Friday, September 28, 2007

Altruism in Social Insects

Why do some species, like honeybees, exhibit altruistic behaviour like giving up sex and even their own life for the colony? This week's Science podcast helps cast light on this question. You can listen to it here.

The Podcast addresses the findings in this paper, entitled "Wasp Gene Expression Supports an Evolutionary Link Between Maternal Behavior and Eusociality" by Amy L. Toth et. al.

Below are a few excerpts from the transcript of the podcast.

Interviewee – Amy Toth
We are interested in trying to understand the origins of social behavior in animals. And the reason that is so interesting is because it’s really been a long standing mystery that has intrigued many biologists -- even since Darwin -- because typically you think in evolution any animal’s goal in life is to survive and reproduce, so how do we explain something as extreme as, for example, a honeybee, that stings and loses its life to defend its colony. And so basically the question we are asking is where does this type of unselfish or altruistic behavior come from.

....Interviewer – Robert Frederick
Okay, so what was your hypothesis going into this experiment, then?

Interviewee – Amy Toth
We hypothesized that there would be a similar biological basis underlying maternal behavior and altruistic or worker behavior in a social insect. And so if those two behaviors were related in an evolutionary sense, then you might expect them to have very similar types of underlying biological basis.

....Interviewer – Robert Frederick
So, what kind of overlap was there then between the paper wasp and the honeybee?

Interviewee – Amy Toth
Yeah, that’s a good question. So, we can’t answer that definitively because we handpicked our genes. And so what we would really need to do is pick a random set from wasps and a random set from bees to get an unbiased estimate of what the overlap was. And so what we can say is based on the 32 genes that we did look at -- and we probably picked genes that are more interesting and potentially more likely to show differences -- we saw about 62% of those showed differences in the wasps that were associated with behavior. So, a very high percentage were showing interesting differences in gene activity in the brains of the wasps.

Interviewer – Robert Frederick
Did the expression of these genes backup what had been observed in the wasp as far as how it was different than the honeybee in terms of the rearing behavior of the wasps?

Interviewee – Amy Toth
So, a lot of them did, I would say follow up with an expectation we had. So, as I had mentioned before some of the genes that we chose were associated with foraging behavior in honeybees, and, in fact, a big part of being a worker or being a maternal foundress in these wasp colonies is foraging. And so we actually saw quite a few of the genes that were associated with foraging in honeybees. They also appeared to be turned on or turned off in specific ways in the brains of wasps that were foraging. And this foraging is an essential part of being maternal or being a worker.


Thursday, September 27, 2007

The Sanitary Revolution

Following on from my previous post... I read with interest this BMJ News item on the most important medical milestone since 1840. 150 milestones were short-listed, including the discovery of antibiotics and the development of anaesthesia. And 11000 BMJ readers voted. And which milestone was voted #1, with 15.8% of the votes? The sanitary revolution. Here is a brief excerpt:

The work of the 19th century lawyer Edwin Chadwick, who pioneered the introduction of piped water to people's homes and sewers rinsed by water, attracted 15.8% of the votes, while antibiotics took 15%, and anaesthesia took 14%. The next two most popular were the introduction of vaccines, with 12%, and the discovery of the structure of DNA (9%).

Johan Mackenbach, professor of public health at Erasmus MC Medical Center, Rotterdam, who championed the cause of sanitation, said, "I'm delighted that sanitation is recognised by so many people as such an important milestone. The general lesson which still holds is that passive protection against health hazards is often the best way to improve population health.

...."The original champions of the sanitary revolution were John Snow, who showed that cholera was spread by water, and Edwin Chadwick, who came up with the idea of sewage disposal and piping water into homes.

Inadequate sanitation is still a major problem in the developing world. In 2001, unsafe water, sanitation, and hygiene accounted for over 1.5 million deaths from diarrhoeal disease in low and middle-income countries. Clearly, sanitation still plays a vital role in improving public health now and in the future."

There is something perverse about the current fad for bottled drinking water when clean, safe piped water is available. It is so easy to lose our perspective of our priorities.


Is Healthcare Special? (Part 2)

This post is Part 2 of an earlier post and brings together a few of the thoughts I have been pondering lately. And the issue concerns the primacy a theory of justice ought to place on healthcare rather than health itself. So is healthcare “special”?

I just read an excellent paper in the latest issue of The Journal of Political Philosophy. It was Shlomi Segall’s “Is Health Care (Still) Special?” and he got me thinking about these issues again. Segall’s goal is to take issue with Normal Daniels’s argument that healthcare is special because it has strategic importance in facilitating the pursuit of our life plans. Segall offers two arguments against Daniels. Firstly, Daniels’s specialness account is too narrow (it cannot justify treatment to the elderly). Secondly, it is too wide (many of the opportunities the account depends upon lie beyond the reach of healthcare). I found both of Segall’s arguments persuasive.

Segall also invoked the following useful taxonomy of views:

(1) Most Important: health care resources should be allocated in line with health being the most important good.
(2) Special: health care resources should be allocated in isolation from the distribution of other social goods.
(3) Separate Sphere: health care resources should be allocated in line with the purpose of health care, which is only to promote health.

He also differentiates between two versions (weak and strong) of the Special view:

Strong version: the fact that a person possesses Y ought not affect how much of X she receives.

Weak version: the fact that a person possesses Y ought not determine how much of X is allocated to her.

And it is the weaker version of the specialness account that Segall targets.

I have always been struck by what I see as the paradoxical nature of debates about healthcare reform in Canada. Someone defending the status quo will invoke the specialness account and say something like the following: “Canadians are pretty egalitarian. We (unlike Americans) don’t believe that the rich should be able to buy better healthcare. So we should resist the move towards [more] private healthcare.”

What always puzzles me about this is that those who have such a view do not seem troubled by the fact that Canada has no inheritance tax (nor are lottery winnings taxed ) while the US does (though it is under threat). Furthermore, since the 1990's family income inequality has risen substantially in Canada (see this). I suspect the dismissal of such facts- facts which I think debunk the myth of Canada’s supposed egalitarian commitments- occurs because many Canadians believe that healthcare (unlike wealth and income) is “special”.

So how egalitarian does a commitment to (2) really make a society? And most importantly (since I’m not an egalitarian), how *just* does a commitment to (2) really make a society? Sadly this question seems, in my opinion, to be largely ignored. Canadians take it for granted that the virtues of (2) are self-evident. But I do not believe they are.

What is the problem with treating healthcare as “special”? Segall echoes the concern of Dan Brock (in his excellent KIEJ 2000 article “Broadening the Bioethics Agenda)- that it ignores the broad range of factors that have an influence, and often a greater influence, on our health prospects. These factors include our genetic endowments, stress at work, familial nurture in early life, diet, etc. These are the kinds of factors that I emphasized in my previous posts on Taking People as They Really Are (Parts 1 and 2).

So if healthcare is special to our health prospects then so is the family, education, our diet, etc… And thus singling out heathcare itself for special treatment is really not very helpful (indeed it could do more harm than good). For such a strategy impairs our ability to adopt the “big picture perspective” of these issues.

Who will help Canadians inspire a public debate that transcends the narrow limitations of the “healthcare is special” mantra? Will it come from our political leaders? (I’m not holding my breath!) Perhaps the concerns of the medical profession will help inspire this debate. Or the concerns raised by the Supreme Court.

At least the latter has had the courage to stick its neck out and tell Canadians the reality of the current situation. That is better than simply burying our heads in the sand and pretending that there are no serious problems here.

Healthcare reform is of course much more complex than simply prohibiting or permitting private insurance companies to cover core physician and hospital services (as this informative article argues). ). But by treating healthcare as special we really obstruct the likelihood that any informed, reasoned debate could gain any real steam. And that is why I do not believe that a fair and humane public ethic should treat healthcare as "special"; where "special" means treating healthcare as noted above- by no means am I suggesting that universal healthcare is not important. To continue to treat healthcare as “special” is to fail to give due attention to the other important goals we should be promoting. Goals that also greatly influence the health prospects of our citizens.

Let me conclude by just noting how the issue of healthcare illustrates another point I have been making at various stages on this blog. And this is the point that the principles appropriate for the distribution of anything cannot be determined solely by appeals to “first-best conceptualism”. And that is precisely what the Daniels position does. It takes an abstract principle (in this case Rawls’s principle of fair equality of opportunity) and applies it to one particular good (healthcare). But the problem with this tactic is that a determination of whether or not that is sage advice is not something we can establish by simply pondering what the ideals of equality require. Rather it requires us to do the difficult, complex empirical work needed to get a sense of the kinds of factors that really influence health outcomes. And so it is not surprising that an empirical examination of these issues take us in a direction very different from an idealized, abstract analysis. And this further reinforces how impoverished ideal theory actually is.


Monday, September 24, 2007

Evolving in One Lifetime?

The story of human evolution is a truly amazing story. For some helpful (free) interactive sources on human evolution see the great video here (from ASU's Institute of Human Origins) and this PBS Evolution activity.

To date, the story of evolution has been the story about what happens to a whole organinism. But can evolution happen within a single organism? Today's Nature news has a truly fascinating News piece on this issue by Philip Ball entitled "Why a person doesn't evolve in one lifetime". It is well worth reading, especially if normative theorists are serious about taking people as they really are. Here are a few excerpts from this article:

It's not easy making a human. Getting from a fertilized egg to a full-grown adult involves a near-miracle of orchestration, with replicating cells acquiring specialized functions in just the right places at the right times. So you'd think that, having done the job once, our bodies would replace cells when required by the simplest means possible.

Oddly, they don't. Our tissues don't renew themselves by mere copying, with old skin cells dividing into new skin cells and so forth. Instead, they keep repeating the laborious process of starting each cell from scratch. Now scientists think they know why: it could be nature's way of making sure that we don't evolve as we grow older1.

Evolution is usually thought of as something that happens to whole organisms. But there's no fundamental reason why, for multicelled organisms, it shouldn't happen within a single organism too.

....To renew themselves, epithelial tissues retain a population of undifferentiated stem cells, like the unformed cells present in embryos, that have the ability to grow into different types of cells. When replacements are needed, some of these stem cells divide to make transient amplifying cells (TACs). The TACs then divide several times, and Pepper and his co-workers think that each division produces cells that are a little more developed into mature tissue cells.

All this costs a lot of metabolic energy, so it is not very efficient. But, the researchers say, it means that the functions of self-replication and proliferation are divided between separate groups of cells. The stem cells replicate, but only a little, and so there's not much chance for mutations to arise or for selective pressure to fix them in place. The proliferating TACS may mutate, but they aren't simply copying themselves, so there isn't any direct competition between the cells to create an evolutionary pressure. As a result, evolution can't get started.

Pepper and his colleagues have used computer modelling to show that this proposed mechanism can suppress evolution in a long-lived, multicelled organism.

....The researchers think that their hypothesis could provide new insights into cancers more generally. Whereas conventional wisdom has it that cancer is caused by some genetic mutation that leads cells to proliferate uncontrollably, this new picture implies that the problem would lie with TAC mutations that interfere with differentiation — so that a TAC cell ends up just copying itself instead of producing cells on the next rung up on the way to mature tissue cells.


Friday, September 21, 2007

Aging and Stem Cells

The latest issue of Nature has a very interesting News and Views piece on stem cells and aging. The piece is entitled "Ageing: From stem to stern" by Anne Brunet and Thomas Rando. Here is a sample:

The explosion of research on stem cells has given the promise of treatments for degenerative diseases of ageing, enhancement of the repair of damaged tissues and possibly even slowing of decline-in-function that occurs with advancing age. But how stem cells are affected by the ageing process, and whether such changes are a cause or a consequence of organismal ageing, remain unclear1. Three research teams have recently reported their findings on how age-related accumulation of DNA damage and changes in global patterns of gene expression might lead to the decline of stem-cell function.

....The authors converge in their general conclusions that, with age, adult HSCs decline in function but not number, and that DNA damage and epigenetic modifications may limit the regenerative potential of these cells. They also agree that HSCs are not protected from age-induced damage and, in fact, ageing may result in an accumulation of DNA mutations in these cells, thereby increasing the risk of cancer.
...Would stem-cell 'enhancement', whether genetic or epigenetic, delay the ageing characteristics of a particular tissue or even lead to an extension of lifespan? Understanding what limits stem-cell function during ageing will be essential for the field of regenerative therapeutics, which proffers the hope that the remarkable potential of stem cells will be harnessed for the repair of injury and the treatment of diseases.


Monday, September 17, 2007

Taking People for What They *Really* Are (Part 2)

I wrote this post Friday afternoon while waiting for a flight from Montreal airport. But I’ve just been able to post it this morning:

Earlier today I gave my talk entitled “Genetic Justice: Where to Begin?” to the Montreal Political Theory Workshop at McGill University. Many thanks to Daniel Weinstock and Jacob Levy for their hospitality, and thanks also to those who attended the talk. I really enjoyed the question period. A diverse range of points were raised, and I really benefited from the helpful and insightful questions and comments.

Over lunch with Jacob he mentioned my last post , and asked me to elaborate on what I thought might happen if we really did take our biology seriously. So I thought I should write a few explicit thoughts down here.

Let me begin by stating that I really don’t know where things would take us if we invested more of our intellectual resources into these issues. This is why I love thinking about these issues (and why it is important that we rise to the challenge). But I do have a few hunches concerning what important insights might be reaped. So let me float a few ideas here.

I think the most important thing that taking our biology seriously would do is that it would compel us to re-think what the fundamental principles of morality and justice are. In other words, it would lead us to revise the content of the social contract in important ways—updating it to the realities of the 21st century. And I think that is a pretty good reason to take these issues seriously.

Why do I think such a profound impact would be likely? My reasoning is rather simple-this is likely to be the case because most of the principles and theories on offer have been derived by theorists who have not taken our biology seriously. They either ignored the issue by assuming all people fall within “the normal range” of functioning (and we all know what that means, don’t we?..) or that we could incorporate healthcare into the story of justice by expanding Dworkin’s insurance scheme to cover natural inequalities or simply expand Rawls’s principle of fair equality of opportunity, etc... and this would take care of any complications that might arise. I think that these potential routes are all misguided, primarily because they fail to take people for what they really are. That is, intrinsically vulnerable beings whose expected lifetime acquisition of natural primary goods will be influenced by a complex mixture of external factors (education, diet, lifestyle, etc.) and internal factors (e.g. genetic endowments).

If we take our biology seriously we realize that many different things influence a person’s health prospects. And adopting this “big picture perspective” will, I believe, had a profound impact on our moral and political sensibilities. It might, for example, bring to the fore the importance of the family as an institution. The home environment parents provide their children will greatly impact the physical and mental well-being of their children. From our procreative decisions, to the food we feed our children and their exposure to sports and friendship, the family should play a much more prominent role in contemporary discussions of ethics and justice than it has. And I think taking our biology seriously would help guard against the tendency to ignore or marginalise the importance of the family.

Taking our biology seriously might also show us that stringent *self-regarding* duties apply to us (to be pro-active about our health). This is something every family physician would tell their patients but yet it is something that remains largely absent from the moral landscape in philosophical discussions about ethics. Why? Because doctors, unlike most academic moral/political philosophers, understand how significant our decisions about diet, lifestyle, etc. can be, given the kind of species we actually are.

Following on from these various points…. I think we would realize that a division of labour is required and that this division of labour should receive a lot of attention (it terms of our illuminating what it is, its ethical, social and political implications, etc.). Some things the government can reasonably be expected to do it terms of empowering us to live better, healthier lives. It can help make our working conditions safe, our drinking water safe, implement a minimum wage, ensure there is fair access to basic healthcare and education, etc. And there are many things only people themselves can control (though perhaps the government can indirectly influence)- what we actually consume, our lifestyle, how we raise our children, etc. How we pitch this division of responsibility so that we are attuned to the realities and constraints facing governments and individuals is something we should spend more time pondering.

Another (related) consequence of taking people as they really are is that we would realize how much *perceived* feasibility constraints really influence our stance on what the fundamental principles of justice are. If we ignore the potential benefits of the genetic revolution, for example, then important science policy issues will simply fall off (eh, perhaps it’s more accurate to say would never appear on!) the radar of political theorists.

Anyways, those are a few tentative thoughts on why normative theorists should take people for what they really are. It would help us formulate a new, or at least more updated, social contract.


Friday, September 07, 2007

Taking People for What They *Really* Are

The conception of the person (or self) which a political theory is premised upon can greatly influence the content of a theory. Thomas Hobbes, for example, based his account of the social contract upon a particular conception of the person. According to Hobbes, humans are asocial and naturally suspicious. And this account of the person plays an important role in Hobbes’s political theory. The same could be said for most of the greats in political theory: Locke, Rousseau, Marx….etc.

Fast forward to the late twentieth century, and we can still see this issue at play. The 1980’s and 1990’s was largely dominated by the so-called “liberal/communitarian” debate. An important issue in that debate concerned the conception of the self a theorist employed. To simplify things… many communitarians emphasized the importance of recognizing that we are *social* beings, not the unencumbered persons envisioned in a Rawlsian original position. And this (among other things) spurred many a debate between liberals and communitarians.

Reflecting on the importance the conception of the person has played in debates in political theory got me thinking….. what would happen if theorists took seriously the fact that we are the kind of biological beings we actually are? I don’t mean that to sound as trite as it might sound. We have only really begun to truly understand our biology- like the role genes play in the development of different phenotypes (like health and intelligence), why we develop cancer, why our capabilities decline with age, etc. And as this veil of ignorance is lifted, and we begin to really understand the kind of creatures we are (and could be), shouldn’t we expect our view of the moral and political landscape to also shift in significant ways?

I wonder what would happen if political theorists were to invest as much of their time and energies into the implications of our real biological nature as they have into our purported social/asocial nature? Interesting question. Is this likely to happen? I certainly hope so. But I believe there are a number of reasons why it might not. Probably the biggest obstacle is that contemporary academia makes such interdisciplinary work difficult, or at least it does not provide the kind of incentives needed to foster such intellectual pursuits.

This takes me nicely back to Hobbes. Hobbes really should serve as an example to contemporary political theorists. For Hobbes was greatly influenced by the science of his day. How many contemporary political theorists can truly say that science influences, in a very serious way, their work? The specialization of academic disciplines has, I believe, impoverished our intellectual pursuits in many ways. I long for the day when theorists are, once again, seriously engaged with science. For science will continue to progress, whether we pay attention or not. And I’d like to think that our chances of moving science forward in the right direction is more likely to occur if theorists contribute to (rather than ignore) the public debate concerning where we should take the future of humanity.


Tuesday, September 04, 2007

Venter's Genome

This research article in PLoS Biology describes the genomic DNA sequence from both chromosomes of a single individual- J. Craig Venter. Here is the abstract:

We have generated an independently assembled diploid human genomic DNA sequence from both chromosomes of a single individual (J. Craig Venter). Our approach, based on whole-genome shotgun sequencing and using enhanced genome assembly strategies and software, generated an assembled genome over half of which is represented in large diploid segments (>200 kilobases), enabling study of the diploid genome. Comparison with previous reference human genome sequences, which were composites comprising multiple humans, revealed that the majority of genomic alterations are the well-studied class of variants based on single nucleotides (SNPs). However, the results also reveal that lesser-studied genomic variants, insertions and deletions, while comprising a minority (22%) of genomic variation events, actually account for almost 74% of variant nucleotides. Inclusion of insertion and deletion genetic variation into our estimates of interchromosomal difference reveals that only 99.5% similarity exists between the two chromosomal copies of an individual and that genetic variation between two individuals is as much as five times higher than previously estimated. The existence of a well-characterized diploid human genome sequence provides a starting point for future individual genome comparisons and enables the emerging era of individualized genomic information.

Today's Globe and Mail also has this story here. Here are some excerpts:

Now researchers from Canada, the United States and Spain have decoded all 46 of the chromosomes belonging to J. Craig Venter, the 60-year-old upstart American biologist whose company, Celera Genomics, compiled the private version of the human genome seven years ago. And the results indicate that those first celebrated DNA maps seriously underestimated the genetic diversity of humans - by a factor of at least five.

The new work suggests that the genetic code in the chromosomes we carry can vary widely, not only between any two strangers waiting at a bus stop, but between brothers and sisters.

"The biggest single surprise is how much we missed the boat with the human genome seven years ago, and how different we really are," Dr. Venter said in an interview. "The overwhelming message back then was that we are all like identical clones of each other. ... It's comforting to know we are more unique than that."

....Most experts predict that routinely reading individual genomes will become a reality within five years as the technology to unravel the six billion chemical units that make up DNA gets faster and cheaper.

Kathy Siminovitch, director of genomic medicine at Toronto's Mount Sinai Hospital and the Samuel Lunenfeld Research Institute, noted that the first Human Genome Project rang in at roughly $1-billion (U.S). But with the new generation of "ultra-fast" DNA sequencing machines that have hit the market within the past two years, she said the bill is expected to drop to less than $100,000 by year's end.

Connecticut biotech firm 454 Life Sciences, for instance, has been using the technology to decode the full genome of James Watson, the Nobel laureate who co-discovered the structure of DNA in 1953. That publication is expected later this year.

"It seems like it is possible to think that a $1,000 genome could be within reach," said Dr. Siminovitch, who is buying an ultra-fast sequencer for the University Health Network. "When we see how much variation there is in [Dr. Venter's] DNA, then chances are there is this much variation in all DNA. ... This publication [of the Venter genome] will drive the momentum to get the price down and to be able to do this on lots of people."

The prospect of a $1000 genome is a really exciting one.