Conservation genomics is a recent introduction in the conservation biologist’s tool kit that is helping in better understanding of conservation needs and providing newer avenues to expand conservation efforts. Conservation genomics has been defined and explained by many research groups in different ways, but simply it may be summed up as the application of modern genomic techniques and genomic data to solve problems in conservation biology. It integrates conservation genetics with ecological and evolutionary genomics.
Genomic diversity is the base of all diversity among living beings, and may be referred as the first level of biodiversity, followed by diversity at species, community and ecosystem levels. There is considerable diversity in genomes within the same species; while some of the genomic regions show no variation, i.e. may be conserved, other parts of the genome show hypervariability. Understanding such genomic variations and deciphering the parts required for organismal survival is essential in conservation studies.
As the global environment continues to undergo rapid changes, conservation biologists are facing newer and difficult challenges. They now have to be prepared to be able:
- To predict the effect of changing climate on biological diversity
- To prioritise conservation goals
- To conserve such biodiversity which would help in maximising species adaptation to newer habitats
- To predict adaptation rate and direction
- To elucidate the response of biodiversity to these changes
Genomics approaches can help in understanding the functionally important genomic variations and mechanisms underlying phenomena such as inbreeding depression, and other useful parameters while designing conservation strategies.
Genomic tools are opening up unexplored niches for conservation biologists in different ways. Extensive genomic sequence information in non-model organisms is becoming readily available, which is proving instrumental in developing large number of markers distributed across the genomes, thus allowing one to explore genome wide genetic variations. These markers are useful in studying variations within individuals, populations and metapopulations. These studies can be used to obtain changing trends in demography, gene flow, inbreeding and population history. These markers play a key role in population genomics, to study gene selection during evolution by studying the pattern of inheritance of a maker linked to a locus over the time span under study. As the number of available markers increases, it will become easier to simultaneously genotype numerous individuals, thereby leading to increased accuracy in estimation of parameters like migration rate, migration direction i.e. immigration or emigration, population bottlenecks, and growth rates. Increased marker numbers will also aid in kinship estimates in pedigree analysis of a species. Genome scans using large number of markers are being utilized to detect signatures of inbreeding depression by identifying deleterious recessive alleles.
Genomics is being utilized to estimate species introgression rates due to hybridization. This increased accuracy is helping in accurately estimating the levels of admixtures in genetically divergent populations. On parallel lines, genomic approaches can be applied to detect outbreeding depression as it will be possible to estimate genetic makeup of progeny produced by a population of individuals having varying degrees of admixtures.
Analysis of variations at the gene expression level are helpful in understanding changes in gene expression due to genetic drift, inbreeding or any other physical factor such as habitat change. This stems from the hypothesis that gene expression patterns are more influenced by phenotypic variations than the gene sequences. Studies are being designed to understand genomic mechanisms of environment adaptation, identify genes having adaptive importance and pathways of phenotypic plasticity. To this effect, population transcriptomics is being employed to study gene expression as a function of habitat fragmentation and environmental change. In parallel, the effects of population fragmentation and genetic drift are also being studied by newer approaches like population proteomics and population metabolomics. Role of transcription regulatory mechanisms in governing the environment associated gene expression is being studied using epigenomics.
All these techniques together are building up a framework of conservation studies that will help in better understanding of the interactions among environmental change and genetic erosion. Thus conservation genomics encompasses a multidisciplinary approach to assess the impact of genetic and environmental threats to species. Application of genomic techniques in conservation strategies has the potential to revolutionize the methods of population management, as it can provide advanced methodologies that can assist in a number of ways ranging from pedigree estimation using large number of markers to identification of genomic loci responsible for adaptation. The most important contribution of genomics will be the ability to precisely monitor changes in allelic frequency to estimate genetic drift, natural selection and hybridization in wild and captive populations.