Even though trade in ivory has been banned, the poaching of tuskers continues unabated, threatening African elephants.However, Alfred Roca, assistant professor at the University of Illinois, has found a way to determine where the ivory comes from. He and his team have sampled elephants at 22 locations in 13 African countries to get sequences of their mitochondrial DNA mtDNA.mtDNA is the DNA located in mitochondria, structures within cells that convert the chemical energy from food into a form the cells can use. Most DNA is “nuclear”, found in the cell nucleus.What makes mtDNA a good marker for tracing the origin of ivory is first, that it is transmitted only by females and second, the fact that female elephants do not migrate between herds, the journal Evolutionary Applications reports.Roca and collaborators wanted to match these fragments to elephants from a specific location.
An international team of researchers based at the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing, including a physical anthropology professor at Washington University in St. Louis, has discovered well-dated human fossils in southern China that markedly change anthropologists perceptions of the emergence of modern humans in the eastern Old World.
The research was published Oct. 25 in the online early edition of the Proceedings of the National Academy of Sciences.
The discovery of early modern human fossil remains in the Zhirendong (Zhiren Cave) in south China that are at least 100,000 years old provides the earliest evidence for the emergence of modern humans in eastern Asia, at least 60,000 years older than the previously known modern humans in the region.
“These fossils are helping to redefine our perceptions of modern human emergence in eastern Eurasia, and across the Old World more generally,” says Eric Trinkaus, PhD, the Mary Tileston Hemenway Professor in Arts & Sciences and professor of physical anthropology.
The Zhirendong fossils have a mixture of modern and archaic features that contrasts with earlier modern humans in east Africa and southwest Asia, indicating some degree of human population continuity in Asia with the emergence of modern humans.
The Zhirendong humans indicate that the spread of modern human biology long preceded the cultural and technological innovations of the Upper Paleolithic and that early modern humans co-existed for many tens of millennia with late archaic humans further north and west across Eurasia.
Researchers at Johns Hopkins found that use over time and not just genetics informs the structure of jaw bones in human populations. The researchers say these findings may be used to predict the diet of an ancient population, even if little evidence exists in the fossil record. It can also make it easier for scientists to pinpoint the genetic relationship between fossils.
Their results were published online June 23 in the American Journal of Physical Anthropology.
“Our research aimed to see how much of the mandible’s—or jaw bone’s—shape is plastic, a response to environmental influences, such as diet, and how much is genetic. We used archaeological jaw bones from two different regions to answer that question,” explains Megan Holmes, graduate student at the Johns Hopkins Center for Functional Anatomy and Evolution, and lead author of the paper. “Before we can make inferences about what the shape of a bone tells us, like what environment the individual lived in, who it’s related to or what it ate, we have to understand what creates that shape. The idea that function influences the shape of jaw bones is great for the archeological record in terms of discovering the diet of a population, and it’s also really useful for reconstructing the fossil record—finding which fossils are related to which, and how.”
via What shapes a bone?.