Archive by category | Computational_approaches

[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

Keystone Symposium – Omics Meets Cell Biology (II)

Keystone Symposium – Omics Meets Cell Biology (II)

Before I carry on with a summary of the second part of the Keystone Symposium ‘Omics Meets Cell Biology’, I should clarify that this post and the previous one dedicated to this conference are not intended to provide an comprehensive account of all the talks but rather to communicate some general (and subjective) impressions of the meeting. To keep these posts reasonably short (and sometimes due to a lack of memory…), I had to omit several of the excellent presentations given at this meeting. The full program and complete list of speakers is available at the Keystone Symposium website.  Read more

Keystone Symposium – Omics Meets Cell Biology (I)

Keystone Symposium – Omics Meets Cell Biology (I)

At the Keystone Symposium ‘OMICS Meets Cell Biology’, held this week in Breckenridge, Colorado, attendees had initially to face two major challenges: the first was to survive the cocktail mixing jet lag and altitude sickness and the second one—oh, it hurts!— was to resist the temptation to just forget all about science and focus exclusively on the concepts revolving around snow, slopes and fun sports…  … Read more

The role of neutral mutations in the evolution of phenotypes

The role of neutral mutations in the evolution of phenotypes

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 RNA or protein structures. In this representation, highly connected networks correspond to robust phenotypes that are not very sensitive to changes in genotype. Wagner notes the zinc finger fold as an impressive example of a highly connected neutral network as its structure remains essentially the same even after mutating all but seven of its 26 residues to alanine.  Read more

SciFoo: scientific fireworks

SciFoo: scientific fireworks

In his list of eight ‘generative’ values (Better Than Free), Kevin Kelly includes ’embodiment’–the actual physical realization of an item or event which could be otherwise freely distributed over the web. While we are all ‘hyperlinked’ on the Internet, the value of those unique qualities that cannot be generated or “copied” on the web is dramatically increased. The type of intense emulation and shared excitement sparked at the recent Science Foo Camp (SciFoo 2008), organized by Nature, Google and O’Reilly, gave a wonderful example of the unique value of direct human exchange during an exclusive event bringing together roughly 200 top scientists, ‘geeks’ and other technologists at the Googleplex in Mountain View, California.  Read more

ISMB 2008: micro-blogging at its best

Probably like many others, I have often been puzzled by the phenomenon of ‘micro-blogging’, which consists in posting very short messages on the web (typically via sites such as Twitter) with the goal of providing an instantaneous description of the activity, state of mind or thoughts of the writer. The last few days, a small group of bloggers attending the ISMB 2008 Conference in Toronto used a form of collective micro-blogging on FriendFeed in an intensive way to cover many of the talks held at the conference.  Read more

Fascinating correlations or elegant theories?

Chris Anderson, Editor-in-Chief of Wired , wrote a few weeks ago a provocative piece “”http://www.wired.com/science/discoveries/magazine/16-07/pb_theory”>The End of Theory: The Data Deluge Makes the Scientific Method Obsolete“, arguing that in our Google-driven data-rich era (”The Petabyte Age”) the good old “approach to science —hypothesize, model, test — is becoming obsolete”, leaving place to a purely correlative vision of the world. There is a good dose of provocation in the essay and it was quite successful in spurring a flurry of skeptical reactions in the blogosphere, FriendFeed-land and lately in Edge’s Reality Club.  Read more

A refreshing model: peppermint terpenoids

A refreshing model: peppermint terpenoids

Living cells are typically asymmetric, having tens of thousands different biopolymers (proteins and polynucleotides), but merely <1000 types of small molecules, such as amino acids and lipids. An exception is certain plant cells that harbor members of ~40,000 strong group of low molecular weight terpenoids, often displaying a complex compositional balance essential for plant growth and survival (Aharoni et al, 2005). Understanding the intricacies of biosynthesis and interconversion of such unusual cellular components appears to require the full power of Systems Biology. In a recent paper, Rios-Estepa et al (2008) harness a systems approach, including iterative cycles of mathematical modeling and experimental testing, to help elucidate the metabolic dynamics of the terpenoid universe.  Read more