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Related Experiment Video

Updated: Jun 12, 2026

Determining the Likelihood of Variant Pathogenicity Using Amino Acid-level Signal-to-Noise Analysis of Genetic Variation

Determining the Likelihood of Variant Pathogenicity Using Amino Acid-level Signal-to-Noise Analysis of Genetic Variation

Published on: January 16, 2019

Experimental evidence that source genetic variation drives pathogen emergence.

John J Dennehy¹, Nicholas A Friedenberg, Robert C McBride

¹Biology Department, Queens College and the Graduate Center of the City University of New York, Flushing, NY, USA. john.dennehy@qc.cuny.edu

Proceedings. Biological Sciences

|May 21, 2010

Summary

Pathogen emergence relies on migration from source populations, especially during range expansion. Source genetic variation aids adaptation in new environments, driving successful pathogen establishment.

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Area of Science:

Microbiology
Evolutionary Biology
Ecology

Background:

Pathogen mutation allows host jumping, but successful establishment depends on more than just infectivity.
Migration from a source population can introduce beneficial mutations, aiding adaptation in a new host (sink).
This process is relevant for both novel host shifts and range expansions into less favorable conditions.

Purpose of the Study:

To investigate the factors dictating pathogen emergence success in new habitats.
To compare the speed of sink adaptation during host shifts versus range expansions.
To determine the role of source population genetic variation in pathogen adaptability.

Main Methods:

Evolving bacteriophage populations on novel host bacteria under sink conditions.
Manipulating emergence scenarios to mimic host shift versus range expansion.
Using unevolved founding genotypes as controls for sink adaptation.

Main Results:

Sink adaptation occurred fastest under range expansion conditions.
Controls without source migration showed no adaptation.
Host-shift populations exhibited fitness increases, but immigrants' fitness declined, suggesting source population influence.

Conclusions:

Source populations are crucial for driving adaptive emergence at the edge of a pathogen's range.
Range expansion facilitates faster adaptation due to congruent selection pressures.
Migration from source populations provides essential genetic variation for pathogen emergence.