(+1) 647 931 2711A major breakthrough in the fundamental understanding of human origins on planet earth has just been realized using DNA testing. Hidden in a cave in the country which is now Spain a human bone was recovered and submitted for testing. Little did scientists know at the time but this bone would prove to be a game changer in the historic age of human existence on the planet. The testing revealed that this human specimen was at least 400,000 years old- quadrupling the previously oldest recorded specimen of human origin dated to 100,000 years in age.
Spanish thigh bone: who were they?
At this point there may be more questions than answers provided by the results of the early stage DNA testing. While the dating of any human specimen to this 400,000 year mark is substantial news, many scientists are raising more questions as to what they are looking at. As many people know, the human being has evolved over thousands of years and our ancestors come from distinct groups of early humans such as Denisovans and Neanderthals, each with their own particular region of origin.Preliminary testing has of the DNA from the cave has been performed on mitochondrial DNA. This type of testing is unique in that the genetic material is located outside the cell’s nucleus and is only passed from a mother to her offspring. By mapping this mitochondrial DNA in its completion, scientists expected to find Neanderthalic origins as the area which is now Spain was settled by these early humans historically. The evidence has now come into question as the testing instead revealed that the human origins are more closely related to the Denisovans, a group which previously has only been found in Siberia and Asia leading many scientists to ponder what in the world are they doing in the pit of a Spanish cave.
Cave of bones
As more focus has been brought to the specific location where these human bones were recovered, a previously unknown – at least outside the scientific community – cave in Spain is getting a lot of new attention. The cave is known locally as “Sima de los Huesos” is located in the Atapuerca Mountains and has long been a source for scientists to harvest human fossils that still contain genetic material. The “cave of bones” is actually more of a pit where for some reason unknown to modern-day scientists, bones were collected here for thousands of generations. The cave’s unique location and topography produce very dry air and cold air which has enabled the bones to be essentially “refrigerated” over time. This preservation of human samples has provided for a treasure trove of scientific information to be gleamed from the bones contained inside. Testing bones is often done during forensic DNA analysis. This is typically because bones are the only human tissue that can survive for such long periods and in adverse environmental conditions. Depending on the state of the samples, the type of sample (bones are just one of the many samples that can be tested for DNA), and the scope of the test, a different method of DNA analysis might be used. Why not click here for more information about the history of forensic analysis.
Error on the side of caution
Paleoanthropologist John Hawks, a scientist from the University of Wisconsin in the United States stresses that at this early stage in the discovery, the science community should be cautious in defining what these DNA tests mean. The controversy is mostly surrounding the use of the mitochondrial DNA which in similar cases has caused scientists to start making conclusions which were later found to be errant. Mitochondrial DNA as its past down from mother to offspring can provide many answers to the movements of early groups historically. It can also however leave out critical information such as ancient interspecies breeding. These exact scenarios have occurred in other groups such as polar bears which caused blended mitochondrial DNA samples. View more information about what mitochondrial DNA is and how testing is carried out.
For now the facts remain that the dating is accurate, however to which early human species they belong and the implications of that connection is information that can only be evaluated after further DNA testing.
