by genetic drift (Reed and Frankham 2001). Conservation genetic uses neutral markers to assess population history and demography, as well as assays of fitness-related traits to preserve adaptive diversity (Wayne and Morin 2004).
A primary goal of conservation biology is to enhance the long-term survival of species and the ecosystems on which they depend. The focus of molecular studies is more directly assaying traits relevant to individual survival and reproduction (Wayne and Morin 2004).
The power of these techniques will increase dramatically in the near future, as sequencing and genotyping become more widely used and genome sequencing projects of model species provide functional genes that can be surveyed. The techniques will enable a new series of questions to be addressed (Wayne and Morin 2004).
Conservation genetics focuses on the characterization of variation in populations and species and on the management of levels of variation in evolutionarily units in nature. Conservation genetic methods are from evolutionary biology and molecular genetics; however conservation genetic is under development. Although, conservation genetics is still in its infancy, it provides the technical underpinnings of conservation biology. Although some genetic management principles flow from current evolutionary theory, several key problems remain to be solved. Although single species ecological methods have dominated conservation management practice, it is clear that the future evolvability of species will require greater genetic intervention. So conservation genetics is a cornerstone of biodiversity conservation.
1. Amos, W. a Balmford, A. 2001. When does conservation genetics matter? Heredity 87: 257-65.
2. Blanchong, J. A. Scribner, K. T. Winterstein, S. R. 2002. Assignment of individuals to populations: Bayesian methods and multi-locus genotypes. J Wildlife Manage 66: 321-29.
3. Frankham, R. Ballou, J. D. Briscoe, D. A. 2002. Introduction to conservation genetics. Cambridge, UK: Cambridge University Press.
4. Keller, L. F. Waller, D. M. 2002. Inbreeding effects in wild populations. Trends Ecol Evol 17: 230-41.
5. Kohn, M. H. Wayne, R. K. 1997. Facts from feces revisited. Trends Ecol Evol 12: 223-27.
6. Manel, S. Berthier, P. Luikart, G. 2002. Detecting wildlife poaching: identifying the origin of individuals with Bayesian assignment tests and multilocus genotypes. Conserv Biol 16:650-59.
7. Mills, L. Citta, J. Lair, K. et al. 2000. Estimating animal abundance using non-invasive DNA sampling: promise and pitfalls. Ecol Appl 10: 283-94.
8. Morin, P. A. Woodruff, D. S. 1996. Non-invasive sampling for vertebrate conservation. In: Smith TB and Wayne RK (Eds). Molecular approaches in conservation. Oxford, UK: Oxford University Press. p 298-313.
9. Pritchard, J. K. Matthew, S. Donnelly, P. 2000. Inference of population structure using multilocus genotype data. Genetics 155:945-59.
10. Reed, D. H. Frankham, R. 2001. How closely correlated are molecular and quantitative measures of genetic variation? A metaanalysis. Evolution 55: 1095-03.
11. Ross, K. G. 2001. Molecular ecology of social behaviour: analyses of breeding systems and genetic structure. Mol Ecol 10: 265-84.
12. Schiegg, K. Pasinelli, G. Walters, J. R. Daniels, S. J. 2002. Inbreeding and experience affect response to climate change by endangered woodpeckers. P Roy Soc Lond B Bio 269: 1153-59.
13. Stow, A. J. Sunnucks, P. Briscoe, D. A. Gardner, M. G. 2001. The impact of habitat fragmentation on dispersal of Cunningham's skink (Egernia cunninghami): evidence from allelic and genotypic analyses of microsatellites. Mol Ecol 4: 867-78.
14. Waits, L. P. Luikart, G. Taberlet, P. 2001. Estimating the probability of identity among genotypes in natural populations: cautions and guidelines. Mol Ecol 10: 249-56.
15. Wayne, R. k.; Morin, P. A. 2004. Conservation genetics in the new molecular age. Front Ecol. Environment 2:89-97.
16. Woodruff, D. S. 2001. Population, species, and conservation genetics. Encyclopedia of Biodiversity 4:811-829.