Beyond single-nucleotide polymorphisms: how are large-scale genome sequencing approaches revolutionizing our understanding of inter-individual

Genome-wide association studies identify links between DNA variations and traits in humans (and other species) of commercial, societal or ecological importance. Traditionally centered on model organisms, DNA sequencing approaches have recently extended to non-model species, revealing unexpectedly complex genomic architectures in organisms previously regarded as simple or primitive. While genetic variation has long been viewed as linked to small-scale point mutations, these new approaches reveal the widespread occurrence of large structural chromosome rearrangements that can alter gene repertoires across individuals. This shift has introduced the concept of the pangenome, which includes all genes: the “core” genes shared by all individuals and the “dispensable” ones only found in some populations. These dispensable genes often aid species adaptation and survival in challenging environments. The biological relevance of these accessory genes is yet to be fully understood, but they are most likely linked to the ability to adapt to challenging conditions and colonization of new environmental niches.