Posts Tagged ‘epigenetics’

YouTube Is The New Substitute Teacher

School, like most of everyday life, is at times boring and occasionally a waste of time. We can place blame for that squarely upon the education system and teachers, or share it with parents if we’d like to keep diplomacy in the PTA. But although it’s true that the adults who shape and deliver education as we know it are largely responsible for what we learn and how well we learn it while we are children, we have nobody but ourselves to blame for allowing ignorance to persist after we grow up.

No matter how dreadful your education experience was as a child, if you reached adulthood literate enough to use the internet, then you should find developing a passing acquaintance with basic science concepts both convenient and entertaining. The idea that learning should be fun and easy is so compelling that YouTube is positively swarming with video bloggers enthusiastically sharing knowledge.

Because I am a science enthusiast and a lifetime devotee of independent study, I’ve compiled a video playlist of some of my recent favorites in that genre. To eliminate some common misconceptions, the playlist opens with the definition of science. From there, it builds from some interesting basics about water and carbon, covers some of the science frequently botched by Hollywood and in other fiction, and demonstrates that girls plus math equals win. Then follows a musical interlude, but it’s all science, so it’s all good. The last few are a sampler of videos posted by universities and science publishers for viewers who prefer productions with bigger budgets.

Now all you have to do is watch and learn.

Southpaws: The Hops in Humanity’s Beer?

This is the first article in a series that explores the attribute of chirality (handedness), which is intrinsic to life across scales yet surprisingly absent from speculative fiction (the single time I recall a plot point hinging on it is during Mal’s battle with the Operative in Serenity).  A version of it appeared on Huffington Post.

“Light is the left hand of darkness…” – Ursula K. Le Guin

Those who are, like me, left-handed and older than fifty probably recall being forced to write with our right hand and the frustration of using many “handed” tools, including scissors, rulers and computer mice. We also remember being told that left-handers are prone to immune deficiencies, shorter lives, depression, dyslexia, schizophrenia and a host of other woes… and no wonder, given the drizzle of harassment! Finally, there is the conflation of left with evil, wrong or inept in practically all religions and languages (sinister, gauche, linkisch…) not to mention most political systems, especially those which place high value on obedience and conformity.

Left-handedness is genetically determined, although controversy swirls around candidate genes that have been tentatively linked to the trait and the complications supposed to accompany it – most prominently a protein with the impressively lengthy name of Leucine-Rich Repeat Transmembrane Neuronal 1. LRRTM1 is involved in regulation of the synapses, the tips of the neuronal processes where exchange of information takes place by molecules bridging the gaps between cells. Other theories propose that left-handedness may arise from exposure to increased testosterone during gestation. Yet others attribute it to the asymmetry of the human brain, brought about by the appearance of language whose centers almost invariably reside in the left hemisphere (which regulates the right side of the body).

In contrast to the even distribution of paw preferences in our ape cousins, the percentage of human left-handers hovers around 10% regardless of race and culture. The most common explanation for the persistence of the trait was that left-handed warriors had the element of surprise in primitive societies. As a result of this sneakiness, they survived long enough to leave a few like-handed descendants. Notice that this explanation is exclusively male-oriented and also implies that the trait is both monogenic and dominant. In fact, LRRTM1 is maternally silent – but at least in my case, I know that I inherited my quasi-ambidexterity (loaded word!) from my mother’s side.  On the other hand, nobody who has met me can conclude that I’m low on testosterone.

From my professional knowledge of biology and my own awareness of what strengths and weaknesses I possess, I hit upon a slightly more flattering explanation for the persistence of the trait. Namely, I decided that left-handed people must be less lateralized in their thinking. This can lead (literally) to crossed brain wires – and hence to such outcomes as dyslexia. But it can also lead to less mental compartmentalizing, more efficient multi-tasking, enhanced ability to see the big picture and to think across boundaries.

Recent results from several neurobiological disciplines lend support to these speculations. Apparently, left-handers do cluster at the two ends of the IQ range; the connections between the two sides of their brain are faster than in right-handers; they often use both hemispheres for language; and they excel at complicated tasks. Lists of southpaws in history show that they are disproportionately represented among mathematicians, scientists, artists and, for better or for worse, among charismatic leaders — from Alexander the Great to Jeanne d’Arc. Moreover, a disproportionate ratio of US presidents since WWII have been southpaws, partly because schoolchildren in an increasingly un-corseted culture were no longer forced into right-handedness. So left-handers may not be a relic of barbaric times, after all. Instead, they may be the hops that add zest to humanity’s beer.

Images: top, Southpaw by RobtheSentinel; bottom, an illustrious left-hander — Marie Sklodowska Curie, Physics Nobel 1903; Chemistry Nobel, 1911.

You Are What Your Granddad Ate

You are more than the sequence of your genes.

No one should find that particularly controversial: there are differences between genetically identical twins, after all, and the concept of X-chromosome-inactivation (with an obligatory picture of a calico cat) was part of my high school intro bio class a quarter century ago. It also shouldn’t come as a surprise that in multicellular organisms like humans, different types of cells express different genes, even though their DNA is the same.

Diet and environment can induce some of those changes. For example, there are compounds in broccoli that can potentially prevent cancer by altering the packaging of DNA. And smoking tobacco can cause modifications of your DNA that likely increase the risk of cardiovascular disease long after you quite smoking. These changes are considered “epigenetic” rather than “genetic”, because they alter gene expression through the addition of small chemical groups to the DNA or to the proteins that bundle the DNA, rather than by altering the DNA sequence itself.

I’m sure some of you reading this are thinking that this isn’t particularly exciting. We all know that eating vegetables is good for your health and smoking is bad for your health, no matter what biochemical changes are going on inside your cells. But there’s more to it than that. What has brought epigenetics recent attention in the popular science press recent studies showing that epigenetic changes are heritable.
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