tag:blogger.com,1999:blog-1812431336777691886.post229360870179267917..comments2024-02-29T03:57:00.088-05:00Comments on The Mermaid's Tale: Why does genetic determinism persist, in spite of the evidence?Anne Buchananhttp://www.blogger.com/profile/09212151396672651221noreply@blogger.comBlogger4125tag:blogger.com,1999:blog-1812431336777691886.post-59367420760966448362013-06-17T07:35:32.405-04:002013-06-17T07:35:32.405-04:00People want simple answers to complicated question...People want simple answers to complicated questions.Ken Weisshttps://www.blogger.com/profile/02049713123559138421noreply@blogger.comtag:blogger.com,1999:blog-1812431336777691886.post-56666041293163040732013-06-12T15:19:34.893-04:002013-06-12T15:19:34.893-04:00The problem is people think of genes and the expre...The problem is people think of genes and the expression of genes as one in the same. Which it isn't, and it's really painfully obvious because as we age our bodies and even minds change, we shed ideas and adopt new ones, and our brains rarely keep much of a record of this. Our brain usually goes "here we are, here's where we've always been". <br /><br />It's really stupid when you think about it. Do people ever find themselves waking up fat, or waking up magically intelligent? Did Michael Jordan just wake up one morning a basketball phenom. No, he even says so himself in the commercial "Maybe it's my own fault". "Basketball wasn't some God Given gift, it was something I worked for. Every single day of my life". <br /><br />Bottom line is most people are lazy, usually across the board. Lazy thinkers, lazy workers, and lazy television watchers. They want quick results, so genetic determinism makes this seem like a reality to them. What better way to be a great Politician if you're just born one. What better way to know your son will be quarterback than if his genes say so. <br /><br />I think really what you're witnessing is that people who work hard are and probably have been few and far between. The age of the internet has brough forward all the whiners and people claiming they're "born this way", because most people who would idle there time on here are the same as those plopped in front of the idiot box (television) and likely the same who wouldn't been Lion chow 10,000 years ago.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-1812431336777691886.post-4830526095172448132010-02-26T19:23:54.815-05:002010-02-26T19:23:54.815-05:00We write about the problems with GWAS a lot. Ther...We write about the problems with GWAS a lot. There are people trying some clever statistical tricks--ooops! after climategate I better not use that word!--statistical approaches that try to get all the data contained in all the GWAS SNPs. They will find some things, and they'll get as much juice as there is in the SNP-stone. Predictive power will increase but, as a couple of papers have aptly put it, one can't really get much better than the level of heritability (usually way less than 50%) of traits, and even if risk predictions from GWAS genotypes get a lot better, they mostly will not be usefully gene-specific: they'll be aggregate or 'polygenotypic' effects, differing for everyone even with the same risk score<br /><br />As to epigenetics, one could also enumerate other nonstandard 'genetic' effects, like various complex RNAs (some acting in 'trans' as well as 'cis') that current methods aren't really looking for.<br /><br />The epigenome means different things to different people. Understanding heritable DNA modification effects that are heritable will be one source of new information--but also new complexity since it won't generally reduce the complexity we already have in DNA sequences (at least, I think that's what'll happen).<br /><br />Also, many 'genetic' effects are stochastic and somatic, and this applies to mutation and epigenetic changes. Many studies show that stochastic changes during development can have major mosaic effects (classic recent studies involve agouti mice).<br /><br />But it's not clear to me what you have in mind, because if the stress-related changes arise, will they not be during life and tissue specific? If so, how an you ascertain them? It seems to be similar to trying to ascertain precancerous cells lurking within an otherwise normal tissue. <br /><br />The final example you gave illustrates what many are certainly finding: early life changes with later life effects. They won't be found by mapping, perhaps, but how we would detect them, much less understand their cause is a question; perhaps you have ideas about this. Or perhaps if we can test the right tissue somehow maybe we don't need to know what the cause was.Ken Weisshttps://www.blogger.com/profile/02049713123559138421noreply@blogger.comtag:blogger.com,1999:blog-1812431336777691886.post-73067459111700543462010-02-26T19:08:36.983-05:002010-02-26T19:08:36.983-05:00You have identified the "missing heritability...You have identified the "missing heritability" problem that is becoming increasingly apparent as more GWAS are being performed with higher sample numbers: the strength of association between a trait and genotype reaches some statistical significance but has little or no clinical utility. <br /><br />It's important, however, to note that there is another layer of information within the genome that GWAS do not presently investigate - the epigenome, which carries heritable changes in the DNA and histone proteins that are not associated with DNA sequence. This class of modifications can arise even after a brief exposure to an environmental stressor at developmentally sensitive periods and are the direct imprint of the environment on the genome. Evidence from the science of epigenetics supports a case a against genetic determinism yet interestingly, such genetic changes are easily detectable. <br /><br />This brings us to the matter of epigenetic determinism and why it is that what your grandmother ate whilst your mother was a foetus - but was also developing her eggs - may determine your risk of metabolic syndrome today.Harry Banaharisnoreply@blogger.com