What we’re reading: Hyper-mutating symbionts, cichlid genomes, and active learning in biology class

A compulsive reader

In the journals

Remigi P, D Capela, C Clerissi, L Tasse, R Torchet, et al. 2014, Transient hypermutagenesis accelerates the evolution of legume endosymbionts following horizontal gene transfer. PLoS Biology. 12(9): e1001942. doi: 10.1371/journal.pbio.1001942.

Following introduction of the symbiotic plasmid of Cupriavidus taiwanensis, the Mimosa symbiont, into pathogenic Ralstonia solanacearum we challenged transconjugants to become Mimosa symbionts through serial plant-bacteria co-cultures. We demonstrate that a mutagenesis imuABC cassette encoded on the C. taiwanensis symbiotic plasmid triggered a transient hypermutability stage in R. solanacearum transconjugants that occurred before the cells entered the plant.

Brawand D, CE Wagner, YI Li, M Malinsky, I Keller, et al. 2014. The genomic substrate for adaptive radiation in African cichlid fish. Nature doi: 10.1038/nature13726.

We found an excess of gene duplications in the East African lineage compared to tilapia and other teleosts, an abundance of non-coding element divergence, accelerated coding sequence evolution, expression divergence associated with transposable element insertions, and regulation by novel microRNAs. In addition, we analysed sequence data from sixty individuals representing six closely related species from Lake Victoria, and show genome-wide diversifying selection on coding and regulatory variants, some of which were recruited from ancient polymorphisms.

In the news

“My big challenge in creating an active-learning lesson is not to decide what to teach but what to not teach.”

“If you have a tendency, like many overwhelmed individuals, to tell yourself that that you’ll get your important work done later — maybe at night or on the weekend — you increase your chance of procrastination during the day.”

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About Jeremy Yoder

Jeremy Yoder is an Assistant Professor of Biology at California State University, Northridge. He also blogs at Denim and Tweed, and tweets under the handle @jbyoder.
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