Cornejo Lab

School of Biological Sciences, WSU

Paul Allen School of Biological


08/19/2013  Our study looking at the role of natural selection shaping the genetic diversity in Natural populations of Mycobacterium tuberculosis is out in PLoS Pathogens. Go Caitlin (Pepperell Lab)!

08/16/2013  I have joined the faculty of the School of Biological Sciences at Washington State University (Pullman, WA). Interested students: contact me!

07/19/2013  The cacao genome and an example of its use to map complex traits like pod color is out in Genome Biology!

The Palouse, our new home (photo: OC, 2013)


The increased availability of next generation sequencing has opened an incredible opportunity to ask questions about the demographic history and the genetic basis of adaptive evolution in microbes like Plasmodium and Streptococcus; two groups of organisms we work on. Some of the questions addressed in our lab are: i) Can we infer from retrospective genomic analyses the demographic history of (micro)organisms adn identify candidate genes that might be involved in their adaptation to the current niche (either host or environment)? In the case of pathogenic organisms, these questions are interesting not only from a population genetic perspective but also have a strong link with health-related problems and how to design public health policies that are consistent with the ecology and evolution or the organisms. ii) What ecological and evolutionary scenarios can explain the maintenance of toxic agents that kill the organisms that produce them? It is a fascinating question that can be addressed with a combination of simple mathematical modeling, experimentation and molecular techniques and can lead to the discovery of new anti-bacterial agents. iii) What are the genetic bases of disease susceptibility? Disease is the output of the interaction of 2 organisms, and as such there are differences in the host population and the pathogen population that potentially affects the variation in clinical outcomes, we are interested in understanding the genetic basis of susceptibility to infections. iv) What are the genetic basis of phenotypic variation in complex traits like disease susceptibility or the ability to produce offspring are questions that present common challenges in organisms with very distinct genomic architectures like Theobroma cacao (chocolate plants) or humans.

  Recently, I have developed a growing interest in the research of population genomics of cacao plants (Theobroma cacao), product of a growing collaboration with Juan Carlos Motamayor (MARS-USDA) and Carlos D. Bustamante (Stanford University). Our interest is to employ re-sequencing data from cacao plants to study their demographic history and to identify the genetic basis of phenotypic traits that have been selected during its domestication and/or could be of potential interest for cacao breeders like resistance to diseases. Cacao is an important crop, with an enormous economic impact for the producing countries (that are generally developing economies), and the principal motivation behind this research is the need to develop genomic resources to preserve cacao diversity and ensure a sustainable future for the crop. Also, we would like to develop cacao as a model system for how to map complex traits in long-lived tropical trees where generating multi generational mapping populations is not feasible.


About the Lab

Contact Information

Washington State University

School of Biological Sciences

PO Box 644236

Eastlick Hall 395

Pullman, WA. 99164-4236

e-mail: omar.cornejo(at)

Phone: +1-509-335-0179

Recent Publications

The research of our lab is aimed to understand basic evolutionary processes that shape genetic variation in populations, and contribute to their adaptive evolution. We are particularly interested in the evolution of microorganisms (but not limited to them), and we combine population genetics/genomics analyses, phylogenetics, simple mathematical models and experimental work to address fundamental questions in their ecology and evolution.