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Relaxed Selection During a Recent Human Expansion.

  • Peischl S Computational and Molecular Population Genetics Laboratory, Institute of Ecology and Evolution, University of Berne, 3012, Switzerland stephan.peischl@bioinformatics.unibe.ch laurent.excoffier@iee.unibe.ch.
  • Dupanloup I Computational and Molecular Population Genetics Laboratory, Institute of Ecology and Evolution, University of Berne, 3012, Switzerland.
  • Foucal A Computational and Molecular Population Genetics Laboratory, Institute of Ecology and Evolution, University of Berne, 3012, Switzerland.
  • Jomphe M Balsac Project, University of Quebec at Chicoutimi, Saguenay, Quebec, G7H 2B1 Canada.
  • Bruat V Hôpital Ste-Justine, University of Montréal, Quebec H3T1C5, Canada.
  • Grenier JC Hôpital Ste-Justine, University of Montréal, Quebec H3T1C5, Canada.
  • Gouy A Computational and Molecular Population Genetics Laboratory, Institute of Ecology and Evolution, University of Berne, 3012, Switzerland.
  • Gilbert KJ Computational and Molecular Population Genetics Laboratory, Institute of Ecology and Evolution, University of Berne, 3012, Switzerland.
  • Gbeha E Hôpital Ste-Justine, University of Montréal, Quebec H3T1C5, Canada.
  • Bosshard L Computational and Molecular Population Genetics Laboratory, Institute of Ecology and Evolution, University of Berne, 3012, Switzerland.
  • Hip-Ki E Hôpital Ste-Justine, University of Montréal, Quebec H3T1C5, Canada.
  • Agbessi M Hôpital Ste-Justine, University of Montréal, Quebec H3T1C5, Canada.
  • Hodgkinson A Hôpital Ste-Justine, University of Montréal, Quebec H3T1C5, Canada.
  • Vézina H Balsac Project, University of Quebec at Chicoutimi, Saguenay, Quebec, G7H 2B1 Canada.
  • Awadalla P Hôpital Ste-Justine, University of Montréal, Quebec H3T1C5, Canada.
  • Excoffier L Computational and Molecular Population Genetics Laboratory, Institute of Ecology and Evolution, University of Berne, 3012, Switzerland stephan.peischl@bioinformatics.unibe.ch laurent.excoffier@iee.unibe.ch.
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  • 2017-12-01
Published in:
  • Genetics. - 2018
Quebec
genetic drift
mutation load
range expansion
Algorithms
Alleles
Biological Evolution
Computer Simulation
Demography
Evolution, Molecular
Gene Frequency
Gene Ontology
Genetic Fitness
Genetic Variation
Genetics, Population
Humans
Models, Genetic
Mutation
Polymorphism, Single Nucleotide
Quebec
Selection, Genetic
English Humans have colonized the planet through a series of range expansions, which deeply impacted genetic diversity in newly settled areas and potentially increased the frequency of deleterious mutations on expanding wave fronts. To test this prediction, we studied the genomic diversity of French Canadians who colonized Quebec in the 17th century. We used historical information and records from ∼4000 ascending genealogies to select individuals whose ancestors lived mostly on the colonizing wave front and individuals whose ancestors remained in the core of the settlement. Comparison of exomic diversity reveals that: (i) both new and low-frequency variants are significantly more deleterious in front than in core individuals, (ii) equally deleterious mutations are at higher frequencies in front individuals, and (iii) front individuals are two times more likely to be homozygous for rare very deleterious mutations present in Europeans. These differences have emerged in the past six to nine generations and cannot be explained by differential inbreeding, but are consistent with relaxed selection mainly due to higher rates of genetic drift on the wave front. Demographic inference and modeling of the evolution of rare variants suggest lower effective size on the front, and lead to an estimation of selection coefficients that increase with conservation scores. Even though range expansions have had a relatively limited impact on the overall fitness of French Canadians, they could explain the higher prevalence of recessive genetic diseases in recently settled regions of Quebec.
Language
  • English
Open access status
bronze
Identifiers
Persistent URL
https://sonar.ch/global/documents/155557
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