DNA tells big story of T.rex’s link to chickens
Fri Apr 25, 12:19 PM ET
WASHINGTON (AFP) - It may seem unfathomable, but DNA testing has shown the towering Tyrannasaurus rex’s closest living animal relatives include the humble chicken, a new study has found. ...
Actually, this isn’t so unfathomable, evidence for this has been growing for years. E.g., the existence of feathered dinosaurs; or check the sample essay HERE.
Ira Flatow discussed these results with Associate Prof. Mary Higby Schweitzer of NC State University on last week’s Science Friday with Ira Flatow. Find it (and related links) HERE.
I love it when a plan comes together. First, science discovers morphological evidence. Now we get genetic evidence to support the morphology. Ain’t creationism grand?
I love it when a plan comes together. First, science discovers morphological evidence. Now we get genetic evidence to support the morphology. Ain’t creationism grand?
Actually, to be fair, the original article I quoted above seems to have gotten the facts wrong. It wasn’t genetic evidence (or evidence from DNA) but rather the evidence of links between certain sorts of protein in the collagen in bird and dinosaur bones. At least that’s how it sounds from the interview.
Update: on this week’s SGU podcast they mentioned a letter, apparently from Steven Salzberg, questioning the data behind the paper that started this thread. His claim is that the collagen in this experiment is not from T. Rex, but probably contaminant protein from (modern) bacteria.
See his letter HERE. He also mentions THIS technical comment from Science.
Clearly there should be room here for a response-to-the-response, and we’ll see where it all shakes out. But if Salzberg is right, this is a non-story.
What’s the unintentional version of the Piltdown Man? So much for KFT-Rex.
Seriously, I know there is some debate about whether birds and dinosaurs are related. It seems that in spite of some of the physical similarities, there are some problems with the timeline as it relates to the fossil record. I thought it was pretty well explained in this older article:
It’s not surprising that there are some holes given the length of time. The second article may help to explain some of the inconsistencies described in the first article. It wouldn’t surprise me to learn that birds came from dinosaurs but were already developing at the time dinsaurs went extinct. Perhaps their greater mobility allowed them to survive whatever events wiped out the dinosaurs. Perhaps it was more than just mobility, perhaps they were better evolved for climate change. Pure speculation on my part.
Just to be clear, Salzberg’s point does not in any way call into question the link between birds and dinosaurs. It simply calls into question this particular paper. The larger theory has a large amount of other data behind it.
Science Friday had a podcast interview with the author of the paper. I don’t know enough to evaluate the technical details, but she had a good point in that Salzburg’s attack on it was a bit vitriolic and not by itself evidence that his contention regarding her paper is true. As with all science, the true test will come with further research and the success or failure of others to replicate the original study. I often find the reciprocal letters to the editor in science journals interesting, but the real answer doesn’t usually settle out until much latter.
I wouldn’t disagree that there is probably a link, I was trying to use the first article mainly to show some of the discrepancies that exist in the fossil record. There does not seem to be a clear evolutionary line and there seems to be some debate about when birds began evolving from dinosaurs and finding the “missing link.”
I’m not an expert on this but my understanding is that one school of thought is that birds evolved from dinosaurs based on the parts of the fossil record and the Archaeopteryx, a dinosaur with wings, feathers, and many dinosaur features. http://en.wikipedia.org/wiki/Archaeopteryx
Those feathered dinosaurs found in China in 1998 (http://www.cnn.com/TECH/science/9806/23/feathered.dinosaur/) were in the early stages of aviary evolution and were probably flightless. They were also “younger” than Archaeopteryx which begs a few questions. Was Archaeopteryx a dead end, the neanderthal of birds? How broad was the aviary evolution and were there animals that developed some bird-like qualities and then continued to remain flightless? Were these Chinese dinosaurs the ostrichs of their days.
My understanding is that there is a debate about whether birds evolved from climbing trees and gliding or from running on the ground and then gliding.
Archaeopteryx are as old as 155 million years, whereas T-Rex existed as early as 60 million years ago. This begs the question, how could birds come from T-Rex if there were other more bird-like dinosaurs 80 million years earlier? Does this mean that T-Rex and birds are cousins rather than father-son so to speak. Until there is a clear evolutionary line there will continue to be debate about the origin of birds.
This sort of ties in (well, not really but kind of), I didn’t see it posted anywhere else here (sorry if it is!) but recently the platypus genome was sequenced and analyzed, confirming what many people had suspected, a jumble of reptilian and mammalian genes:
http://www.genome.gov/27026246
“The mix of reptilian, mammalian and unique characteristics of the platypus genome provides many clues to the function and evolution of all mammalian genomes,” said Richard K. Wilson, Ph.D., director of Washington University School of Medicine’s Genome Sequencing Center and the paper’s senior author. “Now, we’ll be able to pinpoint genes that have been conserved throughout evolution, as well as those that have been lost or gained.”
I had always thought of the platypus as a romantic encounter between a duck and a beaver gone horribly wrong. I didn’t know they had reptilian characteristics (other than the egg laying). I read somewhere that mammals don’t easily create hybrids (such as mules). I guess that is only over the short term.
Update: on this week’s SGU podcast they mentioned a letter, apparently from Steven Salzberg, questioning the data behind the paper that started this thread. His claim is that the collagen in this experiment is not from T. Rex, but probably contaminant protein from (modern) bacteria.
See his letter HERE. He also mentions THIS technical comment from Science.
Clearly there should be room here for a response-to-the-response, and we’ll see where it all shakes out. But if Salzberg is right, this is a non-story.
Yeah this was kind of confusing…
The same issue mentioned A recent genetic analysis shows that the duck-billed platypus shares some genetic features in common with birds rather than other mammals.
(see above)
http://www.theskepticsguide.org/skepticsguide/podcastinfo.asp?pid=146
Guess so! That’d be quite some KFC ...
