---
_id: '12521'
abstract:
- lang: eng
text: Differentiated X chromosomes are expected to have higher rates of adaptive
divergence than autosomes, if new beneficial mutations are recessive (the “faster-X
effect”), largely because these mutations are immediately exposed to selection
in males. The evolution of X chromosomes after they stop recombining in males,
but before they become hemizygous, has not been well explored theoretically. We
use the diffusion approximation to infer substitution rates of beneficial and
deleterious mutations under such a scenario. Our results show that selection is
less efficient on diploid X loci than on autosomal and hemizygous X loci under
a wide range of parameters. This “slower-X” effect is stronger for genes affecting
primarily (or only) male fitness, and for sexually antagonistic genes. These unusual
dynamics suggest that some of the peculiar features of X chromosomes, such as
the differential accumulation of genes with sex-specific functions, may start
arising earlier than previously appreciated.
acknowledgement: We thank the Vicoso and Barton groups and ISTA Scientific Computing
Unit. We also thank two anonymous reviewers for their valuable comments. This work
was supported by the European Research Council under the European Union’s Horizon
2020 research and innovation program (grant agreements no. 715257 and no. 716117).
article_number: qrac004
article_processing_charge: Yes (via OA deal)
article_type: original
author:
- first_name: Andrea
full_name: Mrnjavac, Andrea
id: 353FAC84-AE61-11E9-8BFC-00D3E5697425
last_name: Mrnjavac
- first_name: Kseniia
full_name: Khudiakova, Kseniia
id: 4E6DC800-AE37-11E9-AC72-31CAE5697425
last_name: Khudiakova
orcid: 0000-0002-6246-1465
- 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: Beatriz
full_name: Vicoso, Beatriz
id: 49E1C5C6-F248-11E8-B48F-1D18A9856A87
last_name: Vicoso
orcid: 0000-0002-4579-8306
citation:
ama: 'Mrnjavac A, Khudiakova K, Barton NH, Vicoso B. Slower-X: Reduced efficiency
of selection in the early stages of X chromosome evolution. Evolution Letters.
2023;7(1). doi:10.1093/evlett/qrac004'
apa: 'Mrnjavac, A., Khudiakova, K., Barton, N. H., & Vicoso, B. (2023). Slower-X:
Reduced efficiency of selection in the early stages of X chromosome evolution.
Evolution Letters. Oxford University Press. https://doi.org/10.1093/evlett/qrac004'
chicago: 'Mrnjavac, Andrea, Kseniia Khudiakova, Nicholas H Barton, and Beatriz Vicoso.
“Slower-X: Reduced Efficiency of Selection in the Early Stages of X Chromosome
Evolution.” Evolution Letters. Oxford University Press, 2023. https://doi.org/10.1093/evlett/qrac004.'
ieee: 'A. Mrnjavac, K. Khudiakova, N. H. Barton, and B. Vicoso, “Slower-X: Reduced
efficiency of selection in the early stages of X chromosome evolution,” Evolution
Letters, vol. 7, no. 1. Oxford University Press, 2023.'
ista: 'Mrnjavac A, Khudiakova K, Barton NH, Vicoso B. 2023. Slower-X: Reduced efficiency
of selection in the early stages of X chromosome evolution. Evolution Letters.
7(1), qrac004.'
mla: 'Mrnjavac, Andrea, et al. “Slower-X: Reduced Efficiency of Selection in the
Early Stages of X Chromosome Evolution.” Evolution Letters, vol. 7, no.
1, qrac004, Oxford University Press, 2023, doi:10.1093/evlett/qrac004.'
short: A. Mrnjavac, K. Khudiakova, N.H. Barton, B. Vicoso, Evolution Letters 7 (2023).
date_created: 2023-02-06T13:59:12Z
date_published: 2023-02-01T00:00:00Z
date_updated: 2023-08-16T11:44:32Z
day: '01'
ddc:
- '570'
department:
- _id: GradSch
- _id: BeVi
doi: 10.1093/evlett/qrac004
ec_funded: 1
external_id:
isi:
- '001021692200001'
pmid:
- '37065438'
file:
- access_level: open_access
checksum: a240a041cb9b9b7c8ba93a4706674a3f
content_type: application/pdf
creator: dernst
date_created: 2023-08-16T11:43:33Z
date_updated: 2023-08-16T11:43:33Z
file_id: '14068'
file_name: 2023_EvLetters_Mrnjavac.pdf
file_size: 2592189
relation: main_file
success: 1
file_date_updated: 2023-08-16T11:43:33Z
has_accepted_license: '1'
intvolume: ' 7'
isi: 1
issue: '1'
keyword:
- Genetics
- Ecology
- Evolution
- Behavior and Systematics
language:
- iso: eng
license: https://creativecommons.org/licenses/by/4.0/
month: '02'
oa: 1
oa_version: Published Version
pmid: 1
project:
- _id: 256E75B8-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '716117'
name: Optimal Transport and Stochastic Dynamics
- _id: 250BDE62-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '715257'
name: Prevalence and Influence of Sexual Antagonism on Genome Evolution
publication: Evolution Letters
publication_identifier:
issn:
- 2056-3744
publication_status: published
publisher: Oxford University Press
quality_controlled: '1'
scopus_import: '1'
status: public
title: 'Slower-X: Reduced efficiency of selection in the early stages of X chromosome
evolution'
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: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 7
year: '2023'
...
---
_id: '9917'
abstract:
- lang: eng
text: Adaptive divergence and speciation may happen despite opposition by gene flow.
Identifying the genomic basis underlying divergence with gene flow is a major
task in evolutionary genomics. Most approaches (e.g., outlier scans) focus on
genomic regions of high differentiation. However, not all genomic architectures
potentially underlying divergence are expected to show extreme differentiation.
Here, we develop an approach that combines hybrid zone analysis (i.e., focuses
on spatial patterns of allele frequency change) with system-specific simulations
to identify loci inconsistent with neutral evolution. We apply this to a genome-wide
SNP set from an ideally suited study organism, the intertidal snail Littorina
saxatilis, which shows primary divergence between ecotypes associated with different
shore habitats. We detect many SNPs with clinal patterns, most of which are consistent
with neutrality. Among non-neutral SNPs, most are located within three large putative
inversions differentiating ecotypes. Many non-neutral SNPs show relatively low
levels of differentiation. We discuss potential reasons for this pattern, including
loose linkage to selected variants, polygenic adaptation and a component of balancing
selection within populations (which may be expected for inversions). Our work
is in line with theory predicting a role for inversions in divergence, and emphasizes
that genomic regions contributing to divergence may not always be accessible with
methods purely based on allele frequency differences. These conclusions call for
approaches that take spatial patterns of allele frequency change into account
in other systems.
acknowledgement: We are very grateful to people who helped with fieldwork, snail processing,
and DNA extractions, particularly Laura Brettell, Mårten Duvetorp, Juan Galindo,
Anne-Lise Liabot and Irena Senčić. We would also like to thank Magnus Alm Rosenblad
and Mats Töpel for their contribution to assembling the Littorina saxatilis genome,
Carl André, Pasi Rastas, and Romain Villoutreix for discussion, and two anonymous
reviewers for their helpful comments on the manuscript. We are grateful to RapidGenomics
for library preparation and sequencing. We thank the Natural Environment Research
Council, the European Research Council and the Swedish Research Councils VR and
Formas (Linnaeus grant to the Centre for Marine Evolutionary Biology and Tage Erlander
Guest Professorship) for funding. P.C. was funded by the University of Sheffield
Vice-chancellor's India scholarship. R.F. is funded by the European Union's Horizon
2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement
no. 706376. M. Raf. was supported by the Adlerbert Research Foundation.
article_processing_charge: Yes
article_type: letter_note
author:
- first_name: Anja M
full_name: Westram, Anja M
id: 3C147470-F248-11E8-B48F-1D18A9856A87
last_name: Westram
orcid: 0000-0003-1050-4969
- first_name: Marina
full_name: Rafajlović, Marina
last_name: Rafajlović
- first_name: Pragya
full_name: Chaube, Pragya
last_name: Chaube
- first_name: Rui
full_name: Faria, Rui
last_name: Faria
- first_name: Tomas
full_name: Larsson, Tomas
last_name: Larsson
- first_name: Marina
full_name: Panova, Marina
last_name: Panova
- first_name: Mark
full_name: Ravinet, Mark
last_name: Ravinet
- first_name: Anders
full_name: Blomberg, Anders
last_name: Blomberg
- first_name: Bernhard
full_name: Mehlig, Bernhard
last_name: Mehlig
- first_name: Kerstin
full_name: Johannesson, Kerstin
last_name: Johannesson
- first_name: Roger
full_name: Butlin, Roger
last_name: Butlin
citation:
ama: 'Westram AM, Rafajlović M, Chaube P, et al. Clines on the seashore: The genomic
architecture underlying rapid divergence in the face of gene flow. Evolution
Letters. 2018;2(4):297-309. doi:10.1002/evl3.74'
apa: 'Westram, A. M., Rafajlović, M., Chaube, P., Faria, R., Larsson, T., Panova,
M., … Butlin, R. (2018). Clines on the seashore: The genomic architecture underlying
rapid divergence in the face of gene flow. Evolution Letters. Wiley. https://doi.org/10.1002/evl3.74'
chicago: 'Westram, Anja M, Marina Rafajlović, Pragya Chaube, Rui Faria, Tomas Larsson,
Marina Panova, Mark Ravinet, et al. “Clines on the Seashore: The Genomic Architecture
Underlying Rapid Divergence in the Face of Gene Flow.” Evolution Letters.
Wiley, 2018. https://doi.org/10.1002/evl3.74.'
ieee: 'A. M. Westram et al., “Clines on the seashore: The genomic architecture
underlying rapid divergence in the face of gene flow,” Evolution Letters,
vol. 2, no. 4. Wiley, pp. 297–309, 2018.'
ista: 'Westram AM, Rafajlović M, Chaube P, Faria R, Larsson T, Panova M, Ravinet
M, Blomberg A, Mehlig B, Johannesson K, Butlin R. 2018. Clines on the seashore:
The genomic architecture underlying rapid divergence in the face of gene flow.
Evolution Letters. 2(4), 297–309.'
mla: 'Westram, Anja M., et al. “Clines on the Seashore: The Genomic Architecture
Underlying Rapid Divergence in the Face of Gene Flow.” Evolution Letters,
vol. 2, no. 4, Wiley, 2018, pp. 297–309, doi:10.1002/evl3.74.'
short: A.M. Westram, M. Rafajlović, P. Chaube, R. Faria, T. Larsson, M. Panova,
M. Ravinet, A. Blomberg, B. Mehlig, K. Johannesson, R. Butlin, Evolution Letters
2 (2018) 297–309.
date_created: 2021-08-16T07:45:38Z
date_published: 2018-08-20T00:00:00Z
date_updated: 2023-09-19T15:08:25Z
day: '20'
ddc:
- '570'
department:
- _id: BeVi
doi: 10.1002/evl3.74
external_id:
isi:
- '000446774400004'
pmid:
- '30283683'
file:
- access_level: open_access
checksum: 8524e72507d521416be3f8ccfcd5e3f5
content_type: application/pdf
creator: asandaue
date_created: 2021-08-16T07:48:03Z
date_updated: 2021-08-16T07:48:03Z
file_id: '9918'
file_name: 2018_EvolutionLetters_Westram.pdf
file_size: 764299
relation: main_file
success: 1
file_date_updated: 2021-08-16T07:48:03Z
has_accepted_license: '1'
intvolume: ' 2'
isi: 1
issue: '4'
language:
- iso: eng
month: '08'
oa: 1
oa_version: Published Version
page: 297-309
pmid: 1
publication: Evolution Letters
publication_identifier:
eissn:
- 2056-3744
issn:
- 2056-3744
publication_status: published
publisher: Wiley
quality_controlled: '1'
related_material:
record:
- id: '9930'
relation: research_data
status: public
status: public
title: 'Clines on the seashore: The genomic architecture underlying rapid divergence
in the face of gene flow'
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: c635000d-4b10-11ee-a964-aac5a93f6ac1
volume: 2
year: '2018'
...