TOP 100 SCIENCE SITES
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| Famed Tasmanian devil euthanized after tumor found By KRISTEN GELINEAU 2010-09-01T07:44:54ZSYDNEY (AP) -- A Tasmanian devil named Cedric, once thought to be immune to a contagious facial cancer threatening the iconic creatures with extinction, has been euthanized after succumbing to the disease, researchers said Wednesday.... hosted.ap.org |
Experts fly to Japan to probe panda death A team of Chinese experts have reportedly arrived in Japan to investigate the death of a giant panda which was on loan to a Japanese zoo. abc.net.au |
World's 'oldest bird' ringed on Shetland A whimbrel ringed on a Shetland island in 1986 is now believed to be the world's oldest surviving bird of its kind. bbc.co.uk |
Genes Are Political Agnostics Genes are apolitical, but society is not. To understand and respond as a society to individual genetic differences, we must understand the environment where these genes are expressedLast night I was up later than usual, finishing a review of a manuscript that estimated how much genes influenced body size, using data from real, wild populations (wild? After what was done to that population, they must be livid). During one of my frequent breaks, I saw this twitter comment, from Mark Henderson, science correspondent at The Times:Oliver James demolishes another straw man... http://bit.ly/aTuMlXA couple of minutes later, when I took my next break, I followed the link. Henderson was only sort-of accurate about Oliver James demolishing a straw man. If you know anything about the subject, it was clear that he wasn't even attacking the straw man he was setting up: he was tilting at a windmill that he mistook for the straw man he had set up.James' Comment is Free piece resurrects the straw man of the old nature-nurture debate. Is human behaviour determined by genes or by the environment? We've pretty much answered this: "it's more complicated than that". Both genes and environment have an effect, and it's going to be messy (genes can change susceptibility to having a psychiatric disorder, but growing up in a bad environment will make it more likely that you will actually suffer from psychiatric problems). The interesting genetic questions surround the relative importance of different genetic and environmental effects, and finding the genes that are involved in genetic disorders.James erects this straw man of genes or environment, and declares that genetics is wrong:When the map of the human genome was presented to the world in 2001, psychiatrists had high hopes for it. Itemising all our genes would surely provide molecular evidence that the main cause of mental illness was genetic – something psychiatrists had long believed. Drug companies were wetting their lips at the prospect of massive profits from unique potions for every idiosyncrasy.But a decade later, unnoticed by the media, the human genome project has not delivered what the psychiatrists hoped: we now know that genes play little part in why one sibling, social class or ethnic group is more likely to suffer mental health problems than another.(I'm sceptical that psychiatrists, as a group, were genetic determinists but I'm not a psychiatrist so I don't really know)He then lays out evidence like this:In 2009 Professor Robert Plomin, a leading behavioural geneticist, wrote that the evidence had proved that "genetic effects are much smaller than previously considered: the largest effects account for only 1% of quantitative traits". andIn Sonuga-Barke's own field, attention deficit hyperactivity disorder, he observed that "even the most comprehensive genome-wide scans available, with thousands of patients using hundreds of thousands of genetic markers … appear to account for a relatively small proportion of disorder expression".andThat was illustrated recently in a heavily publicised study by Anita Thapar, of Cardiff University. Although she claimed to have proved that ADHD is a "genetic disease", if anything, she proved the opposite. Only 16% of the children with ADHD in her study had the pattern of genes that she claimed causes the illness. Taken at face value, her study proved that non-genetic factors cause it in 8 out of 10 children.But ADHD does have a genetic component. How do I know? Because I googled "ADHD heritability". Heritability is (roughly) the proportion of variation in the trait (here the propensity to get the disorder) that is genetic. Amongst the hits was this one which says Concordance of ADHD in monozygotic twins is greater than in dizygotic twins, suggesting some contribution of genetics. Studies estimate the mean heritability of ADHD to be 76%, indicating that ADHD is one of the most heritable psychiatric disorders. (link added)and other hits back this up. So these studies say that James is wrong. Genes do have an effect on ADHD (similar results have also been found for other psychiatric disorders). But what about these quotes that James uses?Anyone who's been following human genetics in the last couple of years (e.g. these guys) can see what's going on -- the second and third quotes aren't about genetics per se. The first one is a quote mine: here's the full paragraph that quote came from:GWA studies suggest that for most complex traits and common disorders genetic effects are much smaller than previously considered: The largest effects account for only 1% of the variance of quantitative traits. This finding implies that hundreds of genes are responsible for the heritability of behavioural problems in childhood, and that it will be difficult to identify reliably these genes of small effect. Another discovery with far-reaching implications for future genetic research is the importance of non-coding RNA (DNA transcribed into RNA but not translated into amino acid sequences), which redefines what the word gene means. Non-coding RNA underlines the need for a genome-wide approach that is not limited to the 2% of DNA responsible for specifying the amino acid sequences of proteins. (emphasis added)The correct response to reading this is not "Plomin says there are no genetics effects", but rather "huh?"What confused James is one of the problems that human geneticists have been finding recently. They find (from twin studies) that there is genetic variation -- there is heritability -- but when they try to find the genes involved, the genes they do find only account for a small proportion of the heritability they have measured. Bummer.Now, there are some good explanations for why we may be missing a lot of genes (Razib gives a short summary here): these traits are affected by a lot of genes, and so they may have small effects that are difficult to pick up from genomic studies, or genes could have fairly large effects, but they are rare, and hence difficult to pick up from these studies. Or it might be a lot more interesting (or messy!) than this. It's still an active area, and I haven't seen a resolution: it's a big problem that needs a lot of research before we get a good handle on what's happening (for that we need funding, so support our vital Science!).James erected this "nature or nurture" straw man, and then tilted at the windmill that was the few big genes we can see. At the moment, genomics can only show us the bigger strands that make the frame of the straw man, and they can look like a windmill. Which is (perhaps) why he is wrong here:Politics may be the reason why the media has so far failed to report the small role of genes. The political right believes that genes largely explain why the poor are poor, as well as twice as likely as the rich to be mentally ill. To them, the poor are genetic mud, sinking to the bottom of the genetic pool. (isn't that a straw man position of the political right? I would make more of it, but I can't think of another metaphor to throw into the mangle). But even if genes do influence mental illness, would the rightwing straw man still be correct?  Perhaps not. Firstly, even if 76% of genetic variation is genetic, that still leaves 24% unexplained: there is an environmental effect that can be changed. Secondly, these studies are made on "natural" human populations. One thing we sometimes forget when doing these studies is that the results are specific to the environment they are measured in. I have mainly worked with data collected in the laboratory, and we always have to remember that the lab is not the same as the field; it's a different environment. So, even if in the observed environment variation in ADHD prevalence may mainly be genetic, that does not mean that we can't change the environment beyond what was in these studies to reduce the overall prevalence: for example we could reduce poverty and create a more equitable society where all genes will feel equal and will be able to live out their socialist selfish existence. Even if the poor were to be "genetic mud", that wouldn't mean their lives couldn't be improved and Great Things be encouraged to sprout from their fertile genetic soil.Unlike James, I don't think genes are leftwing. For me, they are apolitical. But their story does need to be understood: whether a politician is on the left or right, they still live in the real world, and if their policies are to be effective, they have to understand the real world. Even within the constraints of reality, there will still be enough wiggle-room for different political philosophies to suggest actions that could be taken to combat problems like mental health issues. But, please, understand the science first. And please don't distort it.Bob O'Hara is a biostatisician working at the Biodiversity and Climate Research Centre in Frankfurt am Main, Germany. He lives with 5 parrots, 2 aquaria, a cat, and one GrrlScientist. He usually blogs at Deep Thoughts and Silliness.GrrlScientistguardian.co.uk © Guardian News & Media Limited 2010 | Use of this content is subject to our Terms & Conditions | More Feeds guardian.co.uk |
Clever crows go to 'tool school' Young New Caledonian crows learn to use tools by going to "tool-school", where they can observe their parents at work. news.bbc.co.uk |