Friday, February 22, 2013

Identical mutations in separate populations

Or similar changes in the environment favor similar (and some times identical) mutations.
  1. Grow E. coli in medium with glucose and acetate.
  2. See how specialized populations emerge.
  3. Sequence.
  4. Observe parallel emergent changes in independent populations.
Herron, M. D. & Doebeli, M. 

Parallel Evolutionary Dynamics of Adaptive Diversification inEscherichia coli

PLoS Biol. 11, e1001490 (2013).

Wednesday, February 20, 2013

Un articulito de la falibilidad de googleflu, manifiesta la temporada 2012-13:

http://www.nature.com/news/when-google-got-flu-wrong-1.12413

menciona también los sistemas de monitoreo por reporte directo de síntomas -aunque parecen creer que empezaron hace dos años en Francia (¡!).

Tuesday, February 19, 2013

No need to see all


Or how to determine what elements of the network are good sensors.


Inference diagram is constructed by drawing a directed link (xi → xj). SCCs, which are the largest subgraphs chosen such that there is a directed path from each node to every other node in the subgraph, are marked with dashed circle; root SCCs, which have no incoming links, are shaded in gray. A potential minimum set of sensor nodes, whose measurements allow us to reconstruct the state of
all other variables is shown in red.

Yang-Yu Liu, Jean-Jacques Slotine, and Albert-László Barabási
Observability of complex systems
PNAS | February 12, 2013 | vol. 110 2460–2465

Sinónimos mis polainas


El sesgo en el uso de codónes es un hecho. También lo es el correspondiente sesgo en la producción de tRNA's. En este artículo, se muestra como tal sesgo en tRNA's puede afectar la velocidad de transcripción, lo que, tratándose de una enzima clave, puede a su vez decrecer el fitnes de Methylobacterium extorquens.

En breve, las mutaciones sinónimas no son tan sinónimas, si se trata de genes clave.

Deepa Agashe, N. Cecilia Martinez-Gomez, D. Allan Drummond, and Christopher J. Marx
Good Codons, Bad Transcript: Large Reductions in Gene Expression and Fitness Arising from Synonymous Mutations in a Key Enzyme
Mol Biol Evol (2013) 30(3): 549-560 first published online December 4, 2012 doi:10.1093/molbev/mss273

PDF aquí