“Because the history of evolution is that life escapes all barriers. Life breaks free. Life expands to new territories. Painfully, perhaps even dangerously. But life finds a way.”
― Michael Crichton, Jurassic Park
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| Ian Malcolm: From Chaos by John Larriva & more Jurassic Park inspired art: http://brandonbird.com/jp_show.html |
this past spring, i decided to take an online genetics course. again and again, discussions of ethics came up and naturally, i resumed thoughts on 'playing god' and of course, jurassic park.
one of the topics that came up was genetic testing for trisomy 21. down syndrome. if you can prevent it, should you? many disorders/ diseases aren't so clear cut. more than likely, you'll hear there is both a genetic and environmental component. however, more and more research is finding that certain anomalies, SNPs and allele variations may put one at a higher risk for diseases and disorders. but if you could prevent it... should you?
per usual, Emily Deans, M.D. posted an interesting read on the counter intuitive nature of depression.
Depression- A Deal with the Devil, begins with allele 308A that is associated with an increased risk of depression. What's curious is that it is also associated with a decreased risk of tuberculosis which would have been quite advantageous before modern medicine. that allele variant also decreases one's risk for parovirus B19, hepatitis B and for some reason, lowers risk of death when hospitalized when seriously sick.
another area of interest is apolipoproteins. they are proteins that bind lipids such as fat and cholesterol, forming lipoproteins that then carry the lipids throughout the lymphatic and circulatory systems. again we find that certain alleles put one both at risk but also at an advantage. people with the ancestral allele, ApoE4 are more susceptible to Alzheimer's and depression but then instead, are protected against childhood diarrheal illnesses, which were often lethal. unlike ApoE4, the ApoE2 allele seems to be protective against general inflammation but leaves one more vulnerable to tuberculosis and malaria.
one of the first found genetic correlates with depression and the most studied, are alleles associated with 5HTTLPR. this gene is what tells cells to make serotonin transporters. any psychology major will tell you, serotonin is kind of a big deal. we know that serotonin and dopamine are involved in mental health but why people have low/high levels of certain neurotransmitters is the far more interesting question (and more difficult to unravel).
those with one and especially two short alleles are more susceptible to depression after trauma but seem to have a lower risk of dying from SIDs (sudden infant death syndrome). another interesting tidbit is that those individuals with either 1 or 2 short alleles, respond with more cytokines to stress which would have been adaptive in a pre-modern medicine world when one was wounded/ infected. it shouldn't be surprising then that in areas where epidemic infections are more common, the short allele is more common among inhabiting populations.
in addition to the sneaky evolutionary benefits of depression Emily Deans, M.D. addressed, creativity has often gone hand in hand with melancholy. many studies have found an increased rate of bipolar and depressive illnesses in highly creative individuals. its not really a case of mental illness causing creativity or the creative mind making one prone to mood disorders. its more likely that the genes that influence obsessive tendencies, rumination, abstract thought, etc. that coalesce into creativity, are also what make one more vulnerable to mood and anxiety disorders.
would john nash (a beautiful mind) have had such a beautiful mind without his schizophrenia? perhaps it was the surplus of dopamine that influenced his theories that today are so frequently used in areas such as market economics, computing, evolutionary bio, AI, accounting, politics and military theory.
would actors, artists, comedians and writers be better off without their struggles with mood disorders or is it those struggles that have ultimately make them so damn good at what they do?
what makes us susceptible to one thing, gives us an advantage for another. in the game of evolution, all that (genetically) matters is being able to survive until reproductive age. what may have been adaptive 100, 1,000, 10,000 or 100,000 years ago may not be quite so beneficial today. we must be weary when attempting to assign good/bad judgements to traits and genes. genetics has come a long way and has a long way to go yet.
it's not enough to know what genes do. WHY things happen is the far more important question. before we even think about playing god and manipulating genes, it's imperative that we understand the evolutionary reasons why we are the way we are. if we get too hasty, we just might find some unintended consequences.
after all, the road to hell was paved with good intentions.
interesting & FREE read:
The Evolutionary Significance of Depression in Pathogen Host Defense (PATHOS-D)
http://www.nature.com/mp/journal/vaop/ncurrent/pdf/mp20122a.pdf
more info:
http://en.wikipedia.org/wiki/List_of_people_with_bipolar_disorder
http://en.wikipedia.org/wiki/Major_depressive_disorder
http://en.wikipedia.org/wiki/Major_depressive_disorder
http://en.wikipedia.org/wiki/Apolipoprotein
http://en.wikipedia.org/wiki/List_of_people_with_major_depressive_disorder
http://en.wikipedia.org/wiki/Unintended_consequences
http://www.ncbi.nlm.nih.gov/pubmed/18689294
http://en.wikipedia.org/wiki/List_of_people_with_major_depressive_disorder
http://en.wikipedia.org/wiki/Unintended_consequences
http://www.ncbi.nlm.nih.gov/pubmed/18689294
http://www.psychologytoday.com/blog/evolutionary-psychiatry/201208/depression-deal-the-devil?
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