Scientists from the University of Montana say that they managed to extract blood remains from the bones of a Tyrannosaurus rex that died about 65 million years ago
Scientists from the University of Montana say they managed to extract blood remains from the bones of a dinosaur that died about 65 million years ago. This is the first time this has been done. In this way, science is approaching - to an extent that it has never been before - the fantasy of science fiction about the re-creation of creatures that once lived, using the genetic information found in their blood cells. Unlike most fossils found so far, the dinosaur skeleton, a nearly complete Tyrannosaurus rex found in eastern Montana, was buried in conditions that prevented its bones from breaking down into minerals, thus preserving the interior of the bone in its original state.
Because of the good condition in which the bones were kept, Dr. Mary H. Schweitzer, a paleontologist at the University of Montana, to look for direct signs of life, such as cells, DNA and proteins.
The practice of extracting ancient molecules is a fascinating but extremely treacherous field, and many scientists have stumbled into it. The more sensitive the extraction technique, the greater the chance of "exiling" molecules that contaminated the source. For example, the claim by a team of researchers from Utah that they succeeded in extracting DNA from the bones of an 80-million-year-old dinosaur was later refuted by other researchers, who claimed that it was a human genetic code. Due to concerns of this type, Dr. Schweitzer and her colleagues acted cautiously and waited several years before publishing their findings. Dr. Schweitzer emphasized that she was unable to find any direct evidence of the presence of cells, but a chemical used to detect DNA was able to pick up something in the holes where the blood cells were supposed to be. According to her, she was unable to find DNA that could be clearly identified as belonging to a dinosaur. However, she and her colleagues were more successful in searching for recycled mutin - the part of hemoglobin that serves as the oxygen carrier in the blood. In the June issue of the journal Academy of Science The Proceedings of the National, they report that they were able to find evidence of the presence of hematin in six separate chemical tests. In one of the experiments, they injected crushed dinosaur bone into mice in an attempt to see if they would develop a vaccine against the blood of the dinosaur. Since they could not get a dinosaur to take his blood, the scientists chose a substitute in the form of a turkey. The choice was based on the theory that the origin of birds is from the dinosaurs and therefore the turkey is a distant relative of the Tyrannosaurus rex. The mice did react to the blood, evidence that they had developed genes for some part of the hemoglobin molecule.
According to Dr. Schweitzer, the immune system of the mice apparently reacted to a small part of the hemoglobin molecule and not to all of it. Another chemical test raised the possibility that the condensed hemotin is attached to a protein particle.
Dr. S. Blair Hedges, an evolutionary biologist at Pennsylvania State University, says that Dr. Schweitzer's paper convinced him, since he himself was able to collect "a fairly significant body of evidence supporting the possibility of the preservation of biological molecules in dinosaur bones."
Dr. Norman R. Pace, a member of the National Academy of Sciences, who recommended the publication of Dr. Schweitzer's article in the academy's journal, says that in his opinion "she did a very careful job, the best that can be done given the current technology." The importance of Schweitzer's work lies, apparently, in the message it conveys to other fossil researchers, according to which it makes sense to look for biological molecules in fossils, although this should be done with caution. Dr. Schweitzer believes that the fact that the dinosaur bones almost did not undergo a mineralization process is out of the ordinary, but not unique, and it is possible to find molecular evidence preserved in other fossils as well.
The importance of extracting DNA from fossils is that it may help reconstruct evolutionary development. Proteins, for example, may provide immunological information that can clarify the relationships between already extinct species.
Ha'aretz, 10/7/97 The Hidan website was until 2002 part of the IOL portal from the Ha'aretz group