Reading DNA to reconstruct the demographic history of species

What if the evolutionary history of a species over the last millions of years could be reconstructed using genomic information from a few currently living individuals? This may sound like science fiction but has become a reality thanks to the recent revolution in sequencing techniques. As the DNA is transmitted across individuals from all their ancestors, it contains information about the demographic history of species, that is how the number of individuals has changed over time. A decline in the number of individuals in the past will result in a loss of genetic diversity that leaves footprints in the DNA. Complex statistical methods are used to read the DNA and convert genetic diversity patterns into complex demographic histories. I am interested in reconstructing the demographic history of the five endangered species of the Endemixit project to understand when and why the number of individuals started to decline.
For example, the demographic history of the Marsican brown bear has been reconstructed in a previous study using complete genomes of five individuals and revealed that around 3,000 years ago, the population underwent a severe reduction in population size. At that time, farming communities expanded in the area and intense forest burning took place. We can hypothesize that this intensification of human agricultural activity led to the decline of the Marsican brown bear population.
Therefore, reconstructing the demographic history from genomes of individuals can help to estimate the risk of extinction of species today and provide a valuable tool for the protection of biodiversity.

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