The world was stunned a decade ago when a group of scientists and researchers announced that the humble chicken was the closest living relative of the fearsome Tyrannosaurus rex, paving the way for possible biological investigations of extinct animals.
In 2007, the group led by John Asara of the Harvard Medical School extracted and examined collagen protein from the preserved soft issue of a 68 million-year-old female T. Rex’s fractured thighbone unearthed from a soggy marsh in Montana in 2003 and found out that it was similar to that of the chicken.
Using the analytical technique called mass spectrometry, the group sequenced six collagen peptides or protein fragments from the T.rex’s leg bone and found out that five of the sequences were similar to chicken proteins.
However, the findings were met with skepticism and opposition from fellow scientists.
Among them was the group of Michael Buckley of the University of Manchester’s School of Earth and Environmental Sciences, which claimed in 2008 that the T.rex-chicken link was nearer to fiction than to fact.
The group said it had reinterpreted the data used by Asara and found out that the T. rex “does not group” with either birds or reptiles.
“We require more data to be convinced of the authenticity of the T. rex collagen sequences reported by Asara et al,” said Buckley’s group.
Asara’s group countered Buckley’s assertion through a March 2008 technical comment, saying that, “Buckley et al. reinterpret and misinterpret our data and question sequence authenticity, but they used a suboptimal phylogenetic algorithm to analyze only a subset of reported sequences and they suggest analyses that are less sensitive and less specific than mass spectrometry.”
Also, Asara’s group responded to Buckley’s doubt on the survival of collagen protein in the T. rex specimen, saying the dinosaur’s burial under approximately 1,000 meters of semi-consolidated sandstone “limited its exposure to modern environmental influences” such as water, light, and air “contributing to the retention of endogenous protein…”
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‘It’s like the monkey that correctly typed 7 out of 100,000 words’
But the rejection of Asara’s findings did not stop.
In July 2008, a group led by Thomas G. Kaye of the Arizona-based Foundation for Scientific Advancement, said that based on its investigation, the soft tissue in the T. rex’s preserved bone supposedly containing protein was in fact a “bacterial biofilm that mimics soft structures previously thought to be biological tissue,”
Kaye said the biofilm was similar to the formation of calculus or hardened plaque in human teeth.
A third critic, Pavel A. Pevzner, director of the National Institutes of Health Center for Computational Mass Spectrometry at University of California, also said the probability of the T. rex-chicken link was “rather low” because of the statistical insignificance of the number of collagen peptides that Asara’s group generated from the dinosaur’s fossilized bone.
Pevzner pointed out in his August 2008 paper that only seven peptides (only six, in fact, as later admitted by Asara) were extracted and “did not reveal all generated spectra and never specified exactly how many spectra were generated.”
He compared Asara’s work to that of a boy who watched a monkey typing random keys on a typewriter and discovered that out of 100,000 words, the primate was able to spell seven of these correctly.
“The boy is so surprised that he writes a paper called ‘My monkey can spell!’ and publishes it in a scientific journal,” said Pevzner.
Scientist says iron preserved protein in T. rex’s body
In 2013, during a LiveScience interview, Mary Schweitzer, a molecular paleontologist at the North Carolina State University, defended the survival of protein in the soft tissue of the remains of the 68 million-year-old T. rex, which was earlier questioned by Kaye’s group.
She said the presence of iron in the dinosaur’s body, which included a 107-centimeter-long femur bone, was able to preserve the tissue that was “still soft and still transparent and still flexible” when Schweitzer’s group found it in 2005 and later sent it to Asara for analysis.
According to Schweitzer, iron generates free radicals that “cause proteins and cell membranes to tie in knots.”
“They basically act like formaldehyde,” she added.
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