Selection shapes the evolution of genome size in a globally invasive plant.

Abstract

Biological invasions provide powerful natural experiments for understanding how genome architecture responds to novel climatic environments. Transposable elements (TEs) can rapidly restructure genomes, yet their role in adaptive genome size evolution during invasion remains poorly understood. Here, we examined genome size and TE abundance in 439 individuals of globally invasive common ragweed (Ambrosia artemisiifolia L.) across native (North American) and invasive (European, Australian) ranges. By integrating whole-genome resequencing, flow cytometry and trait vs genetic differentiation comparison (QST-FST), we tested whether genome size evolution is shaped by selection, climate and life-his..