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Add to Calendar 3/9/2018 2:00 pm 3/9/2018 America/Chicago Special Seminar: "A multi-scale view of the dynamics and predictability of laboratory evolution" DESCRIPTION:

Large, rapidly adapting microbial populations have remarkably rich evolutionary dynamics. A multitude of beneficial mutations occur simultaneously and compete in the population, the majority never rising to substantial frequencies. Yet the fates of those that do depend crucially on the benefits of the future mutations that arise in the population. However, the observation and monitoring of these dynamics has been challenging: traditional metagenomic sequencing methods allow us to observe only mutations that reach relatively high frequencies (> 1%), whereas newer barcoding approaches are limited to the earliest phases of adaptation, before the first beneficial mutations rise to high frequencies. We have developed a new high-efficiency genomic re-barcoding technique that enables us to repeatedly introduce high- diversity DNA barcodes into yeast laboratory populations over the course of evolution. By sequencing the barcode locus over time, we can track the frequency of lineages founded by unique barcodes and their descendants, as they change due to drift and selection, and diversify through new mutations. The data reveal a remarkable Russian-doll-like pattern in the evolutionary dynamics, characterized by nested clonal interference events. Using a theoretical insights, we can infer the fitnesses of individual lineage and analyze how the distribution of fitness within the population arises from clonality and changes over time, and to quantify how competition between high-fitness lineages determines the limits of predictability.

\n\nSPEAKER:

Ivana Cvijovic, Harvard University

2004 NHB

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Special Seminar: "A multi-scale view of the dynamics and predictability of laboratory evolution"

Speaker Ivana Cvijovic, Harvard University
Date: 3/9/2018
Time: 2 p.m.
Location:

2004 NHB

Event Contact: James O'Dwyer
jodwyer@illinois.edu
Sponsor:

School of Integrative Biology

Event Type: Seminar/Symposium
 

Large, rapidly adapting microbial populations have remarkably rich evolutionary dynamics. A multitude of beneficial mutations occur simultaneously and compete in the population, the majority never rising to substantial frequencies. Yet the fates of those that do depend crucially on the benefits of the future mutations that arise in the population. However, the observation and monitoring of these dynamics has been challenging: traditional metagenomic sequencing methods allow us to observe only mutations that reach relatively high frequencies (> 1%), whereas newer barcoding approaches are limited to the earliest phases of adaptation, before the first beneficial mutations rise to high frequencies. We have developed a new high-efficiency genomic re-barcoding technique that enables us to repeatedly introduce high- diversity DNA barcodes into yeast laboratory populations over the course of evolution. By sequencing the barcode locus over time, we can track the frequency of lineages founded by unique barcodes and their descendants, as they change due to drift and selection, and diversify through new mutations. The data reveal a remarkable Russian-doll-like pattern in the evolutionary dynamics, characterized by nested clonal interference events. Using a theoretical insights, we can infer the fitnesses of individual lineage and analyze how the distribution of fitness within the population arises from clonality and changes over time, and to quantify how competition between high-fitness lineages determines the limits of predictability.

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