Tag Archives: population genetics

Why Soft Sweeps from Standing Genetic Variation are More Likely than You May Think

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We coined the term “soft sweeps” in 2005. The term has since become widely used, though not everyone uses the term in the same way. As part of the ‘How to Measure Natural Selection‘ Special Feature in Methods in Ecology and Evolution, we attempt to clarify what “soft sweep” means and doesn’t mean. For example, not every sweep from standing genetic variation is necessarily a soft sweep.
In the review paper we also show under what conditions soft sweeps are likely (e.g., high population-wide mutation rate, multi-locus selection target). Finally, we describe relevant examples in fruitflies, humans and microbes and we discuss future research directions.
The video focuses on one aspect of the paper, which is illustrated in figure 3: “Why soft sweeps from standing genetic variation are more likely than you may think.”

This video is based on the Open Access article ‘Soft sweeps and beyond: understanding the patterns and probabilities of selection footprints under rapid adaptation‘ by Hermisson and Pennings in the ‘How to Measure Natural Selection‘ Special Feature.

 

What silver fir aDNA can tell us about Neolithic forests

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Below is a press release about the Methods paper ‘HyRAD-X, a versatile method combining exome capture and RAD sequencing to extract genomic information from ancient DNA‘ taken from Swiss Federal Institute for Forest, Snow and Landscape Research WSL (this press release is also available in French, German and Italian via the links below).

A new technique makes it possible to cost-effectively analyse genetic material from fossil plants and animals. Researchers from the Swiss Federal Institute for Forest, Snow and Landscape Research WSL and the universities of Lausanne and Bern have used this technique to examine the DNA of silver fir remains found in lake sediment in Ticino. They found clues as to how forests reacted to the emergence of agriculture.

The new process utilises the latest advances in DNA technology to isolate ancient DNA (aDNA) from prehistoric plants and animals. The techniques used to date are, however, expensive. “As population geneticists often need several dozens samples to make reliable statements, many research ideas are not currently financially viable,” says Nadir Alvarez, a professor at the University of Lausanne’s Department of Ecology and Evolution.

The research team led by Alvarez and his colleagues Christoph Sperisen (a population geneticist at the WSL), Willy Tinner (a professor of palaeoecology at the University of Bern) and Sarah Schmid (a biologist from the University of Lausanne) has now developed a cost-effective alternative and demonstrated its potential with subfossil silver fir needles found at Origlio lake in Ticino. The team showcased the results in the research journal Methods in Ecology and Evolution. Continue reading →

Issue 8.2

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Issue 8.2 is now online!

The February issue of Methods is now online!

This issue contains four(!) Applications articles and two Open Access articles. These six papers are freely available to everyone – no subscription required.

– Earth Mover’s Distance: The Earth Mover’s Distance (or EMD) is a method commonly used in image retrieval applications. The authors of this paper propose its use to calculate similarity in space use in the framework of movement ecology. This will be helpful for many questions regarding behavioural ecology, wildlife management and conservation.

– warbleR: The R package warbleR is a new package for the analysis of animal acoustic signal structure. It offers functions for downloading avian vocalisations from the open-access online repository Xeno-Canto, displaying the geographic extent of the recordings, manipulating sound files, detecting acoustic signals or importing detected signals from other software, and much more.

– meteR: The open-source R package, meteR directly calculates all of Maximum entropy theory of ecology’s (METE’s) predictions from a variety of data formats; automatically handles approximations and other technical details; and provides high-level plotting and model comparison functions to explore and interrogate models.

– Noise Egg: The Noise Egg is a device that can produce a low-frequency sound, which can be used as an experimental source of noise both in aquaria and in the field. It was developed to study the effects of noise on communication and behaviour in small aquatic animals; however, it could be used for other purposes, such as testing the propagation of certain frequencies in shallow-water habitats.

Continue reading →

Issue 7.1

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Issue 7.1 is now online!

The January issue of Methods is now online!

As always, the first issue of the year is our sample issue. You can access all of the articles online free of charge. No subscription or membership is required!

We have two Open Access articles and two Applications papers in our January issue.

– Recognizing False Positives: Environmental DNA (eDNA) is increasingly used for surveillance and detection of species of interest in aquatic and soil samples. A significant risk associated with eDNA methods is potential false-positive results due to laboratory contamination. To minimize and quantify this risk, Chris Wilson et al. designed and validated a set of synthetic oligonucleotides for use as species-specific positive PCR controls for several high-profile aquatic invasive species.

– BiMat: An open-source MATLAB package for the study of the structure of bipartite ecological networks. BiMat enables both multiscale analysis of the structure of a bipartite ecological network – spanning global (i.e. entire network) to local (i.e. module-level) scales – and meta-analyses of many bipartite networks simultaneously. The authors have chosen to make this Applications article Open Access.

Gemma Murray et al. provide this month’s second Open Access article. In ‘The effect of genetic structure on molecular dating and tests for temporal signal‘ the authors use simulated data to investigate the performance of several tests of temporal signal, including some recently suggested modifications. The article shows that all of the standard tests of temporal signal are seriously misleading for data where temporal and genetic structures are confounded (i.e. where closely related sequences are more likely to have been sampled at similar times). This is not an artifact of genetic structure or tree shape per se, and can arise even when sequences have measurably evolved during the sampling period.

Our January issue also features articles on Monitoring, Population Ecology, Genetics, Evolution, Community Ecology, Diversity and more. Continue reading →

Issue 6.11

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Issue 6.11 is now online!

The November issue of Methods is now online!

This month’s issue contains two Applications articles and one Open Access article, all of which are freely available.

– mvMORPH: A package of multivariate phylogenetic comparative methods for the R statistical environment which allows fitting a range of multivariate evolutionary models under a maximum-likelihood criterion. Its use can be extended to any biological data set with one or multiple covarying continuous traits.

– Low-cost soil CO2 efflux and point concentration sensing systems: The authors use commercially available, low-cost and low-power non-dispersive infrared (NDIR) CO2 sensors to develop a soil CO2 efflux system and a point CO2 concentration system. Their methods enable terrestrial ecologists to substantially improve the characterization of CO2 fluxes and concentrations in heterogeneous environments.

This month’s Open Access article comes from Jolyon Troscianko and Martin Stevens. In ‘Image calibration and analysis toolbox – a free software suite for objectively measuring reflectance, colour and pattern‘ they introduce a toolbox that can convert images to correspond to the visual system (cone-catch values) of a wide range of animals, enabling human and non-human visual systems to be modelled. The toolbox is freely available as an addition to the open source ImageJ software and will considerably enhance the appropriate use of digital cameras across multiple areas of biology. In particular, researchers aiming to quantify animal and plant visual signals will find this useful. This article received some media attention upon Early View publication over the summer. You can read the Press Release about it here.

Our November issue also features articles on Population Genetics, Macroevolution, Modelling species turnover, Abundance modelling, Measuring stress and much more. Continue reading →

Associate Editor Profile: LOUISE JOHNSON

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Dr Louise Johnson, a population geneticist working on the evolution of genetic systems, has been an Associate Editor for Methods in Ecology and Evolution since October 2013. In that time she has handled a range of manuscripts falling within her areas of expertise (primarily molecular evolution, population genetics and genomes).

Louise Johnson

Dr Louise Johnson

Louise began her academic career with a degree in Genetics at the University of Edinburgh. She then moved south to complete her PhD on the evolution of mating systems in yeast at Imperial College London under the supervision of Professor Austin Burt. Following her successful time in London, she took up post-doctorate positions at the University of Nottingham (working on transposable elements with Professor John Brookfield) and across the Atlantic at the University of Virginia (looking at genome defences with Professor Janis Antonovics and Professor Michael Hood). Louise returned to the UK in 2006 to take up an RCUK Fellowship at the University of Reading and has been there ever since.

As part of our series of Editor Profiles, we asked Louise to tell us about some of her current research:

There are three projects which I am currently working on that I would like to outline. I’ll be discussing the cancer project – or at least the story so far – at the Methods in Ecology and Evolution 5th Anniversary Symposium later this month. Do check out the programme, and I hope to see you there! The whole point of a methods journal is to help each other do our research as well and easily as possible, so there’s a built-in community spirit about MEE, which bodes well for a fun and useful meeting. Before I start I should also say that I’m lucky to have amazing collaborators at Reading and beyond: for the projects below, credit is particularly due to my colleagues Rob Jackson and Tiffany Taylor, who had a huge input, and to Mike Brockhurst at York. Continue reading →

Recently accepted articles

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We have been very busy in the past couple of weeks and we have a whole range of recently accepted articles:

  • A novel digital telemetry system for tracking wild animals: a field test for studying mate choice in a lekking tropical bird
    Dan Mennill, Stéphanie Doucet, Kara-Anne Ward, Dugan Maynard, Brian Otis and John Burt
  • A general theory of multimetric indices and their properties
    Donald Schoolmaster, James Grace and E. Schweiger
  • Beyond sensitivity: nonlinear perturbation analysis of transient dynamics
    Iain Stott, Dave Hodgson, and Stuart Townley
  • A two-phase sampling design for increasing detection of rare species in occupancy surveys
    Krishna Pacifici, Robert Dorazio and Michael Conroy
  • Metabarcoding of arthropods for rapid biodiversity assessment and biomonitoring
    Douglas Yu, Yingiu Ji, Brent Emerson, Xiaoyang Wang, Chengxi Ye, Chunyan Yang and Zhaoli Ding
  • How to measure and test phylogenetic signal
    Tamara Münkemüller, Sébastien Lavergne, Bruno Bzeznik, Stéphane Dray, Thibaut Jombart, Katja Schiffers and Wilfried Thuiller
  • Statistical evaluation of parameters estimating autocorrelation and individual heterogeneity in longitudinal studies
    Sandra Hamel, Nigel Yoccoz and Jean-Michel Gaillard
  • jPopGen Suite: population genetics analysis of DNA polymorphism from nucleotide sequences with errors
    Xiaoming Liu

They will be soon available on Early View.

Evolution MegaLab

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Modern technology offers some really exciting new opportunities for the use of citizen science, and in our newest video Jonathan Silvertown, Open University, gives a demonstration of Evolution MegaLab, a huge collaboration exploring the use of citizen science methods to undertake high-quality surveys of polymorphism in a wild species.


Jonathan demonstrates the site’s display of historical polymorphism data, some features designed to enable researchers to assess the reliability of volunteer-gathered data, and the process by which anyone can add newly gathered data to the project database.

In a paper recently published in Methods, the authors detail  the methodology used in setting up the Evolution MegaLab, analyse its more and less successful components, and provide a clear set of guidelines for any designer of future citizen science projects.

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