Monday, January 30, 2006

Adenovirus and obesity?

This may be a bit of a stretch but researchers have found that in 3T3-L1 cells in vitro, Ad-31, Ad-36, and Ad-37, but not Ad-2, increased adipocyte differentiation and triglycerides accumulation. Maybe H5N1 also causes obesity, this would explain the correlation between fat people and KFC.


Viruses Don't Kill People; Human Behaviour Kills People

Here's my contribution to the killer flu debate: I call it the Law of Virulence. There's a good chance it's overly simple and probably not original. But it sill makes a point.

Simply saying that the virulence of a pathogen within the population goes up when population density goes up, down when resistance goes up. By population resistance I refer to a combination of factors such as pre-existing immunity (ie through vaccination), innate immune status, general health and nutrition level, hygeine habits (ie frequency of handwashing), food preparation habits, agricultural practices, etc. etc. It is the inverse of susceptibility.

This law is built on the fact variants with a capcity for lethality have always existed within the various quaspecies of pathogens continuously circulating within human and animal populations.
However, since infectious spread is severly compromised by high virulence, such strains can take hold when infectivity is saturated in extremely densely populated groups with high susceptibility. Thus the emergent "killer strains" everyone talks about in the news are not some new creation from thin air, but normally latent strains whose prevalence is increased by changes in human behaviour that increase population density and/or decrease resistance. Unfortunately these two factors are often coupled. For example poverty which decreases resistance through its effects on nutrition and health, tends to be prevalent in overly populated cities.

So don't be afraid of H5N1 or any other pestilence that might be cast down upon our poor helpless souls by the Almighty. Instead, fear the dark side of irresponsible civilizations: poverty, malnutrition, inadequate health care and lack of education within our massive, rapidly growing, and highly interactive global population.


Earl Brown on the Flu Scare

"What can be more intimate than having your hand up to the wrist in the rear end of an infected chicken that is being prepared for dinner?"
U of O's resident influenza expert Earl Brown weighs in with some cutting scientific insight on the H5N1 scare in the latest BMI bulletin.


Friday, January 27, 2006

On heritable behaviour

Not to be outdone by Tony, I also post a picture

I think Tony brought up an interresting point, wich is worth a post rather than just a comment. I think the fact that behaviour can be inherited is undisputed. Some call these intincts, but basically, any kind of gene that can influence the chemical makeup of the brain or neuronal connections that statistically favours a particular behaviour which increases reproductive sucess will be evolutionarily stable. Now something as complex as behaviour is definately multigenic and so drastic changes in behaviour will require a more flexible system then something that solely relies on genes. The advantage of a flexible system, is that any kind of new situation, never encountered before in nature can elicit an appropriate behaviour which can even be passed on by teaching. Even blocking the irrational behaviour of a primate on a GT with suicidal tendencies. Does one need mirror neuron to learn? Not necessarily, ants are able to couple in a teacher/pupil pair to teach with both positive and negative reinforcements where food is and how to collect it. Is new behaviour heritable? There is a possibility that through imprinting one could potentially pass on new epigenetic changes affecting behaviour to its offspring. Evolutionarily speaking, this does not seem to be a stable strategy. Such a change may or may not be beneficial, and it can easily be erased in the next generation. There is however another way it can be passed on. According to Dawkins, brains are replicating machines, and ideas can be replicator. These self replicating ideas are called memes. In an objective point of view, the only "purpose" of a meme is to replicate, and to do so it must "infect" a brain. If a meme is good at being passed around it will remain stable in the memepool and be part of the culture. The meme does not need to be beneficial to the individual per say, since the individual does not need to survive or reproduce for the meme to replicate. It needs only to be catchy. For example the meme of religion is a particularly successfull one. It is debatable wether this meme is beneficial to the individual harbouring this mind virus. Yet it is good at getting passed on. It has very sucessfull co-infectors that complement it, such as the promise of life after death, or the fear of hell. The point is that behaviours can easily be horizontally heritable, but one must think outside of genes and reproduction to fully understand how they can be passed on...


Thursday, January 26, 2006

Pondering Heritable Behaviours on my GT Snow-Racer...Immaculate Conception Through Teaching?

So this past weekend at the Super-Fun Snow Jam of the Century, sitting on a GT snow-racer at the top of a cliff, working up the courage (ie insanity) to plummet down onto the ramp projecting over the ravine below, my thoughts inevitably turn to evolutionary biology. At first, I mostly ignored the whimpering and frantic looks from Mannie the German Shepherd, who was directly blocking my path, and tried to kick her out of the way. However, as I now know, German Shepherds are BIG and HEAVY and this one was determined I was not going down that hill. Then it dawned on me - this dog was herding me. I guess from a shepherd's point of view, her behaviour made sense. I was big and stupid enough to choose to rocket down to my own demise, but no idiot would want their sheep sent over a cliff, off a snow jump and into a ravine filled with running water.

Now here's what gets me. This dog has never seen a sheep in its life. Since it was probably cruelly ripped from its mother's bosom in infancy, neither did it ever have the chance to learn herding behaviours from its parents. Yet it does a great job trying to shepherd everything in site. A born shepherd. No doubt her offspring (if she still had reproductive capacity) would be the same. Heritable behaviour. Just like Rob's pointer hunting dogs.

That seems interesting to me, but maybe its not news to anyone else. At any rate, what seems even more intriguing to me is that not only are behaviours/skills heritable from one generation to the next, but they can be taught and learned between individuals (even unrelated individuals). As V.S. Ramachandran points out in the doco Rob posted, this ability is an obvious evolutionary advantage in terms of speeding up adaptation to environmental challenges. He suggests the capacity to learn is unique to humans and could be a function of mirror neurons. I tend to disagree; although humans might be the most prolific learners/teachers, you can clearly teach a dog tricks.

At any rate all this seems to suggest to me that behaviours learned by an individual after birth could be programmed into the genetic makeup of germ line cells and thus passed on to offspring. Thus, a university professor or celibate priest, by teaching or preaching ideas could reproduce their genes without ever gettin' it on so to speak. This doesn't seem to fit with current biological theory as I understand it, so can someone please explain to me why I'm wrong?


Saturday, January 21, 2006

Mirror Neurons

Some rather Anonymous Coward mentioned mirror neurons at coffee club as being a possible source for predictive even 'extrasensory' perception. Even if there is no way they are doing anything of the sort they certainly are interesting:
An article on mirror neurons by a very influential neuroscientist, V.S. Ramachandran.
A short and simple PBS doco on mirror neurons.
Mirror Neuron talk is also included in the Emerging Mind lectures 2003 from the BBC (also with V.S. Ramachandran) and I thought these lectures were an excellent listen.


Friday, January 20, 2006

Virus complementation & disease

Some of us use virus complementation by tumour cell as an approach to treat cancer. But this paper in science suggest that different dengue virus serotypes can complement each other... The introduction of defective virus that need coinfection to spread could be useful if they are stable enough to propagate efficiently in the population. Could we use them as a tool (in mosquitoes, not humans)? If we make a virus that replicates faster because it lacks capsid components, can it overtake a population and eventually make it crash when it reaches a certain treshold. Kinda like fighting fire with fire...


Science now on the podcast bandwagon

About time...


Wednesday, January 18, 2006

Trivia Night

Don't forget about trivia night, Monday Jan 30th, at 7pm...


Should induction be part of the scientific method?

There are a lot of differing opinions about what the scientific method is or should be. It seems straigthforward: take some empirical evidence, use Karl Popper's falsifiable hypotheses scheme, do the experiment and repeat. Yet some people have a beef with the first part. In maths you can start with axioms, wich exist in plato's mathematical world and do not need to exist in our "real" world to be true. In biology we do not have this convenience. Is it ok then to start with observations rather than only deductions? When it comes to philosophy, age brings wisdom, and in honnor of Irving Rothchild, a famous reproductive biologist who just kicked the bucket at 92, I bring you his latest paper "Induction, Deduction, and the Scientific Method: An Eclectic Overview of the Practice of Science" which he published just earlier this month. I dunno about you but if i can think this clearly at 92 I'll be pretty happy!


Monday, January 16, 2006

Read this before you panic! On emerging infectious disease...

Just thought I'd share this well-written and insightful article on emering infectious disease appearing in the Royal Society's journal. Check it out...a rational alternative to all the fear-mongering going on in the media these days. Like any good read, it has lots of history and even some pretty funny parts.

(Fixed link for real)


Friday, January 13, 2006

Friday funnies

If you need to kill time on fridays, lets say hypothetically before a committee meeting for example, I recommend these two sites: Penny arcade, which pokes fun at D&D and video game nerds, I'm not thinking of anyone in particular, or Something Awful with their great photoshop phriday.


Tuesday, January 10, 2006

#1 paper on PLOS biology

This new paper entitled "Ancient and Recent Positive Selection Transformed Opioid cis-Regulation in Humans" posits that humans have had positive selection of promoters of opoid genes to be more inducible. Definately worth the read.


Monday, January 09, 2006

IA Updates...I Recommend Letterman vs. O'Reilly

Amongst the latest IA updates I found a link to this great clip of David Letterman and conservative media-guy Bill O'Reilly going head to head. If you haven't seen them, clips of Jon Stewart's recent Crossfire appearance, Frank Zappa's 1980's Crossfire appearance (this is a must-watch!), Kayne West's impromtu attack on George W. during a Katrina relief program and Will Ferrell's Bush on the Ranch spoof ad are all priceless.


Friday, January 06, 2006

Listen to a genius

The latest episode of Nerd TV was pretty aweseome. Doug Engelbart, the dude who envisioned the mouse in the podcast.