Adaptation Lab

Welcome to Deepa Agashe’s lab at the National Centre for Biological Sciences (NCBS), Bangalore!

Organisms often face new, changing or otherwise challenging environments, which can drive evolutionary adaptations. However, different populations and species often respond differentially to the same environmental change, potentially altering their evolutionary trajectories. For instance, some organisms flourish in new environments, whereas others go extinct. What factors determine individual and population-level responses, and what are the processes and molecular mechanisms that mediate adaptation to new habitats? We are motivated by these broad questions at the forefront of research in ecology and evolutionary biology.

New paper: Mistranslation can be good!

Our work on ‘useful’ mistakes in bacteria (E. coli) is finally out! Laasya and Parth found that making rebel proteins not encoded by our DNA can be a good thing. In cells that frequently make mistakes, the accumulated ‘junk’ proteins end up triggering a high alert situation. This allows the cells to better deal with various external assaults (like increased temperature, damage to DNA and so on). When everything is normal this isn’t a big deal; in fact the junk makes cells mildly sick.  Under stress though, the high alert and error prone cells get the upper hand, leaving behind the more accurate (but less prepared) regular cells. For more: read the paper, and an NCBS news article. And, enjoy this summary cartoon from Pranjal Gupta!

Striking image with explanation

New paper: Methylobacterium distribution shaped by host rice

Bacteria are so small and so ubiquitous that it seems like they should be found everywhere. But recent work shows that much like animals and plants, most bacteria have discrete distributions. We asked: does host association shape bacterial distribution in nature? In Pratibha’s first paper from the lab, we describe how bacteria from the genus Methylobacterium are distributed across nearly 40 different rice landraces from Arunachal Pradesh and Manipur. Collaborating with the labs of Shivaprasad and Radhika at NCBS, we found that bacterial carbon-use phenotypes are largely shaped by the landrace they inhabit. Suprisingly, sugar availability on rice leaves does not correlate with the carbon-use phenotypes, leaving us with many new questions. For more, read the paper. Meanwhile, enjoy this lovely illustration by Pranjal Gupta!


New paper: Butterflies don’t need bacteria for survival and development

Kruttika’s work testing the impact of butterfly caterpillar microbiomes on growth and survival is published! This was a major collaborative effort with Krushnamegh Kunte, and very new kind of work for our lab. The results were puzzling because unlike patterns from other insects, butterflies seem to be just fine without their bacteria. But in conjunction with Rittik and Ashwin’s recent results with dragonflies, it seems that we’ve uncovered one end of the spectrum of host-microbe interactions. The end that spells “meh!” rather than “I need you”. Here’s a cartoon summary of the work by Kruttika and Shreya. Also read a lay summary here; or read the paper for more details!


New paper: The little inhabitants of mighty dragon(flies)

Rittik Deb and Ashwin Nair’s paper on the gut bacterial communities of dragonflies is out! We sampled several species of dragonflies from different locations in India, and found that gut bacterial communities varied across host species, location, and season. For some of the dragonflies, we were also able to analyse gut contents, and found that these “generalist predators” eat quite different meals that probably end up introducing distinct bacteria in their guts. So, unlike in most other insects, dragonfly gut bacterial communities seem to be transient and are neutrally assembled (rather than host-selected). Read the paper for more details. Meanwhile, enjoy this beautiful summary of the paper by Pranjal Gupta!


Announcing the 2020 ICTS School on Population Genetics and Evolution

PopGen2020Kavita Jain and I are pleased to announce the fourth edition of the Bangalore School on Population genetics and Evolution. As always, we have an exciting speaker lineup, and we look forward to a group of enthusiastic participants. We invite applications from PhD students and postdocs (and exceptional MSc students) from biology, computer science, physics, or mathematics backgrounds. The key requirement is a strong interest in population genetics and/or evolutionary biology. Applications close 1 Oct 2019. For more information, see the school website.

2019 Conference season is upon us!

We are off to various conferences this year. Come listen to our talks, visit our posters, and talk science!

Aparna is already at Evolution 2019, to talk about the role of microbiomes during host adaptation in the Hamilton Award Symposium. We are rather proud that Aparna was selected to present as a finalist! She will also present a poster, and speak at the Story Collider event, Outside the Distribution. Do go talk to her!

In early July I will be at the Gordon Research Conference for Microbial Population Biology at Andover, NH, USA, presenting a poster on our beetle microbiome work. I’m super excited about this meeting, which is a great collection of microbially inclined folks.

Around the same time, Laasya will present a poster on her mistranslation work, at the EMBO|EMBL symposium on New approaches and concepts in microbiology in Heidelberg, Germany.

At the end of July, Parth and I will head to SMBE 2019 in Manchester, UK, presenting posters on the evolution and importance of translation and mistranslation, respectively. I am also organizing a symposium on the Causes of Parallel Molecular Evolution with Alex Couce. Come visit our posters, and listen to the amazing speakers in our symposium!

In August, Vrinda will be in Turku, Finland, speaking at ESEB 2019 about the population dynamics of laboratory-evolved beetles in new habitats. She has really fun data, so do check out her talk!

And finally, in the last week of August Laasya will present a poster and a talk at the FEMS summer school for postdocs: Bacterial robustness and mechanisms of death, in Split, Croatia.

New paper: Explaining population level variation in immune priming

Graphical Abstract_finalHere’s the latest from Imroze and Arun. A couple years ago we had found surprising levels of variability in immune memory (“priming”), across 10 wild-collected flour beetle populations (Khan et al 2016, Ecology and Evolution). In our new follow-up paper, we figured out what may explain this variation, by systematically analysing change in various fitness components in the populations, after priming. In a nutshell, it appears that priming is beneficial both for reproduction and for survival; but the relative benefits of priming may trade off. So, priming is stronger in beetle populations that are more susceptible to the pathogen; but it is weaker in populations that have a larger investment in fecundity after priming. Read the paper to find out more!

Pratibha’s interview on Doordarshan

Listen to Pratibha discuss chemical ecology and her work on the Methylobacterium species associated with traditionally cultivated rice varieties here! The talk (in Manipuri) was aimed at the farmers in Manipur. Pratibha is currently testing whether Methylobacterium spp. isolated from rice are beneficial to the host plant, and hopes that this project is ultimately useful for agriculture and to preserve the traditional rice landraces in the North-east.