The
Chavhan
Lab for
Understanding
Evolution
Research themes
The evolution of multicellularity
Studying the evolution of multicellularity is crucial for discerning how biological complexity evolves. We focus on the origin and evolution of the capacity to form undifferentiated cellular clusters, which was likely the first key step towards the evolution of multicellularity. To study how and why multicellularity evolves, we try to recreate this evolutionary transition in the lab using a variety of bacterial model systems. To know more, please read our foundational paper in this context.
Phenotypic plasticity can facilitate in the evolution of multicellularity
Phenotypic plasticity enables a single genotype to exhibit contrasting phenotypes in different environments. We have recently shown that such plasticity can also help bacteria in evolving macroscopic multicellularity.
Such plastic phenotypes can act as leaders while genes act as the followers duringn the evolution of multicellularity:
Escherichia coli (wild type ancestor)
Using experimental evolution, we evolved bacteria that are obligately (constitutively) multicellular:
The macroscopic multicellularity of our experimentally evolved bacteria makes them ideal model systems to conduct pioneering experiments to evolve cell differentiation de novo in the laboratory (this is going to be a major focal area in our lab):
We also want to experimentally test if cell differentiation can evolve in response to some specific kinds of predation:
We are also actively investigating several other questions (what we end up studying is shaped not only by what Yash (the PI) is interested in, but also on what the PhD students in our lab like). Some of these questions are listed below:
1. Can phenotypic plasticity facilitate the coexistence of antagonistic species?
(Manuscript under preparation. This project was driven jointly by Diya and Hadi.)
2. Can geometric asymmetries in selection lead to the origin of new cell types?
(Write to us if you want to know more: we can show you some nice images of our evolved phenotypes! This project is spearheaded by Hadi.)
3. Are there ecological and developmental thresholds that put a lower limit on the size of a fully multicellular individual? How does geometry shape such thresholds?
(The answer is a big YES!. We have discovered dual thresholds that limit how small a multicellular individual (capable of a full life cycle punctuated by unicellular propagules) can be. If you want to know the math, contact us! This project is driven by Pratyay.)
4. What determines the evolution of generalists or specialists when it comes to bacteria-bacteriophage coevolution?
(We address this question using experimental coevolution with several phage-host pairs. This project is spearheaded by Anuraag.)
5. How does evolution fix a leaky bacterial cell?
(Our system allows us to address such a simple question in a highly multifaceted manner using a large number of different phenotypic perspectives. This project is driven by Vignesh.)
6. How do fluctuations in the intensities of demographic bottleneck shape asexual adaptation?
(If you are interested in the mathematics of adaptation, we have intriguing experimental results that can challenge the current theoretical state of the art. Write to us if you would like to join us as a mathematician to better understand how asexual adaptation works! This project is driven by Jyoti.)
