---
_id: '1125'
abstract:
- lang: eng
text: "Natural environments are never constant but subject to spatial and temporal
change on\r\nall scales, increasingly so due to human activity. Hence, it is crucial
to understand the\r\nimpact of environmental variation on evolutionary processes.
In this thesis, I present\r\nthree topics that share the common theme of environmental
variation, yet illustrate its\r\neffect from different perspectives.\r\nFirst,
I show how a temporally fluctuating environment gives rise to second-order\r\nselection
on a modifier for stress-induced mutagenesis. Without fluctuations, when\r\npopulations
are adapted to their environment, mutation rates are minimized. I argue\r\nthat
a stress-induced mutator mechanism may only be maintained if the population is\r\nrepeatedly
subjected to diverse environmental challenges, and I outline implications of\r\nthe
presented results to antibiotic treatment strategies.\r\nSecond, I discuss my
work on the evolution of dispersal. Besides reproducing\r\nknown results about
the effect of heterogeneous habitats on dispersal, it identifies\r\nspatial changes
in dispersal type frequencies as a source for selection for increased\r\npropensities
to disperse. This concept contains effects of relatedness that are known\r\nto
promote dispersal, and I explain how it identifies other forces selecting for
dispersal\r\nand puts them on a common scale.\r\nThird, I analyse genetic variances
of phenotypic traits under multivariate stabilizing\r\nselection. For the case
of constant environments, I generalize known formulae of\r\nequilibrium variances
to multiple traits and discuss how the genetic variance of a focal\r\ntrait is
influenced by selection on background traits. I conclude by presenting ideas and\r\npreliminary
work aiming at including environmental fluctuations in the form of moving\r\ntrait
optima into the model."
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Sebastian
full_name: Novak, Sebastian
id: 461468AE-F248-11E8-B48F-1D18A9856A87
last_name: Novak
orcid: 0000-0002-2519-824X
citation:
ama: Novak S. Evolutionary proccesses in variable emvironments. 2016.
apa: Novak, S. (2016). Evolutionary proccesses in variable emvironments.
Institute of Science and Technology Austria.
chicago: Novak, Sebastian. “Evolutionary Proccesses in Variable Emvironments.” Institute
of Science and Technology Austria, 2016.
ieee: S. Novak, “Evolutionary proccesses in variable emvironments,” Institute of
Science and Technology Austria, 2016.
ista: Novak S. 2016. Evolutionary proccesses in variable emvironments. Institute
of Science and Technology Austria.
mla: Novak, Sebastian. Evolutionary Proccesses in Variable Emvironments.
Institute of Science and Technology Austria, 2016.
short: S. Novak, Evolutionary Proccesses in Variable Emvironments, Institute of
Science and Technology Austria, 2016.
date_created: 2018-12-11T11:50:17Z
date_published: 2016-07-01T00:00:00Z
date_updated: 2023-09-07T11:55:53Z
day: '01'
ddc:
- '576'
degree_awarded: PhD
department:
- _id: NiBa
file:
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content_type: application/pdf
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language:
- iso: eng
month: '07'
oa: 1
oa_version: Published Version
page: '124'
publication_identifier:
issn:
- 2663-337X
publication_status: published
publisher: Institute of Science and Technology Austria
publist_id: '6235'
related_material:
record:
- id: '2023'
relation: part_of_dissertation
status: public
status: public
supervisor:
- first_name: Nicholas H
full_name: Barton, Nicholas H
id: 4880FE40-F248-11E8-B48F-1D18A9856A87
last_name: Barton
orcid: 0000-0002-8548-5240
title: Evolutionary proccesses in variable emvironments
type: dissertation
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
year: '2016'
...
---
_id: '1358'
abstract:
- lang: eng
text: 'Gene regulation relies on the specificity of transcription factor (TF)–DNA
interactions. Limited specificity may lead to crosstalk: a regulatory state in
which a gene is either incorrectly activated due to noncognate TF–DNA interactions
or remains erroneously inactive. As each TF can have numerous interactions with
noncognate cis-regulatory elements, crosstalk is inherently a global problem,
yet has previously not been studied as such. We construct a theoretical framework
to analyse the effects of global crosstalk on gene regulation. We find that crosstalk
presents a significant challenge for organisms with low-specificity TFs, such
as metazoans. Crosstalk is not easily mitigated by known regulatory schemes acting
at equilibrium, including variants of cooperativity and combinatorial regulation.
Our results suggest that crosstalk imposes a previously unexplored global constraint
on the functioning and evolution of regulatory networks, which is qualitatively
distinct from the known constraints that act at the level of individual gene regulatory
elements.'
article_number: '12307'
author:
- first_name: Tamar
full_name: Friedlander, Tamar
id: 36A5845C-F248-11E8-B48F-1D18A9856A87
last_name: Friedlander
- first_name: Roshan
full_name: Prizak, Roshan
id: 4456104E-F248-11E8-B48F-1D18A9856A87
last_name: Prizak
- first_name: Calin C
full_name: Guet, Calin C
id: 47F8433E-F248-11E8-B48F-1D18A9856A87
last_name: Guet
orcid: 0000-0001-6220-2052
- first_name: Nicholas H
full_name: Barton, Nicholas H
id: 4880FE40-F248-11E8-B48F-1D18A9856A87
last_name: Barton
orcid: 0000-0002-8548-5240
- first_name: Gasper
full_name: Tkacik, Gasper
id: 3D494DCA-F248-11E8-B48F-1D18A9856A87
last_name: Tkacik
orcid: 0000-0002-6699-1455
citation:
ama: Friedlander T, Prizak R, Guet CC, Barton NH, Tkačik G. Intrinsic limits to
gene regulation by global crosstalk. Nature Communications. 2016;7. doi:10.1038/ncomms12307
apa: Friedlander, T., Prizak, R., Guet, C. C., Barton, N. H., & Tkačik, G. (2016).
Intrinsic limits to gene regulation by global crosstalk. Nature Communications.
Nature Publishing Group. https://doi.org/10.1038/ncomms12307
chicago: Friedlander, Tamar, Roshan Prizak, Calin C Guet, Nicholas H Barton, and
Gašper Tkačik. “Intrinsic Limits to Gene Regulation by Global Crosstalk.” Nature
Communications. Nature Publishing Group, 2016. https://doi.org/10.1038/ncomms12307.
ieee: T. Friedlander, R. Prizak, C. C. Guet, N. H. Barton, and G. Tkačik, “Intrinsic
limits to gene regulation by global crosstalk,” Nature Communications,
vol. 7. Nature Publishing Group, 2016.
ista: Friedlander T, Prizak R, Guet CC, Barton NH, Tkačik G. 2016. Intrinsic limits
to gene regulation by global crosstalk. Nature Communications. 7, 12307.
mla: Friedlander, Tamar, et al. “Intrinsic Limits to Gene Regulation by Global Crosstalk.”
Nature Communications, vol. 7, 12307, Nature Publishing Group, 2016, doi:10.1038/ncomms12307.
short: T. Friedlander, R. Prizak, C.C. Guet, N.H. Barton, G. Tkačik, Nature Communications
7 (2016).
date_created: 2018-12-11T11:51:34Z
date_published: 2016-08-04T00:00:00Z
date_updated: 2023-09-07T12:53:49Z
day: '04'
ddc:
- '576'
department:
- _id: GaTk
- _id: NiBa
- _id: CaGu
doi: 10.1038/ncomms12307
ec_funded: 1
file:
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checksum: fe3f3a1526d180b29fe691ab11435b78
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creator: system
date_created: 2018-12-12T10:12:01Z
date_updated: 2020-07-14T12:44:46Z
file_id: '4919'
file_name: IST-2016-627-v1+1_ncomms12307.pdf
file_size: 861805
relation: main_file
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creator: system
date_created: 2018-12-12T10:12:02Z
date_updated: 2020-07-14T12:44:46Z
file_id: '4920'
file_name: IST-2016-627-v1+2_ncomms12307-s1.pdf
file_size: 1084703
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file_date_updated: 2020-07-14T12:44:46Z
has_accepted_license: '1'
intvolume: ' 7'
language:
- iso: eng
month: '08'
oa: 1
oa_version: Published Version
project:
- _id: 25681D80-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '291734'
name: International IST Postdoc Fellowship Programme
- _id: 25B07788-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '250152'
name: Limits to selection in biology and in evolutionary computation
- _id: 254E9036-B435-11E9-9278-68D0E5697425
call_identifier: FWF
grant_number: P28844-B27
name: Biophysics of information processing in gene regulation
publication: Nature Communications
publication_status: published
publisher: Nature Publishing Group
publist_id: '5887'
pubrep_id: '627'
quality_controlled: '1'
related_material:
record:
- id: '6071'
relation: dissertation_contains
status: public
scopus_import: 1
status: public
title: Intrinsic limits to gene regulation by global crosstalk
tmp:
image: /images/cc_by.png
legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
short: CC BY (4.0)
type: journal_article
user_id: 3E5EF7F0-F248-11E8-B48F-1D18A9856A87
volume: 7
year: '2016'
...
---
_id: '9710'
abstract:
- lang: eng
text: Much of quantitative genetics is based on the ‘infinitesimal model’, under
which selection has a negligible effect on the genetic variance. This is typically
justified by assuming a very large number of loci with additive effects. However,
it applies even when genes interact, provided that the number of loci is large
enough that selection on each of them is weak relative to random drift. In the
long term, directional selection will change allele frequencies, but even then,
the effects of epistasis on the ultimate change in trait mean due to selection
may be modest. Stabilising selection can maintain many traits close to their optima,
even when the underlying alleles are weakly selected. However, the number of traits
that can be optimised is apparently limited to ~4Ne by the ‘drift load’, and this
is hard to reconcile with the apparent complexity of many organisms. Just as for
the mutation load, this limit can be evaded by a particular form of negative epistasis.
A more robust limit is set by the variance in reproductive success. This suggests
that selection accumulates information most efficiently in the infinitesimal regime,
when selection on individual alleles is weak, and comparable with random drift.
A review of evidence on selection strength suggests that although most variance
in fitness may be because of alleles with large Nes, substantial amounts of adaptation
may be because of alleles in the infinitesimal regime, in which epistasis has
modest effects.
article_processing_charge: No
author:
- first_name: Nicholas H
full_name: Barton, Nicholas H
id: 4880FE40-F248-11E8-B48F-1D18A9856A87
last_name: Barton
orcid: 0000-0002-8548-5240
citation:
ama: 'Barton NH. Data from: How does epistasis influence the response to selection?
2016. doi:10.5061/dryad.s5s7r'
apa: 'Barton, N. H. (2016). Data from: How does epistasis influence the response
to selection? Dryad. https://doi.org/10.5061/dryad.s5s7r'
chicago: 'Barton, Nicholas H. “Data from: How Does Epistasis Influence the Response
to Selection?” Dryad, 2016. https://doi.org/10.5061/dryad.s5s7r.'
ieee: 'N. H. Barton, “Data from: How does epistasis influence the response to selection?”
Dryad, 2016.'
ista: 'Barton NH. 2016. Data from: How does epistasis influence the response to
selection?, Dryad, 10.5061/dryad.s5s7r.'
mla: 'Barton, Nicholas H. Data from: How Does Epistasis Influence the Response
to Selection? Dryad, 2016, doi:10.5061/dryad.s5s7r.'
short: N.H. Barton, (2016).
date_created: 2021-07-23T11:45:47Z
date_published: 2016-09-23T00:00:00Z
date_updated: 2023-09-20T11:17:47Z
day: '23'
department:
- _id: NiBa
doi: 10.5061/dryad.s5s7r
main_file_link:
- open_access: '1'
url: https://doi.org/10.5061/dryad.s5s7r
month: '09'
oa: 1
oa_version: Published Version
publisher: Dryad
related_material:
record:
- id: '1199'
relation: used_in_publication
status: public
status: public
title: 'Data from: How does epistasis influence the response to selection?'
type: research_data_reference
user_id: 6785fbc1-c503-11eb-8a32-93094b40e1cf
year: '2016'
...
---
_id: '9864'
abstract:
- lang: eng
text: Viral capsids are structurally constrained by interactions among the amino
acids (AAs) of their constituent proteins. Therefore, epistasis is expected to
evolve among physically interacting sites and to influence the rates of substitution.
To study the evolution of epistasis, we focused on the major structural protein
of the ϕX174 phage family by, first, reconstructing the ancestral protein sequences
of 18 species using a Bayesian statistical framework. The inferred ancestral reconstruction
differed at eight AAs, for a total of 256 possible ancestral haplotypes. For each
ancestral haplotype and the extant species, we estimated, in silico, the distribution
of free energies and epistasis of the capsid structure. We found that free energy
has not significantly increased but epistasis has. We decomposed epistasis up
to fifth order and found that higher-order epistasis sometimes compensates pairwise
interactions making the free energy seem additive. The dN/dS ratio is low, suggesting
strong purifying selection, and that structure is under stabilizing selection.
We synthesized phages carrying ancestral haplotypes of the coat protein gene and
measured their fitness experimentally. Our findings indicate that stabilizing
mutations can have higher fitness, and that fitness optima do not necessarily
coincide with energy minima.
article_processing_charge: No
author:
- first_name: Rodrigo A
full_name: Fernandes Redondo, Rodrigo A
id: 409D5C96-F248-11E8-B48F-1D18A9856A87
last_name: Fernandes Redondo
orcid: 0000-0002-5837-2793
- first_name: Harold
full_name: de Vladar, Harold
id: 2A181218-F248-11E8-B48F-1D18A9856A87
last_name: de Vladar
orcid: 0000-0002-5985-7653
- first_name: Tomasz
full_name: Włodarski, Tomasz
last_name: Włodarski
- first_name: Jonathan P
full_name: Bollback, Jonathan P
id: 2C6FA9CC-F248-11E8-B48F-1D18A9856A87
last_name: Bollback
orcid: 0000-0002-4624-4612
citation:
ama: Fernandes Redondo RA, de Vladar H, Włodarski T, Bollback JP. Data from evolutionary
interplay between structure, energy and epistasis in the coat protein of the ϕX174
phage family. 2016. doi:10.6084/m9.figshare.4315652.v1
apa: Fernandes Redondo, R. A., de Vladar, H., Włodarski, T., & Bollback, J.
P. (2016). Data from evolutionary interplay between structure, energy and epistasis
in the coat protein of the ϕX174 phage family. The Royal Society. https://doi.org/10.6084/m9.figshare.4315652.v1
chicago: Fernandes Redondo, Rodrigo A, Harold de Vladar, Tomasz Włodarski, and Jonathan
P Bollback. “Data from Evolutionary Interplay between Structure, Energy and Epistasis
in the Coat Protein of the ΦX174 Phage Family.” The Royal Society, 2016. https://doi.org/10.6084/m9.figshare.4315652.v1.
ieee: R. A. Fernandes Redondo, H. de Vladar, T. Włodarski, and J. P. Bollback, “Data
from evolutionary interplay between structure, energy and epistasis in the coat
protein of the ϕX174 phage family.” The Royal Society, 2016.
ista: Fernandes Redondo RA, de Vladar H, Włodarski T, Bollback JP. 2016. Data from
evolutionary interplay between structure, energy and epistasis in the coat protein
of the ϕX174 phage family, The Royal Society, 10.6084/m9.figshare.4315652.v1.
mla: Fernandes Redondo, Rodrigo A., et al. Data from Evolutionary Interplay between
Structure, Energy and Epistasis in the Coat Protein of the ΦX174 Phage Family.
The Royal Society, 2016, doi:10.6084/m9.figshare.4315652.v1.
short: R.A. Fernandes Redondo, H. de Vladar, T. Włodarski, J.P. Bollback, (2016).
date_created: 2021-08-10T08:29:47Z
date_published: 2016-12-14T00:00:00Z
date_updated: 2023-09-20T11:56:33Z
day: '14'
department:
- _id: NiBa
- _id: JoBo
doi: 10.6084/m9.figshare.4315652.v1
main_file_link:
- open_access: '1'
url: https://doi.org/10.6084/m9.figshare.4315652.v1
month: '12'
oa: 1
oa_version: Published Version
publisher: The Royal Society
related_material:
record:
- id: '1077'
relation: used_in_publication
status: public
status: public
title: Data from evolutionary interplay between structure, energy and epistasis in
the coat protein of the ϕX174 phage family
type: research_data_reference
user_id: 6785fbc1-c503-11eb-8a32-93094b40e1cf
year: '2016'
...
---
_id: '1382'
abstract:
- lang: eng
text: Background and aims Angiosperms display remarkable diversity in flower colour,
implying that transitions between pigmentation phenotypes must have been common.
Despite progress in understanding transitions between anthocyanin (blue, purple,
pink or red) and unpigmented (white) flowers, little is known about the evolutionary
patterns of flower-colour transitions in lineages with both yellow and anthocyanin-pigmented
flowers. This study investigates the relative rates of evolutionary transitions
between different combinations of yellow- and anthocyanin-pigmentation phenotypes
in the tribe Antirrhineae. Methods We surveyed taxonomic literature for data on
anthocyanin and yellow floral pigmentation for 369 species across the tribe. We
then reconstructed the phylogeny of 169 taxa and used phylogenetic comparative
methods to estimate transition rates among pigmentation phenotypes across the
phylogeny. Key Results In contrast to previous studies we found a bias towards
transitions involving a gain in pigmentation, although transitions to phenotypes
with both anthocyanin and yellow taxa are nevertheless extremely rare. Despite
the dominance of yellow and anthocyanin-pigmented taxa, transitions between these
phenotypes are constrained to move through a white intermediate stage, whereas
transitions to double-pigmentation are very rare. The most abundant transitions
are between anthocyanin-pigmented and unpigmented flowers, and similarly the most
abundant polymorphic taxa were those with anthocyanin-pigmented and unpigmented
flowers. Conclusions Our findings show that pigment evolution is limited by the
presence of other floral pigments. This interaction between anthocyanin and yellow
pigments constrains the breadth of potential floral diversity observed in nature.
In particular, they suggest that selection has repeatedly acted to promote the
spread of single-pigmented phenotypes across the Antirrhineae phylogeny. Furthermore,
the correlation between transition rates and polymorphism suggests that the forces
causing and maintaining variance in the short term reflect evolutionary processes
on longer time scales.
acknowledgement: We thank Melinda Pickup, Spencer Barrett, Nick Barton and four anonymous
reviewers for helpful discussions on previous versions of this manuscript. We also thank Jana Porsche for
her efforts in tracking down the more obscure references.
author:
- first_name: Thomas
full_name: Ellis, Thomas
id: 3153D6D4-F248-11E8-B48F-1D18A9856A87
last_name: Ellis
orcid: 0000-0002-8511-0254
- first_name: David
full_name: Field, David
id: 419049E2-F248-11E8-B48F-1D18A9856A87
last_name: Field
orcid: 0000-0002-4014-8478
citation:
ama: Ellis T, Field D. Repeated gains in yellow and anthocyanin pigmentation in
flower colour transitions in the Antirrhineae. Annals of Botany. 2016;117(7):1133-1140.
doi:10.1093/aob/mcw043
apa: Ellis, T., & Field, D. (2016). Repeated gains in yellow and anthocyanin
pigmentation in flower colour transitions in the Antirrhineae. Annals of Botany.
Oxford University Press. https://doi.org/10.1093/aob/mcw043
chicago: Ellis, Thomas, and David Field. “Repeated Gains in Yellow and Anthocyanin
Pigmentation in Flower Colour Transitions in the Antirrhineae.” Annals of Botany.
Oxford University Press, 2016. https://doi.org/10.1093/aob/mcw043.
ieee: T. Ellis and D. Field, “Repeated gains in yellow and anthocyanin pigmentation
in flower colour transitions in the Antirrhineae,” Annals of Botany, vol.
117, no. 7. Oxford University Press, pp. 1133–1140, 2016.
ista: Ellis T, Field D. 2016. Repeated gains in yellow and anthocyanin pigmentation
in flower colour transitions in the Antirrhineae. Annals of Botany. 117(7), 1133–1140.
mla: Ellis, Thomas, and David Field. “Repeated Gains in Yellow and Anthocyanin Pigmentation
in Flower Colour Transitions in the Antirrhineae.” Annals of Botany, vol.
117, no. 7, Oxford University Press, 2016, pp. 1133–40, doi:10.1093/aob/mcw043.
short: T. Ellis, D. Field, Annals of Botany 117 (2016) 1133–1140.
date_created: 2018-12-11T11:51:42Z
date_published: 2016-06-01T00:00:00Z
date_updated: 2024-02-21T13:49:53Z
day: '1'
department:
- _id: NiBa
doi: 10.1093/aob/mcw043
intvolume: ' 117'
issue: '7'
language:
- iso: eng
month: '06'
oa_version: None
page: 1133 - 1140
publication: Annals of Botany
publication_status: published
publisher: Oxford University Press
publist_id: '5828'
quality_controlled: '1'
related_material:
record:
- id: '5550'
relation: popular_science
status: public
scopus_import: 1
status: public
title: Repeated gains in yellow and anthocyanin pigmentation in flower colour transitions
in the Antirrhineae
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 117
year: '2016'
...