Wednesday, August 9, 2017

I Have Been Evolving

A recent article published in BMC Biology presented evidence that 450 million years ago the common ancestor of present-day Spiders and Scorpions experienced a Whole Genome Duplication (WGD). 

A Whole Genome Duplication is when the offspring of an organism accidentally gets two complete copies of its genome, which its descendants then inherit.  While relatively rare, WGD's do occur from time to time, but usually don't lead to anything since by itself it provides no advantage to the individual.  However if the double genome hangs around for long enough before going extinct, it can provide twice the opportunity for evolution to test mutations while having a bit of a safety fallback in the form of the duplicate gene.  At least I think that's how it works.  

This pre-spider WGD seems to have been an advantageous one since probably all spiders and scorpions alive today are descended from it. WGD can essentially confer evolutionary superpowers on a line of organisms, enabling them to diversify rapidly and specialize dramatically. This is certainly true of spiders, of which there are an estimated 46,000 distinct living species, with many more yet to be discovered and classified. If you name any possible way to survive in nature, there's probably a spider that does it.

But that's nothing.  We vertebrates had TWO WGD's in our evolution. And look at us - we invented bug spray.  Take that, spiders.

I find evolution fascinating.  As Francis Crick put it, "Evolution is smarter than you."  Using nothing more than lots of time, lots of slightly imperfect gene duplication, and razor-sharp selective pressures, it results in incredibly subtle and clever solutions to the problem of survival.  

The turning point in our history was when we Eukaryotes decided it would be fun, instead of simply eating a bacteria, to adopt one as a pet and let it live inside our membrane. That's how we came to have things like chloroplasts, mitochondria, and golgi bodies inside us.

A similar thing happened to us again about 10,500 years ago when, instead of simply killing and eating an aurochs, we decided to try catching some and keeping them as pets. We would feed them, watch them mate, keep them alive, and then get lots of little baby aurochsen. That is the day we invented Veal. 

The lesson in all this is to never do anything exactly the same way always.  Change it up a bit.  Find what else works.

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You Are Here: humans are the tip of a tiny twig on one of the right-hand limbs of the right-most branch.


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