Adaptation Lab

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

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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.

New paper: Antagonistic pleiotropy is rare!

Mrudula and Joshua’s paper measuring the incidence and fitness effects of antagonistically pleiotropic mutations is now out in Evolution!

As they improve at performing one function, organisms often get worse at another function. Such a negative relationship between two functions (or traits) is called a tradeoff, and is a central idea in evolutionary biology. Tradeoffs may constrain adaptation, and underlie many important evolutionary processes such as the evolution of organisms’ life history strategies, diversification and speciation. One way in which tradeoffs can arise is via mutations that are antagonistically pleiotropic. These mutations increase fitness in one environment, while simultaneously decreasing fitness in another. Antagonistic pleiotropy (AP) could therefore explain tradeoffs if such mutations were frequent and had large fitness effects. However, the frequency and fitness effects of these mutations remains poorly studied.

Runners_tradeoffs

 

We measured the frequency and fitness effects of AP mutations across 11 different carbon sources in a large set of random single mutations in Escherichia coli. Our results suggest that overall AP is very rare, and that AP-mediated tradeoffs are unlikely to constrain adaptation very often. Thus, while there is no denying that tradeoffs are abundant in nature, it is unlikely that they are caused by single antagonistically pleiotropic mutations. Rather, accumulation of multiple mutations in genes that are not under very strong selection may degrade other functions, presenting as a tradeoff.

For more details, browse the paper or the associated NCBS news article.