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Hagan T, Ding G, Buchmann G, Oldroyd BP, Gloag R. Serial founder effects slow range expansion in an invasive social insect. Nat Commun 2024; 15:3608. [PMID: 38684711 PMCID: PMC11058855 DOI: 10.1038/s41467-024-47894-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2023] [Accepted: 04/10/2024] [Indexed: 05/02/2024] Open
Abstract
Invasive populations often experience founder effects: a loss of genetic diversity relative to the source population, due to a small number of founders. Even where these founder effects do not impact colonization success, theory predicts they might affect the rate at which invasive populations expand. This is because secondary founder effects are generated at advancing population edges, further reducing local genetic diversity and elevating genetic load. We show that in an expanding invasive population of the Asian honey bee (Apis cerana), genetic diversity is indeed lowest at range edges, including at the complementary sex determiner, csd, a locus that is homozygous-lethal. Consistent with lower local csd diversity, range edge colonies had lower brood viability than colonies in the range centre. Further, simulations of a newly-founded and expanding honey bee population corroborate the spatial patterns in mean colony fitness observed in our empirical data and show that such genetic load at range edges will slow the rate of population expansion.
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Affiliation(s)
- Thomas Hagan
- Behaviour, Ecology and Evolution Lab, School of Life and Environmental Sciences, University of Sydney, Sydney, NSW, 2006, Australia.
| | - Guiling Ding
- Behaviour, Ecology and Evolution Lab, School of Life and Environmental Sciences, University of Sydney, Sydney, NSW, 2006, Australia
- Key Laboratory of Pollinating Insect Biology of the Ministry of Agriculture and Rural Affairs, Institute of Apicultural Research, Chinese Academy of Agricultural Sciences, Beijing, 100093, China
| | - Gabriele Buchmann
- Behaviour, Ecology and Evolution Lab, School of Life and Environmental Sciences, University of Sydney, Sydney, NSW, 2006, Australia
| | - Benjamin P Oldroyd
- Behaviour, Ecology and Evolution Lab, School of Life and Environmental Sciences, University of Sydney, Sydney, NSW, 2006, Australia
| | - Rosalyn Gloag
- Behaviour, Ecology and Evolution Lab, School of Life and Environmental Sciences, University of Sydney, Sydney, NSW, 2006, Australia.
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Hall R, Bandara A, Charlebois DA. Fitness effects of a demography-dispersal trade-off in expanding Saccharomyces cerevisiaemats. Phys Biol 2024; 21:026001. [PMID: 38194907 DOI: 10.1088/1478-3975/ad1ccd] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 01/09/2024] [Indexed: 01/11/2024]
Abstract
Fungi expand in space and time to form complex multicellular communities. The mechanisms by which they do so can vary dramatically and determine the life-history and dispersal traits of expanding populations. These traits influence deterministic and stochastic components of evolution, resulting in complex eco-evolutionary dynamics during colony expansion. We perform experiments on budding yeast strains genetically engineered to display rough-surface and smooth-surface phenotypes in colony-like structures called 'mats'. Previously, it was shown that the rough-surface strain has a competitive advantage over the smooth-surface strain when grown on semi-solid media. We experimentally observe the emergence and expansion of segments with a distinct smooth-surface phenotype during rough-surface mat development. We propose a trade-off between dispersal and local carrying capacity to explain the relative fitness of these two phenotypes. Using a modified stepping-stone model, we demonstrate that this trade-off gives the high-dispersing, rough-surface phenotype a competitive advantage from standing variation, but that it inhibits this phenotype's ability to invade a resident smooth-surface population via mutation. However, the trade-off improves the ability of the smooth-surface phenotype to invade in rough-surface mats, replicating the frequent emergence of smooth-surface segments in experiments. Together, these computational and experimental findings advance our understanding of the complex eco-evolutionary dynamics of fungal mat expansion.
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Affiliation(s)
- Rebekah Hall
- Department of Mathematical and Statistical Sciences, University of Alberta, 11455 Saskatchewan Drive NW, Edmonton, Alberta, Canada
| | - Akila Bandara
- Department of Physics, University of Alberta, 11455 Saskatchewan Drive NW, Edmonton, Alberta, Canada
| | - Daniel A Charlebois
- Department of Physics, University of Alberta, 11455 Saskatchewan Drive NW, Edmonton, Alberta, Canada
- Department of Biological Sciences, University of Alberta, 11455 Saskatchewan Drive NW, Edmonton, Alberta, Canada
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Olofsson P, Chipkin L, Daileda RC, Azevedo RBR. Mutational meltdown in asexual populations doomed to extinction. J Math Biol 2023; 87:88. [PMID: 37994999 DOI: 10.1007/s00285-023-02019-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 07/03/2023] [Accepted: 10/20/2023] [Indexed: 11/24/2023]
Abstract
Asexual populations are expected to accumulate deleterious mutations through a process known as Muller's ratchet. Lynch and colleagues proposed that the ratchet eventually results in a vicious cycle of mutation accumulation and population decline that drives populations to extinction. They called this phenomenon mutational meltdown. Here, we analyze mutational meltdown using a multi-type branching process model where, in the presence of mutation, populations are doomed to extinction. We analyse the change in size and composition of the population and the time of extinction under this model.
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Affiliation(s)
- Peter Olofsson
- Department of Mathematics, Trinity University, San Antonio, TX, 78212, USA
- Department of Mathematics, Physics and Chemical Engineering, Jönköping University, 551 11, Jönköping, Sweden
| | - Logan Chipkin
- Department of Biology and Biochemistry, University of Houston, Houston, TX, 77204, USA
| | - Ryan C Daileda
- Department of Mathematics, Trinity University, San Antonio, TX, 78212, USA
| | - Ricardo B R Azevedo
- Department of Biology and Biochemistry, University of Houston, Houston, TX, 77204, USA.
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North HL, McGaughran A, Jiggins CD. Insights into invasive species from whole-genome resequencing. Mol Ecol 2021; 30:6289-6308. [PMID: 34041794 DOI: 10.1111/mec.15999] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 03/12/2021] [Accepted: 04/30/2021] [Indexed: 12/12/2022]
Abstract
Studies of invasive species can simultaneously inform management strategies and quantify rapid evolution in the wild. The role of genomics in invasion science is increasingly recognised, and the growing availability of reference genomes for invasive species is paving the way for whole-genome resequencing studies in a wide range of systems. Here, we survey the literature to assess the application of whole-genome resequencing data in invasion biology. For some applications, such as the reconstruction of invasion routes in time and space, sequencing the whole genome of many individuals can increase the accuracy of existing methods. In other cases, population genomic approaches such as haplotype analysis can permit entirely new questions to be addressed and new technologies applied. To date whole-genome resequencing has only been used in a handful of invasive systems, but these studies have confirmed the importance of processes such as balancing selection and hybridization in allowing invasive species to reuse existing adaptations and rapidly overcome the challenges of a foreign ecosystem. The use of genomic data does not constitute a paradigm shift per se, but by leveraging new theory, tools, and technologies, population genomics can provide unprecedented insight into basic and applied aspects of invasion science.
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Affiliation(s)
- Henry L North
- Department of Zoology, University of Cambridge, Cambridge, UK
| | - Angela McGaughran
- Te Aka Mātuatua/School of Science, University of Waikato, Hamilton, New Zealand
| | - Chris D Jiggins
- Department of Zoology, University of Cambridge, Cambridge, UK
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Castillo D, Lavrentovich MO. Shape of population interfaces as an indicator of mutational instability in coexisting cell populations. Phys Biol 2020; 17:066002. [PMID: 33210619 DOI: 10.1088/1478-3975/abb2dd] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Cellular populations such as avascular tumors and microbial biofilms may 'invade' or grow into surrounding populations. The invading population is often comprised of a heterogeneous mixture of cells with varying growth rates. The population may also exhibit mutational instabilities, such as a heavy deleterious mutation load in a cancerous growth. We study the dynamics of a heterogeneous, mutating population competing with a surrounding homogeneous population, as one might find in a cancerous invasion of healthy tissue. We find that the shape of the population interface serves as an indicator for the evolutionary dynamics within the heterogeneous population. In particular, invasion front undulations become enhanced when the invading population is near a mutational meltdown transition or when the surrounding 'bystander' population is barely able to reinvade the mutating population. We characterize these interface undulations and the effective fitness of the heterogeneous population in one- and two-dimensional systems.
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Affiliation(s)
- Daniel Castillo
- Department of Physics & Astronomy, University of Tennessee, Knoxville, Tennessee 37996, United States of America
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