Gene mixing, not chromosome doubling, drives crop evolution in hybrid plants
A new study challenges decades of assumptions about how polyploid crops develop, showing that hybridization—not whole-genome duplication—controls gene behavior in new plant varieties. The finding could reshape breeding strategies for creating more resilient crops as agriculture faces climate pressures.
Originaltitel: Expression pattern of resynthesized allotetraploid <em>Capsella</em> is determined by hybridization, not whole genome duplication
<ul><li>Polyploidization, the process leading to the increase in chromosome sets, is a major evolutionary transition in plants. Whole-genome duplication (WGD) within the same species gives rise to autopolyploids, whereas allopolyploids result from a compound process with two distinct components: WGD and interspecific hybridization.</li><li>To dissect the instant effects of WGD and hybridization on gene expression and phenotype, we created a series of synthetic hybrid and polyploid <em>Capsella</em> plants, including diploid hybrids, autotetraploids of both parental species, and two kinds of resynthesized allotetraploids with different orders of WGD and hybridization.</li><li>Hybridization played a major role in shaping the relative expression pattern of the neo-allopolyploids, whereas WGD had almost no immediate effect on relative gene expression pattern but, nonetheless, still affected phenotypes. No transposable element-mediated genomic shock scenario was observed in either neo-hybrids or neo-polyploids. Finally, WGD and hybridization interacted and the distorting effects of WGD were less strong in hybrids. Whole-genome duplication may even improve hybrid fertility.</li><li>In summary, while the initial relative gene expression pattern in neo-allotetraploids was almost entirely determined by hybridization, WGD only had trivial effects on relative expression patterns, both processes interacted and had a strong impact on physical attributes and meiotic behaviors.</li></ul>