Background of the project
What is "assisted gene flow"?
Imagine for a moment to play one of those plumbing games where you have to connect different pipes to let the water flow from point A to point B: The individual pipes are the populations and the water flowing in the pipes represents the "genetic diversity".
Now, the "main" metapopulation (population B) is well connected to other sub-populations, is large in size (n) and can rely on a good level of resilience granted by highly variable alleles shared by every subpopulation. Population A, on the other hand, is isolated from the other populations by a barrier (for example a vast area unsuitable for colonization), has a low number of individuals (n) and hence possesses a less variable allele set. There is not enough "flowing water" for ensuring resilience for responding against - for instance - the spread of a pathogen. This situation can lead to a wide array of scenarios, many of which are likely to end up with local extinction for population A. In the cases where this situation is the result of human activities, it is desirable to intervene with suitable measures, whose typically aim at restoring "connection" between subpopulation through ecological corridors or patches, when this is feasible.
Last-resort measures are then put into place when other solutions are not suitable anymore. Assisted gene flow (AGF) fits in this last category of measures and consists of the intentional human-managed movement of individuals between populations to facilitate gene flow and thus, reduce inbreeding levels. As mentioned above, this is a last-resort measure and it is considered only when the species under special attention is endangered and experience a realistic risk of extinction in the short- or medium-term since there are risks connected with such measures (e.g. outbreeding depression, disruption of gene complexes).
Why studying local adaptation is so important?
Local adaptation occurs when a population evolves (through natural selection) traits that confer higher fitness in the environment where evolved such traits compared to any other environment. This means that locally adapted populations developed during evolution an "affinity" to their local environmental conditions. Along a determinate environmental gradient (e.g. altitude) different populations of the same species are thus well suited for that specific combination of temperature, pressure, UVB radiation levels, etc. In this context, when it comes to reintroduction or assisted colonization/migration measures, it is fundamental to consider this phenomenon for the success of such actions.
KEY CONCEPTS:
Gene flow, assisted gene flow, metapopulation, population, genetic diversity, allele, inbreeding, outbreeding depression, local adaptation, natural selection, environmental gradient.
Aims of the project
•Detect signatures of local adaptation by assessing geographic patterns of secondary metabolites variation
•Detect genetic markers linked to chemotype and environmental variation
•Detect evolutionarily significant units (ESU)
•Employ such knowledge for the identification of patterns of adaptive genetic variation
Main hypothesis
Secondary metabolites relative composition is expected to vary along the gradient considered since herbivory levels are expected to change along the gradient too.
In this context, local adaptation could play a fundamental role in regulating herbivore-plant interactions.