Safeguarding genetic diversity - the raw material for species' survival.
At a time when major changes are affecting the environment - climate change, habitat change, landscape change - the planet's biodiversity is increasingly under potential threat.
© Uryadnikov Sergey fotolia
Yet, while much attention has been paid to preserving biodiversity at species level and entire ecosystem level, very little focus has been applied to a crucial third level: genetic biodiversity.
“Genetic biodiversity is that part of biodiversity that can be found within a species as opposed to between species,” says Professor Mike Bruford of Cardiff University’s School of Biosciences in the United Kingdom. “As well as looking at the number and variety of ecosystems and of species, genetic diversity is equally important. But this third layer has always been neglected in policy terms until now,” he adds.
Professor Bruford is Project Coordinator of CONGRESS, a European Union (EU)-funded research project, which worked towards filling this ‘policy vacuum’ by harnessing the latest technology and making it easier to incorporate genetic diversity aspects into future conservation policy and management.
“As Darwin and Wallace told us, without genetic diversity, species cannot evolve,” says Professor Bruford. “With the present changes in climate and other alterations in habitat and landscape, species need that fund of diversity to survive.”
The focus of the CONGRESS team was to create a web portal containing three vital new tools for the understanding and management of genetic biodiversity: a set of genetic databases, a simulation tool to help biodiversity managers predict outcomes based on known genetic data, and a decision matrix module to identify the best management options. The web portal, and in particular the simulation tool, is also used for educational purposes.
Underlining the significance of this effort, CONGRESS researchers estimate that 80% of endangered species today suffer from low levels of genetic diversity. One major cause of the ‘genetic erosion’ that is taking place is human agriculture. With its increasing reliance on highly selective breeding, human agriculture not only reduces the overall number of breeds in existence, but it also has important effects within any given breed. “Look at Europe’s many millions of Holstein Friesian cows,” he says. “Nearly all of them are sired by 100 bulls. And the top 20 of those bulls account for 50% of that. So we are narrowing the gene pool in favour of individual genomes that have been highly selected for the traits we are interested in. We are producing these highly elite, artificially selected lines, but they do not have very much genetic diversity, so if anything changes they are not in a position to respond,” explains Professor Bruford.
Genetic erosion occurs in wild species as well. One cause is habitat fragmentation. If part of a forest is cut down, for example, the population of a species living in that forest can become fragmented as well. The separated groups are unable to interact, and genetic diversity is thus eroded. Another common reason is the impact of invasive species, often as a result of climate change.
In terms of their practical application in such situations, genetic techniques have much to offer, according to Professor Bruford. “If you have a small population which is going extinct and you want to trans-locate some individuals into it,” he explains, “then you need to make sure they are genetically compatible. Or let’s say you have two forest populations separated by a couple of kilometres and you build a corridor between them. If those two populations are distinct from each other you can measure the genes in the two populations and tell whether or not they have actually migrated across.”
The key to developing a stronger focus on genetic biodiversity is the fact that recent advances in technology have led to a significant fall in costs. For example, the cost of sequencing DNA is rapidly declining. It is no longer prohibitively expensive to use these tools. “However,” notes Professor Bruford, “genetic approaches are still not widely implemented.” “There are two possible reasons why this might be the case,” he concludes. “Either policymakers do not understand it, or we as scientists are not properly communicating it. Those two issues are exactly what CONGRESS was designed to solve.”