Archive by category | Evolution

Tara Oceans back home

Tara Oceans back home

The Tara Oceans expedition (oceans.taraexpeditions.org) just arrived last Saturday in Lorient, France, after sailing across the seas of the planet for more than 2 years, collecting samples of planktonic life and recording physical, geographical and climatic parameters in a systematical manner over a total of 153 stations.  Read more

[Research highlight] Cis-regulatory evolution, not so mysterious after all?

Animal genomes are littered with conserved non-coding elements (CNEs)—most of which represent evolutionarily constrained cis-regulatory sequences—however, it is often not clear why these sequences are so exceptionally conserved, since anecdotal examples have shown that orthologous CNEs can have divergent functions in vivo (Strähle and Rastegar 2008; Elgar and Vavouri 2008). In an article recently published in Molecular Biology & Evolution, Ritter et al. compare the functional activities of 41 pairs of orthologous conserved non-coding elements (CNEs) from humans and zebrafish (2010). Interestingly, sequence similarity was found to be a poor predictor of which CNEs had conserved function. In contrast, the authors found that measuring transcription factor binding site change, instead of simple sequence divergence, improves their ability to predict functional conservation.  Read more

The role of neutral mutations in the evolution of phenotypes

The role of neutral mutations in the evolution of phenotypes

Research highlight by Pedro Beltrao, University of California, San Francisco In a recent opinion piece, Andreas Wagner tries to reconcile the tension between proponents of neutral evolution and selectionism (Wagner 2008). He argues that “neutral mutations prepare the ground for later evolutionary innovation”. Wagner illustrates this point using a network model of genotype-phenotype relationships (Wagner 2005). In a so-called ‘neutral network’, nodes correspond to distinct genotypes associated with the same phenotype and are connected by an edge if the respective genotypes differ only by a single mutation event (eg point mutation). Examples of neutral networks include different genotypes coding for  … Read more

Rewiring E. coli transcriptional network

Rewiring E. coli transcriptional network

Research highlight by Kazuharu Arakawa and Masaru Tomita, Institute for Advanced Biosciences, Keio University, Japan Gene duplications and mutations are central driving forces in the evolution of genomes. Genomes must be robust to such changes in order to be evolvable, and many studies have probed genome robustness using systematic gene knockouts or overexpression experiments. In a recent paper, Isalan et al. (2008) took a new approach to test the robustness of Escherichia coli gene circuitry by reconstructing gene duplication events by shuffling the promoter-ORF pairs for about 300 transcription factors and introducing 598 recombined pairs one-by-one into E. coli to  … Read more