Evolution 2018 Day 1: From genomics in the wild, to new models of selection

It’s Evolution conference time! Evolution has long been my favourite fixture in the conference calendar, with its diverse mix of theoretical and empirical studies that span the full range of evolutionary biology. This year it’s the second Joint Congress on Evolutionary Biology, which brings together the European Society for Evolutionary Biology, the American Society of Naturalists, the Society for the Study of Evolution and the Society of Systematic Biologists all under one roof in the lovely city of Montpellier in the south of France.

The conference kicks off with the ESEB Presidents’ Award delivered by Loeske Kruuk (Australian National University), with a talk entitled ‘Evolutionary dynamics and fitness in wild populations’. Studying quantitative genetics in the wild is challenging because many classical theoretical predictions don’t apply, and because robust inferences require long-term studies that genotype complete populations. Loeske discusses how her work generating a completely pedigree, along with large-scale phenotypic data, for the superb fairy-wren (Malurus cyaneus), has given insights into quantitative genetics in the wild. Interestingly she shows temporal covariance between body size and fitness, but this is because body size is related to other traits, and therefore there is no expectation of body size showing an evolutionary response. She also shows date of moult is heritable, and suggests this means that ‘the early bird gets the girl’. She finishes up by saying that there are less than 10 estimates of fitness for wild populations, and that there are some consistent effects between species (like cohort effects) but lots of variation. I’m really looking forward to seeing the paper where these comparisons of fitness are presented.

The superb fairy wren. Image JJ Harrison/Wikipedia.

Next up is the session ‘Consequences of hybridization: from swamping to speciation’, one of 78 thematic symposia in 13 parallel sessions. The highlight talk for me is Molly Schumer (Harvard University) discussing hybridisation in swordtail fishes. These remarkable fish all demonstrate over 10% hybrid ancestry in their genomes, suggesting a pervasive role of hybridisation in adaptation and speciation. She goes on to discuss how low coverage sequencing and local ancestry analyses reveal the minor parent ancestry being purged over time, as well as assortative mating related to hybrid ancestry. It’s a great demonstration of how fine-scale genomic analyses of independent geographic populations can reveal the repeatability of evolution. Other interesting talks in the session include Mario Vallejo-Marin (University of Stirling) discussing rapid evolution of hybrid monkeyflowers, and Amy Goldberg (Duke University) discussing global ancestry proportions inferred by mechanistic models.

The readily hybridising fish genus Xiphophorus. Image: Wikipedia.

After a lunch, I hop over to the session ‘Towards an integrated understanding of genomic and phenotypic divergence’. Thom Nelson (University of Montana) tell us how comparative genomic analyses of the monkeyflowers Mimulus lewisii and M. cardinalis show substantial genomic rearrangements, but with low divergence (as measured by Fst) and without elevated divergence in translocations and inversion. Konrad Lohse (who has the office next to me at the University of Edinburgh) gives a critical appraisal of verbal models of island of divergence, and discusses recent work to produce better genome scans for divergence. This talk seems particularly relevant given the widespread use of genome scans and the use of arbitrary cut-offs for outliers (something many of us have been guilty of at some point). Finally, David Field (IST Austria) gives an exciting overview of a hybrid zone between snapdragon (Antirrhinum) subspecies with contrasting flower colours. This study is an exceptional case of generating a pedigree of a plant population that incorporates all the complexities that occur in the wild (e.g. most Antirrhinum plants are annuals but 20% are perennial, and seeds can persist in the seedbank). These data reveal strong home-site advantage for the two subspecies, with strong clines for loci underlying flower colour in the hybrid zone.

The first day really shows the breadth of evolutionary research. Evolutionary biologist no longer appear to be getting dazzled by new technology (only one photo of a sequencer today) and genomic sequencing is now just a routine tool for investigating evolutionary questions. It’s also been nice to see such a well-organised conference, with clear cut-offs for talks to prevent people overrunning (using an interesting choice of music!), facilities for childcare, and minimal use of disposable materials.

Please let me your favourite moments of Evolution 2018 via Twitter (@alex_twyford) and I’ll include a selection in a conference round-up post once the conference dinner hangover eases.

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About Alex Twyford

Alex Twyford is a Research Fellow at the University of Edinburgh, and a Research Associate at the Royal Botanic Garden Edinburgh. He studies the ecology and evolution of plants. Twitter @alex_twyford.
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