This is a trial run (I hope!)

Early Pleistocene enamel proteome sequences from Dmanisi resolve Stephanorhinus phylogeny:

Ancient DNA (aDNA) sequencing has enabled unprecedented reconstruction of speciation, migration, and admixture events for extinct taxa. Outside the permafrost, however, irreversible aDNA post-mortem degradation has so far limited aDNA recovery within the ~0.5 million years (Ma) time range. Tandem mass spectrometry (MS)-based collagen type I (COL1) sequencing provides direct access to older genetic information, though with limited phylogenetic use. In the absence of molecular evidence, the speciation of several Early and Middle Pleistocene extinct species remain contentious. In this study, we address the phylogenetic relationships of the Eurasian Pleistocene Rhinocerotidae using ~1.77 million years (Ma) old dental enamel proteome sequences of a Stephanorhinus specimen from the Dmanisi archaeological site in Georgia (South Caucasus). Molecular phylogenetic analyses place the Dmanisi Stephanorhinus as a sister group to the woolly (Coelodonta antiquitatis) and Merck’s rhinoceros (S. kirchbergensis) clade. We show that Coelodonta evolved from an early Stephanorhinus lineage and that this genus includes at least two distinct evolutionary lines. As such, the genus Stephanorhinus is currently paraphyletic and its systematic revision is therefore needed. We demonstrate that Early Pleistocene dental enamel proteome sequencing overcomes the limits of ancient collagen- and aDNA-based phylogenetic inference, and also provides additional information about the sex and the taxonomic assignment of the specimens analysed. Dental enamel, the hardest tissue in vertebrates, is highly abundant in the fossil record. Our findings reveal that palaeoproteomic investigation of this material can push biomolecular investigation further back into the Early Pleistocene.

Dmanisi. If that doesn’t mean something, look it up!

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3 thoughts on “This is a trial run (I hope!)

  1. My jaw is still dropping, pardon the near-pun. After seeing your RT, I read up on paleoproteomics, and some practitioners are even claiming results going back tens of millions years, to the Cretaceous?! I can scarcely even believe the more readily accepted 3.8m year window…I had thought that fossilization was entire mineral replacement, leaving only outlined anatomic Structure, with maybe some scrambled trace signals of hydrocarbon organization, but not entire, readable, Original Content!

    What effect might this practice have on cladistics as we know it, beyond just your specific interest in hominims? Would you care to speculate? The reason I started following you is because you are not entirely beholden to academia’s requisite understatement, heh.

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  2. re: some of the more audacious claims turned out to be wrong. but this looks legitimate. ppl who know the field agree the methods check out. ancient DNA has limitations. it looks like proteome may go a little further. a few million years is going to offer up a lot of opportunities, because aDNA time depths are kind of shallow to really figure out phylogenetic patterns.

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  3. I have no dog in this fight, but I remain intrigued by your entirely firm dismissal of mega deep time claims, contra these two ‘civilian’ articles of recent vintage–(late 2017-early 2018, see bottom) which I had encountered in attempt to autodidact upon reading of the rhino-enamel result, was why I felt okay to mention mega-deep time ‘reads’ as a still-present possibilty.

    I anticipate that you’ll inform me that these publications are considered POS among real scientists, and these articles are object lessons in sci-journalism malfeasance. The articles seem to argue both sides pretty well, giving skeptics very fair length, but leaving off with particularly *Capellini’s attempt to replicate* still unannounced? Civilian Google search yielded nothing definitive regarding Capellini’s recent-ongoing attempt..

    Appreciate that you are taking the time to engage with/disabuse a mere layperson.

    Again, I agree that mega deep time seems even more fantastical than 3.8m claims, which more modest longevity already strains credulity.

    1) http://www.the-scientist.com/features/paleoproteomics-opens-a-window-into-the-past-30026/amp

    2) http://www.sciencemag.org/news/2017/09/i-don-t-care-what-they-say-about-me-paleontologist-stares-down-critics-her-hunt

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