Forensic Stories, Medico-legal context and Life


Modern humans emerged far earlier than previously thought
November 7, 2011, 11:29 pm
Filed under: Bones, DNA, Forensics, Genes | Tags: , , , , ,

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.

via Modern humans emerged far earlier than previously thought.

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What shapes a bone?
November 7, 2011, 11:27 pm
Filed under: Bones, DNA, Forensics, Genes | Tags: , , , , ,

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?.



Continents influenced human migration, spread of technology
November 7, 2011, 11:26 pm
Filed under: DNA, Genes | Tags: , , ,

Continents influenced human migration, spread of technology.



The Foramen Magnum and Neurodegenerative Diseaes
November 7, 2011, 11:23 pm
Filed under: Bones, Foramen magnum, Forensics | Tags: ,

The Foramen Magnum and Neurodegenerative Diseaes.

 

foramen magnum

Foramen magnum in Latin means great hole. It is the largest of several openings called foramen or canals in the base of the skull to allow for the passage of nerves, blood vessels, cerebrospinal fluid and connective tissue into and out of the brain. It is located in the anterior portion (front) of the occipital bone. The picture above shows the skull base looking down into it, the front of the skull is at the top and the foramen magnum is the largest opening and is not labeled.