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DNA sequencing has revolutionized the way researchers study evolution and animal taxonomy. But DNA has its limits—it's a fragile molecule that degrades over time. So far, the oldest DNA sequenced came from a 700,000-year-old horse frozen in permafrost. But a new technique based on the emerging field of proteomics has begun to unlock the deep past, and recently researchers extracted genetic information from the tooth enamel of a rhinoceros that lived 1.7 million years ago.
The new proteomics approach is essentially reverse engineering. Using a mass spectrometer, researchers look at preserved proteins and are able to determine the amino acids that make them up. Because researchers know what three-letter DNA sequence encodes each amino acid, they can then determine the DNA sequence for the protein.
"It's reading DNA when you don't have any DNA to read," Glendon Parker, a forensic scientist at the University of California, Davis, says in a press release. He and colleagues are developing proteomics techniques that can be used in criminology, evolutionary biology and anthropology. "Protein is much more stable than DNA, and protein detection technology is much better now."
The most stable protein that we know of is tooth enamel, which can remain intact in fossils for millions of years. Enrico Cappellini of the University of Copenhagen and colleagues focused on this protein in a new study in the journal Nature. The researchers took a miniscule amount of enamel from the tooth of a 1.77-million-year-old Eurasian rhinocerous species called Stephanorhinus, which was dug up in Dmanisi, Georgia. The DNA had long since degraded, but mass spectrometry allowed the team to retrieve genetic data from the enamel, the oldest ever to be recorded, according to another press release.
(Score: 4, Informative) by HiThere on Friday September 13 2019, @06:03PM (1 child)
OK, but that's not the real problem. The real problem is that they aren't sequencing the genome, but only fragments from it. So much of the information isn't there to recover. You'd need to go all Jurassic Park, and presume that a modern rhino's genes could fill in form the missing ones, and that's likely wrong.
Of course, it depends on your purposes. Perhaps that's good enough.
That said, proteins are usually more stable than DNA, so you can often reconstruct parts. Don't assume it will match the original, though, because of missing parts, e.g. because of exons. That you use a synonymous codon will (should?) only affect the stability of the generated DNA, except in cases where one variety would cause it to form a hairpin curve or some such.
Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
(Score: 2) by Osamabobama on Friday September 13 2019, @08:10PM
My purposes are to stage a true-life version of Eugène Ionesco's classic play Rhinoceros [wikipedia.org]. I figure I'll just fill in the missing pieces with human DNA.
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