The swallow (Hirundo rustica) DNA map is ready: it accurately and completely reconstructs the 80 chromosomes that make up the genetic heritage of the species, paving the way for the identification of the genes that control important characteristics such as migration and adaptation to changes climatic.
The result is published in Cell Reports by researchers from the University of Milan who, in collaboration with important foreign laboratories such as the Vertebrate Genome Laboratory of Rockefeller University (USA), have also created a catalog of all the genetic variants identified so far in the populations of swallows from all over the world.
Combining these resources, researchers have succeeded in constructing one of the first 'pangenomes' for a wild species, in practice a graphical representation which includes the complete sequence of the genomes of several individuals of the same species and which makes it possible to highlight similarities and differences that exist between them.
The concept of pangenome has recently been introduced in the field of human genetics (in particular by the American consortium of the Human Pangenome Project) in order to avoid the use of a single reference individual for population studies, which often leads to a reading partial or even distorted data.
Pangenomes are currently the primary focus of many groups worldwide studying the evolution and ecological adaptations of wild species,
The researchers' work also included comparing the swallow's genome with that of other bird species, for which a high-quality genome is available.
This has led to the identification of the regions of the genome which contain the genes which have, or have been, subjected to natural selection and which in many cases determine the peculiar characteristics of this species.
“Overall, the resources and results produced are intended to facilitate and support future studies on swallows, enabling the identification of genes that control important traits such as migration and adaptation to climate change, with results that may go well beyond the boundary of the studied species”, comments Luca Gianfranceschi, geneticist and coordinator of the new 'Biodiversity Genomics' research center at the State University of Milan.
