Talks

Most adaptive traits are polygenic with many underlying loci. The genetic architecture of these traits specifies how the phenotypes can be changed by mutations, but many factors determine which of these loci will be used during adaptation. Additionally, adaptation of complex traits in replicate populations with phenotypic convergence can occur through selection of different sets of loci. The analysis of time-series phenotypic and genomic data in replicates of evolving populations is crucial for understanding the adaptive architecture of a trait. I will demonstrate how experimental evolution emerges as an exceptional approach for generating precisely this type of data. Drawing on empirical evidence, I will show that temporal phenotypic data enable the identification of adaptive patterns, even when the selected trait(s) are unidentified, as is often the case in natural and experimental populations. Finally, I will discuss the next generation of evolution experiments, designed to mimic th...

The interplay between natural selection and migration is predicted to shape the architecture of adaptation in different ways, depending on whether the direction of selection is spatially homogenous or heterogeneous. When different populations experience selection towards a similar phenotypic optimum, there is no tension with migration and "global adaptation" proceeds in manner similar to that predicted for a single population. By contrast, when populations are selected towards different optima, "local adaptation" occurs, which tends to favour architectures driven by fewer, larger, and more tightly clustered alleles than global adaptation. Despite this clear theoretical prediction, there have been few, if any, comprehensive tests in natural populations. Here, we bring together genome sequence data from thousands of individuals from 25 species of plants to compare signatures of repeated selective sweeps (global adaptation) with those of genotype-environment association (local adaptation)...

Presented as part of the SciComm Collider 2 workshop.
All PI Residents are invited. 

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A colloquium featuring 2 perspectives on science communication.

Tatiana Erukhimova - Making Physics Fun and Approachable
Matthew Strassler - The Challenge of Communicating Physics Accessibly, Clearly and Accurately

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The correlation functions of large-scale fluctuations are crucial observables in modern cosmology. These boundary correlators contain rich information about the bulk dynamics and can be used to probe physics at the inflation scale. There have been considerable efforts in the analytical study of inflation correlators in recent years. In this talk, I will introduce the basic structure of inflation correlators and several analytical methods we have developed for their computation. In particular, I will introduce the method of partial Mellin-Barnes (PMB) representation. With this method, we can largely solve the massive tree correlators analytically. At the loop level, we use PMB to prove a factorization theorem for the nonanalytical part of inflation correlators, which produces a characteristic nonlocal signal. Finally, we can recover the full correlator starting from this nonanalytical part using a dispersion integral.

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