Seismosaurus proteins: bone of contention.
Fossil bones from the longest dinosaur known have yielded proteins that apparently survived intact for 150 million years, geochemists reported last week. If bolstered by future work, this controversial claim could open up new methods for studying the evolutionary relationships of long-extinct animals.
W. Dale Spall and his colleages at Los Alamos Los Alamos (lôs ăl`əmōs', lŏs), uninc. town (1990 pop. 11,455), seat of Los Alamos co., N central N.Mex. It is on a long mesa extending from the Jemez Mts. The U.S. (N.M.) National Laboratory chemically extracted the proteins from the vertebra vertebra /ver·te·bra/ (ver´te-brah) pl. ver´tebrae [L.] any of the 33 bones of the vertebral (spinal) column, comprising 7 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 4 coccygeal vertebrae . of an enormous sauropod dinosaur Noun 1. sauropod dinosaur - very large herbivorous dinosaur of the Jurassic and Cretaceous having a small head a long neck and tail and five-toed limbs; largest known land animal
sauropod -- with an estimated length of 160 feet -- excavated in central New Mexico The center of the U.S. state New Mexico. In the center of this region is Albuquerque, the largest city and only metropolitan area. External links
reptile genus - a genus of reptiles
family Titanosauridae, Titanosauridae - herbivorous dinosaurs of the Cretaceous , or "earth shaker," lived in the late Jurassic period, making these by far the oldest known proteins, says Spall, who described his team's work at a Geological Society of America The Geological Society of America (or GSA) is a nonprofit organization dedicated to the advancement of the geosciences. The society was founded in New York in 1888 by James Hall, James D. meeting in Albuquerque.
Other researchers argue that the proteins may hail from much more recent times. "Perhaps [Spall and his co-workers] have proteins there, but there are proteins everywhere. They are easy to contaminate con·tam·i·nate
1. To make impure or unclean by contact or mixture.
2. To expose to or permeate with radioactivity.
con·tam·i·nant n. . You have them in your thumbprints and they exist in ground-water, wherever organisms can exist," says P. Edgar Hare, a geochemist with the Carnegie Institute of Washington (D.C.)
The Los Alamos team drilled a core out of the huge vertebra and used solvents to strip away the mineralized min·er·al·ize
v. min·er·al·ized, min·er·al·iz·ing, min·er·al·iz·es
1. To convert to a mineral substance; petrify.
2. To transform a metal into a mineral by oxidation.
3. portion. High-pressure liquid chromatography revealed two or perhaps three proteins within the sample, they report.
The researchers did not extract enough material to identify the proteins they found, but they say their analysis of the amino acids in the molecules indicates the proteins are not collagen, the most abundant protein in bone.
Chemists have long wondered whether fossils might contain ancient biological molecules, but only recently have they developed sophisticated techniques that can analyze the very small samples extracted from bone. While researchers have identified free amino acids in animal fossils dating back several hundred million years, Spall says most investigators assume that proteins -- cannot remain intact for many millions of years.
At the outset, he says, "I didn't think we'd find anything." but the bones appeared exceptionally well preserved, perhaps explaining why the proteins survived. He and his colleagues have collected more seismosaurus bone samples, hoping to sequence and identify the proteins. They also plan to perform an amino acid analysis that can reveal whether the proteins are truly ancient.
Spall says their techniques for sampling and analysis avoid obvious contamination from human contact, but he adds that protein from groundwater may have seeped in while the fossil lay encased en·case
tr.v. en·cased, en·cas·ing, en·cas·es
To enclose in or as if in a case.
en·casement n. in sandstone for 150 million years. If so, he says, the isolated proteins would not belong to the dinosaur.
Stephen A. Macko, a geochemist at the University of Virginia in Charlottesville, raises another potential problem. He suggests that the material extracted by Spall might not be protein at all, but rather a nonbiological molecule that contains amino acids. "Further characterization of the material by other techniques should be in order before calling it a protein," says Macko, who recently helped isolate potential protein remnants from 66-milion-year-old dinosaurs.
The oldest proteins generally accepted by scientists date back only 1 or 2 million years, Hare says. But if investigators can isolate proteins belonging to much more ancient animals, they can use amino acid sequences to reinterpret re·in·ter·pret
tr.v. re·in·ter·pret·ed, re·in·ter·pret·ing, re·in·ter·prets
To interpret again or anew.
re relationships among species. For instance, scientists might compare bone proteins from dinosaurs, birds and reptiles to determine how closely these groups cluster on the tree of life. "Using a biochemical point of view to look at how organisms evolved would be a very powerfl approach for interpreting the fossil record," Macko says.