Saturday, October 8, 2016

Proteomics proves Neanderthals made jewelry!

Need a way to put that cousin you have that left his/her stable job at the accounting firm to find him/herself to make surprisingly complex silver wire jewelry into some sort of context?

Now, I'm not going to go putting Neanderthals down or anything, especially after this nice animation that greets me when I go and check on the new 23andMe features they've added....

...sigh...  You know, if  I was a more sensitive guy, I might actually consider that somewhat stereotypical caricature of what is apparently my ancestors a little insulting.  

Back on topic!  Okay, so I'm going to have to swallow what is left of my pride and admit that I don't get the central premise of the paper I'm talking about. This historical dig has been highly controversial. People have been digging stuff here for like 40 years or something and no one buys the radiocarbon dating cause they think the layers of deposition might be mixed up. So...what I'm missing here is how proteomics can make this clearer. But it made it into PNAS and got a nice review in Science so I'm gonna guess the experts on that side of things are cool with it!

What I do get is this -- the darned Neanderthals produced collagen that is different than ours -- well... yours, I guess!  Human collagen has tons of aspartate (D) in it. But neanderthals primarily substitute D for N (asparagine) --or vice versa, I read this on a boat today and didn't take great notes. know...the caveman thing....

Okay! So that's easy, right? We can definitely tell if a D is N, that is a 20mmu difference or whatever.

So I'm super excited about this paper and then I get the PNAS paper and its and I keep seeing the words "MALDI-TOF" as I go through it. Which makes me just a little stressed because I'm afraid a paper getting mainstream attention might be looking for a 20mmu peptide difference with an instrument that is only accurate to 100mmu (if it is calibrated every half hour or so) but on page 3 of the supplemental info you'll find that they used LC-MS on a Q Exactive and I chill out. 

Like most PNAS papers, this one has about 100 pages of supplemental info, including some nice MS/MS spectra cut from PEAKS that support their D to N substitutions. This is a really solid and interesting paper all the way around. 

"Sweet earrings cousin Pat! You know who else made jewelry...?"

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