Long-Term Stability in Genomic Clines in Natural Populations of Drosophila melanogaster

Abstract

The sequencing of historical samples has proved to be a powerful ally in the study of evolutionary processes of natural populations and can be used to investigate possible evolutionary changes related to global warming. At the same time, the study of clines can help to link genotypic and phenotypic variants to environmental variables. This work will assess how the clinal patterns of natural populations in the North American latitudinal gradient of D. melanogaster have changed over the last few decades. For this, it will use pool-seq and sequencing of isochromosomal lineages collected at three different time points (1997, 2009/2010 and 2017). Two main patterns of clinal changes can emerge: clines may become less steep, with populations becoming more similar; or the entire cline may shift, with the most common variants in the south increasing in frequency along the entire latitudinal gradient. The first case is expected if clines were initially generated by demographic history. On the other hand, if climate change is the main force driving changes in these decades, it is expected that coding regions, especially genes linked to high-temperature tolerance, will be the most affected. We hope with this study to understand how the genomic pattern of clines has changed in recent decades and whether this change can be related to climate change.