10.5061/DRYAD.3P4H2
Zee, Peter C.
Indiana University Bloomington
Velicer, Gregory J.
Indiana University Bloomington
Data from: Parallel emergence of negative epistasis across experimental
lineages
Dryad
dataset
2017
Parallel evolution
Myxococcus xanthus
Epistasis
genetic co-option
2017-01-18T15:33:29Z
2017-01-18T15:33:29Z
en
https://doi.org/10.1111/evo.13190
146924 bytes
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CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
Epistatic interactions can greatly impact evolutionary phenomena,
particularly the process of adaptation. Here, we leverage four parallel
experimentally evolved lineages to study the emergence and trajectories of
epistatic interactions in the social bacterium Myxococcus xanthus. A
social gene (pilA) necessary for effective group swarming on soft agar had
been deleted from the common ancestor of these lineages. During selection
for competitiveness at the leading edge of growing colonies, two lineages
evolved qualitatively novel mechanisms for greatly increased swarming on
soft agar, whereas the other two lineages evolved relatively small
increases in swarming. By reintroducing pilA into different genetic
backgrounds along the four lineages, we tested whether parallel lineages
showed similar patterns of epistasis. In particular, we tested whether a
pattern of negative epistasis between accumulating mutations and pilA
previously found in the fastest lineage would be found only in the two
evolved lineages with the fastest and most striking swarming phenotypes,
or rather was due to common epistatic structure across all lineages
arising from the generic fixation of adaptive mutations. Our analysis
reveals the emergence of negative epistasis across all four independent
lineages. Further, we present results showing that the observed negative
epistasis is not due exclusively to evolving populations approaching a
maximum phenotypic value that inherently limits positive effects of pilA
reintroduction, but rather involves direct antagonistic interactions
between accumulating mutations and the reintroduced social gene.
E1_DATAE1 swarming dataE2_DATAE2 swarming dataE7_DATAE7 swarming
dataTOTAL-E8-PILAE8 swarming dataGVTu1_contPlasmid control
dataGJV6-pilA_controlSwarming controls