Evolutionary Biology

I am a research associate at IISER Pune who is fascinated by the interactions of mutation, drift, and selection in organismal populations. I am particularly captivated by the complexity that underlies the process of adaptation in seemingly simple asexual systems.


In my current research, I use combinations of bacterial experimental evolution, population-wide genomics, and agent-based simulations to study the following:

  • The effects of population size on adaptation and fitness trade-offs

  • The population genetics of divergent character evolution in identical environments

  • Why costs of adaptation, which are a major assumption of theoretical evolutionary models, are rarely detected in experiments.

Peer-reviewed publications

1. Chavhan, Y., Malusare, S. & Dey, S.

Larger bacterial populations evolve heavier fitness trade-offs and undergo greater ecological specialization.

Heredity 124, 726–736 (2020)
Full text      
Companion article

2. Chavhan, Y., Karve, S. & Dey, S.

Adapting in larger numbers can increase the vulnerability of Escherichia coli populations to environmental changes.

Evolution 73, 836–846 (2019)

Full text

​3. Chavhan, Y., Ali, S. I. & Dey, S.

Larger numbers can impede adaptation in asexual populations despite entailing greater genetic variation.

Evolutionary Biology 46, 1–13 (2019)


4. Karve, S., Daniel, S., Chavhan Y., Anand, A., Kharola, S.S.  & Dey, S.

Escherichia coli populations in unpredictably fluctuating environments evolve to face novel stresses through enhanced efflux activity.

Journal of Evolutionary Biology 28, 1131–1143 (2015)


PhD Thesis

The Effects of Population Size on Adaptation and Trade-offs: Insights from Experimental Evolution with Escherichia coli and Individual-based Models

(Defended on September 6, 2019 under the supervision of Prof. Sutirth Dey at IISER Pune)

The May 2020 Heredity Podcast featuring my recent work

00:00 / 17:12

My talk at the Indo-Swiss Meeting on Evolutionary Biology (Dec 2019)

Yashraj Chavhan's talk at the Indo-Swiss meeting on Evolutionary Biology