Evolutionary dynamics in regions of low recombination

Revisiting old ideas in the light of genomic data

Transmissão através de Videoconferência

Por Stephan Peischl (University of Bern).

A common assumption in many population genetics models is that mutations evolve independently of each other. While this is often assumed for mathematical or statistical convenience, it is a valid approximation if the rate of recombination between mutational targets is sufficiently high. However, in many sexually reproducing organisms, there is substantial variation in recombination rate across the genome. Mutations that fall into regions of low recombination are strongly linked to the genomic background in their immediate neighborhood. One can thus think of the genome as the environmental conditions that modulate the fitness effect of new mutations, and the recombination rate as the rate at which different genomic environments are encountered. In this talk I will present two theoretical models, motivated by recent genomic data, in which reduced recombination can lead to interactions between mutations that alter nature and direction of natural selection. (i) We found that selection against recessive deleterious mutations in regions of low recombination can lead to elevated levels of diversity in genomes. This is in contrast to what is expected from positive or negative (background) selection, where we generally expect a positive correlation with recombination rate and diversity. This is due to pseudo-overdominance, which maintains complementary haplotypes at intermediate frequencies to mask the effects of deleterious mutations. We derive the conditions for this to occur in a multi-locus model and identify potential exemplary regions in the human genome. (ii) We model the establishment of clines that occur due to the surfing of underdominant alleles during range expansions. We provide analytical approximations for the fixation probability of underdominant alleles at expansion fronts and demonstrate that gene surfing can lead to clines in 1D range expansions. We then study the interaction between the strength of selection against heterozygotes migration rates and local recombination rates on the formation of stable hybrid zones at multiple loci. Clines created by surfing at different loci can attract each other and align after expansion if they are sufficiently close in space and in terms of recombination distance. Our findings suggest that range expansions can set the stage for parapatric speciation due to the alignment of multiple selective clines even in the absence of ecologically divergent selection.

Transmissão em direto via Zoom.

cE3c - Centro de Ecologia, Evolução e Alterações Ambientais

The objective of this course is to introduce participants to the details of communication and writing scientific publications.

Seminário de Lógica Matemática, por Bruno Jacinto (Universidade de Lisboa).

Seminário Permanente de Filosofia das Ciências, por Anna Ciaunica (CFCUL/GI2).

Seminário de Formação Avançada em Jardins, Paisagens e Ambiente, por Daniela Araújo e Mauro Nascimento (Museu de Lisboa | EGEAC).

Logótipo do evento, sobre um fundo branco

A iniciativa conta com o apoio do Centro Interuniversitário de História das Ciências e da Tecnologia.

Seminário conjunto do Centro de Estatística e Aplicações da Universidade de Lisboa e do Centro de Matemática Computacional e Estocástica, por Kristen Campbell (University of Colorado Anschutz Medical Campus, USA).

Research at the Faculty of Sciences

Participation is free but prior registration is suggested.

Encontro Scientia, por Rui A. P. Perdigão (EChanges - Chair Professor and Head of the Met Institute for Complex System Science, Vienna, Austria / NORA Climate Dynamics and Complexity Chair, Vienna, Austria & Princeton NJ USA / CCIAM coordinator at cE3c, Lisboa, Portugal).

Hi-Phi Seminar, por Nathalie Gontier (Ciências ULisboa, CFCUL) e Luís Tirapicos (Ciências ULisboa, CIUCHT).

Geometry Webinar, por Giosuè Muratore (CMAFcIO).

Conversa com Galopim de Carvalho.

Logótipo da IAESTE, sobre uma fotografia da cidade de Edimburgo

Candidaturas online de 01 a 31 de outubro 2021.

Imagem alusiva ao Concerto e Conferência

Concerto e conferência pela Orquestra Metropolitana de Lisboa.

Encontro Scientia, por Maria Amélia Martins Loução (PSE - cE3c).

Imagem ilustrativa do programa, acompanhada do respetivo título

Um programa de aceleração de ideias e negócios, promovido pela redeSaúde, com candidaturas até 15 de outubro de 2021.

Conversa com Galopim de Carvalho.

The objective of this course is to introduce participants to the details of communicating science to non-specialized audiences, including, but not exclusive to, public and private stakeholders, students and teachers, and media professionals.

Conversa com Galopim de Carvalho.

The course aims at providing an introduction to stable isotopes ratios as tools to understand global, ecosystem and community level bio/geo cycles; light isotopes: H, N, C, O and S isotopes, geo cycles and ecological significance; sampling and analytical methodologies in stable isotope analysis.

This course aims to evidence the importance of natural history collections for the study of biodiversity, to show new tools and approaches to extract and disseminate biodiversity data from natural history collections and to increase awareness of young researchers for the scientific and cultural value of Natural History Museums.

Conversa com Galopim de Carvalho.

EvoS aims at turning evolutionary theory into a common language to areas that pertain to the natural world, including human affairs.

Conversa com Galopim de Carvalho.

Fotografia de plantas

Pre-proposals submission until 30 November 2021, 15:00 CET(local time in Brussels).

O evento tem como tema central o "Conhecimento ao serviço das áreas classificadas" e marca o seu regresso ao formato presencial, mas com a possibilidade de participação online!