Synchrotron Reveals How Neanderthal Teeth Grew
Scientists from the United Kingdom, France and Italy have studied teeth from Neanderthals (info) with X-rays from the European Synchrotron Radiation Facility (ESRF). They found that the dental development of Neanderthals is very similar to modern humans. Their results are published in the journal Nature this week.
Neanderthals first appeared in Europe approximately 200,000 years ago and became extinct about 25,000 years ago. These predecessors of modern humans have always been considered genetically closer to us than any other members of the genus Homo. It has even been suggested that Neanderthals achieved adulthood faster than modern humans do today.
A research team from the United Kingdom, France and Italy has recently shed new light on this theory by studying this species’ teeth. Teeth express genetic differences found between individuals and different populations more efficiently than any other tissues preserved in the fossil record. Studies with teeth can identify a timescale on the entire period of dental development that occurs from before birth until adulthood.
Continued at "Synchrotron Reveals How Neanderthal Teeth Grew"
Based on the Letter to Nature "How Neanderthal molar teeth grew" by Macchiarelli* et al.
Growth and development are both fundamental components of demographic structure and life history strategy. Together with information about developmental timing they ultimately contribute to a better understanding of Neanderthal extinction. Primate molar tooth development tracks the pace of life history evolution most closely and tooth histology reveals a record of birth as well as the timing of crown and root growth. High-resolution micro-computed tomography now allows us to image complex structures and uncover subtle differences in adult tooth morphology that are determined early in embryonic development. Here we show that the timing of molar crown and root completion in Neanderthals matches those known for modern humans but that a more complex enamel-dentine junction morphology and a late peak in root extension rate sets them apart. Previous predictions about Neanderthal growth, based only on anterior tooth surfaces were necessarily speculative. These data are the first on internal molar microstructure; they firmly place key Neanderthal life history variables within those known for modern humans.
*See the Nature interview "Roberto Macchiarelli: The whole tooth" (25 September 2003):
Roberto Macchiarelli is a palaeoanthropologist. Until recently at the National Museum of Prehistory and Ethnography in Rome, he is currently professor of human palaeontology at the University of Poitiers, France.
What was your first experiment as a child?
I grew a colony of bacteria. I remember my father's embarrassed expression as he asked fruitlessly for agar-agar in all the pharmacies of the district.
Whose graduate student would you most like to have been?
Albert Dahlberg at the anthropology department of the University of Chicago in the early 1970s.
What scientific paper changed your career path?
Loring Brace's papers on dental size reduction in hominid evolution... [More]
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