GREAT science writing

A Brief History of Everyone Who Ever Lived
by Adam Rutherford

This guy is a magnificent science writer! I am stunned at the complex ideas he can explain and illustrate and entertain me with. There's a lot of stuff in this book--lots of a lot--and I can only take time to point out a couple of things that absolutely floored me.

The first section of the book deals with ancient man-like creatures and it whacked me in the head with the reminder than our evolution was never linear--it was loopy. It lines up in a neatly branched family tree only when populations become isolated and stay that way. Mankind didn't. When the last group of modern humans left Africa, they met with Neanderthals and Denisovans and who-knows-what-yet-to-be-discovered species out there, and mated with them. You see it in our genes.

Also note: the vast amount of genetic diversity today occurs in Africa, but it was only a small sample of humans that emerged to populate the rest of the world. So a dark-skinned North African might have more genes in common with a Swede than he does with his dark-skinned South African neighbor.  If you feed the counts from the human genome project into a computer program and ask it to group them into six groups by similarity, it returns results that appear to follow the traditional racial groups.  But when you increase the number of groups, then small, isolated tribes begin to emerge, and they're nothing we would consider to be "racial" groupings. For example, with seven groups selected, one might say the seven major races of man are African, European/Western Asian, East Asian, Australian, American, and Kalasha.  (A northern Pakistani tribe of about 4000 people.) If you go to seven or more, it gets less and less like what we'd have expected.

Having eliminated race, he takes up inbreeding.  I never considered the notion that royal families--both European and Central/South American--are shockingly inbred. The classic case is the Spanish royalty's Hapsburg dynasty. Charles II was the last of the Hapsburg dynasty--he failed to produce an heir after two marriages, dying at age 39, bald, crippled, epileptic, and nutty.  Most likely because they started inbreeding more than a century before his birth. His line suffered a severe case of "pedigree collapse."  See this article:

http://blogs.discovermagazine.com/gnxp/2009/04/inbreeding-the-downfall-of-the-spanish-hapsburgs/

The inbreeding cooeficient is the average number of the genes which are the same on both their paris of chromosomes. For a brother-sister pairing, this value is .25. A team of geneticists calculted Charles II's inbreeding cooeficient as .254. (His mother and grandmother were pretty looney, too.)

Even more exciting is his description of epigenetics--the inheritence from parent to child of epigenetic factors, those which enable or prevent the expression of genes. I'd never realized these factors could be inheritied, but there's evidence of it. It's only partially inherited, and it's not permanent in the way of genes, but there are clearly demonstrated cases.

Lest you read this and jump on epigenetics as the latest "scientific breakthrough bandwagon", he cleverly notes:
But, as sometimes happens in science, it's also a field that has been exposed and leapt upon in a press frenzy to attempt to explain all sorts of as yet unsolved mysteries of biology. The legion purveyors of ackamarackus love a real but tricky scientific concept that they can bolt their quackery onto. It happens with words like quantum, which offers up some magical scienceyness, none more so than in quantum healing--an unfathomable extension of reiki, which, let's face it, is a load of old cobblers already. The annexing of this word from fundamental physics also ranges from washing powder branding to the theory of mind.

He gives more examples, but I'll leave it at that.