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La evolución en un tubo se ensayo en tiempo real.

Según informa la revista Nature en portada, se ha conseguido, por primera vez, seguir la pista a mutaciones genéticas específicas, producidas en sólo unas pocas generaciones, que permiten a una bacteria responder a los cambios ambientales. Este trabajo lo firma un equipo internacional encabezado por Hubertus Beaumont, de la Universidad de Leiden (Países Bajos) y en el que participa Paul Rainey de la Universidad Massey (Nueva Zelanda). Diversos estudios han mostrado que las bacterias pueden cambiar su fenotipo (cómo se expresa su carga genética en función del ambiente) en uno y otro sentido para sobrevivir en nuevos ambientes. Así, por ejemplo, muchas bacterias cambian su carga de antígenos cuando invaden un huésped, en un intento de burlar sus defensas. Estos cambios en el fenotipo no siempre tienen éxito, pero aumentan las probabilidades de tenerlo. Es lo que se conoce como cubrir las apuestas. Un ejemplo del mundo vegetal nos puede ayudar a entenderlo: las plantas suelen germinar sus semillas en un determinado momento del año, si están bien adaptadas al entorno este momento suele coincidir con la temporada húmeda; pero, ¿qué hacen algunas plantas de zonas desérticas? Cubrir las apuestas, es decir, no se lo juegan todo a una mano, y germinan sus semillas al azar con lo que aumentan la probabilidad de que en una de esas germinaciones encuentre humedad. Esta estrategia de cubrir las apuestas es muy simple, pero recoge la esencia de la evolución. La selección natural en estos entornos inciertos hace que el organismo desarrolle rasgos protectores. ¿Cómo emerge exactamente esta adaptabilidad fenotípica? Esta es la pregunta a la que dan respuesta Beaumont et ál. Con objeto de observar cómo evoluciona la cubrición de apuestas, los investigadores se centraron en la observación de Pseudomonas fluorescens, una bacteria común con forma de barra [en la imagen en su entorno natural, la raiz de una planta], en un nuevo tipo de ambiente. Es sabido que la bacteria crece bien en el tubo de ensayo cuando éste ha sido convenientemente agitado de manera que el oxígeno circula bien por el cultivo. El nuevo ambiente consistió, en vez de agitar el tubo, algo a lo que la bacteria está bien adaptada, en permitir que la bacteria creciese en tubos sin agitar (pobres en oxígeno).Como era de esperar algunas bacterias se adaptaron al nuevo entorno, formando colonias con una morfología arrugada, en oposición a la habitual lisa. El equipo identificó estos nuevos tipos de colonia en el tubo de ensayo y los transfirieron a nuevos tubos, repitiendo el proceso 15 veces para seleccionar las nuevas variaciones. Finalmente, la bacteria desarrolló la capacidad de cambiar rápidamente su fenotipo entre “arrugado” y “liso” para enfrentarse a distintos ambientes. Un rasgo tan importante para la supervivencia apareció en unas pocas generaciones. ¿Qué había cambiado genéticamente en las bacterias? Los investigadores secuenciaron el genoma de la bacteria evolucionada y localizaron todas las mutaciones que habían surgido y que podrían contribuir a este nuevo rasgo. El equipo terminó identificando 9 mutaciones que diferenciaban a las bacterias que cubrían sus apuestas de sus ancestros. Consiguieron identificar una mutación específica como la responsable de permitir que el fenotipo pudiese cambiar entre distintas morfologías, mientras que las otras mutaciones eran esenciales para el crecimiento del nuevo tipo de bacteria. Estos resultados sugieren que la estrategia de cambio de fenotipo puede evolucionar fácilmente y podría ser una de las soluciones evolutivas más primitivas para la adaptación de la vida a entornos fluctuantes. Referencia: Beaumont, H., Gallie, J., Kost, C., Ferguson, G., & Rainey, P. (2009). Experimental evolution of bet hedging Nature, 462 (7269), 90-93 DOI: 10.1038/nature08504...

Beaumont, H., Gallie, J., Kost, C., Ferguson, G., & Rainey, P. (2009) Experimental evolution of bet hedging. Nature, 462(7269), 90-93. DOI: 10.1038/nature08504  Experimental evolution of bet hedging


See original: Research Blogging - All Topics - Spanish La evolución en un tubo se ensayo en tiempo real.

The rifting of Africa [Eruptions]

Lava flows from the 2005 Mando Hararo eruption in Ethiopia.

Alright, I had been attempting to ignore this story because it was, well, a little uninteresting at first, but it apparently has legs so I will tackle it.

Slashdot has a post proclaiming:
'Volcanic activity may split the African continent in two, creating a new ocean, say experts. This is due to a recent geological crack which has appeared in northeastern Ethiopia.'

OK. Where do I start?

This is based on a recent study published in Geophysical Research Lettersthat found that the recent volcanism in Ethiopia is related to the active rifting up and down the east side of the continental - an area already known as the Ethiopian/East African Rift. The continent is known to be pulling apart, forming the valleys and deep lakes (like Lake Malawi and Victoria) that have active volcanoes like Oldoinyo Lengai in them. This is nothing new, we've known that Africa is splitting apart for decades - and the rifting has been going on for millions of years.

From what I can gather from the study, the real find is that the fissures formed during the 2005 eruptions at Mando Hararo in Ethiopia are actually part of that rifting - i.e., the crack is part of the "crack" that is splitting the continent. This is not to say that the rifting is starting NOW due to the crack - rather that the fissure is a new manifestation of the active rifting between Africa and the Arabian subcontinent. As with most fissures in actively rifting area, magma came up the cracks - always nice to have ready-made conduits - so this process of cracking and erupting is akin to what we might expect at a mid-ocean ridge (except, at this point, on a continent).

So yes, at some point in the future, water from likely the Red Sea (also an actively rifting and growing ocean) will spill into the East African Rift system and create a new "ocean." However, this process has been going on for millions of years and to come out and misconstrue the study by Ayele and others in GRL as saying that the activity in 2005 started the rifting or that the crack is the "start" of a new ocean just shows that the mainstream media (a) doesn't know how to read science beyond what other media are saying about it and (b) how quickly the real findings of a study can be lost in the murk of speculation.

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See original: ScienceBlogs Select The rifting of Africa [Eruptions]

Get a Free Copy of The Immortal Life of Henrietta Lacks (aka HeLa) to Consider for Course Adoption, While Supplies Last [Culture Dish]

Immortal Life of Henrietta Lacks.small.jpgCalling all academics: If you'd like a free advanced copy of my book, The Immortal Life of Henrietta Lacks, to consider it for course adoption, get thee to Random House's academic blog and request a copy quick, while supplies last (which probably won't be long at the rate things are going). See below for more information on the book, and advanced praise. It's a story with wide potential for course adoption in the sciences, bioethics, African-American studies, womens studies, creative writing, journalism, and much more. Added bonus: If you teach the book this spring, you can also get me to come speak at your school/in your classes as part of my book tour.
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See original: ScienceBlogs Select Get a Free Copy of The Immortal Life of Henrietta Lacks (aka HeLa) to Consider for Course Adoption, While Supplies Last [Culture Dish]

oxy

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Thinking You’re in Control Can Lead to an Impulsive Demise

A new study in the journal Psychological Science investigated the dynamics underlying why we repeatedly convince ourselves that we’ve overcome impulsiveness and can stop avoiding our worst temptations. This particular tendency toward self-deception is called restraint bias, and four experiments were conducted under this study to test the hypothesis that it’s rampant in our bias-prone species....

Nordgren, L., van Harreveld, F., & van der Pligt, J. (2009) The Restraint Bias: How the Illusion of Self-Restraint Promotes Impulsive Behavior. Psychological Science. DOI: 10.1111/j.1467-9280.2009.02468.x  The Restraint Bias: How the Illusion of Self-Restraint Promotes Impulsive Behavior


See original: Research Blogging - All Topics - English Thinking You’re in Control Can Lead to an Impulsive Demise

OLPC: The Best ROI for Indian Children

Today I had an interesting talk with Satish Jha of OLPC India. Overall he had an interesting theme - India has the ability to finance OLPC for all 25 million children in India, and it should do this now - for if children are not studying on a screen today, they (and India) will not reach full potential in the future.

Satish Jha of OLPC India

OLPC is affordable to state governments

Education in India is a province of the state governments, not the national one, and Satish has visited many of them to bring the one laptop per child to their attention. Through OLPC, Satish sees this goal as attainable, since he figures they're really looking at $1 per student per week. How? By financing the $220 cost of the XO laptop and the taxes and other costs of $80 over 5 years, which even with India's mortgage interest rate, would be about $1 per week.

State governments are buying OLPC

Just this week, the state of Manipur decided to buy 75,000 XO laptops, but wisely, put down payment for 1,000 and will procure at a pace that can be effectively deployed. In this way, both Satish and the state government can manage implementation. There are three more states, Kerala, Uttar Pradesh, and Himachal, that are also committed to OLPC. Four more are interested and going through the paraphernalia and Satish expects all of them to join once they realize the benefits to their children.

See original: One Laptop Per Child News OLPC: The Best ROI for Indian Children

Secrets of Google's 3-D Mars, Moon

Want to meet a Martian or spark lunar conflict? Two former NASA specialists give tips for making the most of Google's 3-D space offerings—and offer hints for finding some little-known gems.
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Soft-Shell Crabs Created On Demand?

Researchers may have found a way to induce molting in blue crabs, which could increase the availability of soft-shell crabs, considered a delicacy.
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