Abstract:
The importance of whole-genome
duplication (WGD) for evolution is controversial.
Whereas some view WGD mainly as detrimental and an evolutionary dead end, there
is growing evidence that polyploidization can help overcome environmental change,
stressful conditions, or periods of extinction. However, despite much research, the mechanistic
underpinnings of why and how polyploids might be able to outcompete or
outlive nonpolyploids at times of environmental upheaval remain elusive, especially for
autopolyploids, in which heterosis effects are limited. On the longer term, WGD might
increase both mutational and environmental robustness due to redundancy and increased
genetic variation, but on the short—or even immediate—term, selective advantages of
WGDs are harder to explain. Here, by duplicating artificially generated Gene Regulatory
Networks (GRNs), we show that duplicated GRNs—and thus duplicated genomes—
show higher signal output variation than nonduplicated GRNs. This increased variation
leads to niche expansion and can provide polyploid populations with substantial
advantages to survive environmental turmoil. In contrast, under stable environments,
GRNs might be maladaptive to changes, a phenomenon that is exacerbated in duplicated
GRNs. We believe that these results provide insights into how genome duplication and
(auto)polyploidy might help organisms to adapt quickly to novel conditions and to
survive ecological uproar or even cataclysmic events.
