Speaker: Dr. Andrea Dixon (Rothamsted)

Title: At the edge of the species: the effects of gene flow on fitness

Where: Medawar Building G02 Watson LT, UCL (Gower Street, London, WC1E 6BT)

When: 25th April 2017, 18:30

Abstract:

Species ranges that are distributed across environmentally heterogeneous landscapes can be constrained by the efficacy of natural selection at range edges. Constraints on adaptation in range edge populations may arise because of small effective population size or because of an antagonism between divergent selection and gene flow. Mimulus bicolor, is an herbaceous spring annual constrained to the Sierra Nevada Mountain range in California, USA. To understand if maladaptive gene flow or small effective population size limits the species’ range, we investigated if populations found at climatically divergent range edges and at the center of the range were locally adapted using a common garden experiment in climate-controlled chambers. We then assessed the consequences of gene flow into edge populations by comparing the fitness of hybrids to parents originating from the local edge environment. These common garden analyses were supported by coalescent analysis to estimate effective population size and gene flow between central and edge populations originating from the field. From the common garden experiment, our results suggest that the populations used in this study were not locally adapted and gene flow from central to edge populations increased hybrid fitness. In addition, edge populations were effectively smaller than central populations. Taken together, these results reject the hypothesis that the range limits reflect an antagonism between divergent selection and gene flow. The geographic distribution of M. bicolor, however, likely reflects the reduced efficacy of natural selection in effectively small populations inhabiting stressful range edge environments.

NEW!  Programme and abstracts book available here: lern2016_abstract_book.pdf

Our annual conference is coming up! Join us for a great day of discovering the great evolutionary research being done by fellow students and PostDocs from around London and beyond!

Please register here. If you’d like to submit an abstract for a 15 minute talk, lightning talk, or poster, please email us at contact@londonevolution.org.

As usual in the last few years, we have a theme for our keynote speakers: the Application of Evolutionary Principles to Agriculture and Medicine.

More information here.

When: 9th November 2016

Location: Fogg lecture theater, Queen Mary University

Cost: Free!

Accessibility: The Fogg Lecture Theatre is wheelchair-accessible. There is easy access to a wheelchair-accessible toilet.

Speaker: Dr. Camilla Power (University of East London)

Title: The Revolutionary Sex: can sexual conflict theory help explain the emergence of language and culture?

Where: UCL (South Wing 9 Garwood LT)

When: 12th October, 18:00

Abstract:

Across species, sexual selection and sexual conflict – where the evolutionary interests of the sexes differ – provide the arena for the evolution of highly elaborate forms of signaling. Sexual conflict models, with complex psychological adaptations to situations of both conflict and cooperation between the sexes, can illuminate the evolution of the human symbolic domain of language, art and ritual.

Inside the last half- million years, significant encephalization in our African ancestors imposed heavy reproductive costs on females. Female coalitionary ritualized display emerged as a strategy to increase levels of male investment in very large-brained offspring.  Basically, we’re here today with our huge brains because women (and investor males) won the symbolic revolution at the expense of non-investing alpha males. The advantage of this model is that it offers specific predictions about the symbolic signals that arose and can still be traced in the archaeological and ethnographic records.