Radio Review: Inside Science - Ancient DNA and Human Evolution

The programme starts with a bold statement: 'No other field of science has experienced such an upheaval in the last few years as human evolution.' There is a reason for it: the recent addition of DNA research to the toolbox of techniques available to evolutionary scientists has led to remarkable findings.

In this programme, Dr Adam Rutherford gives a snapshot of the current state of the field of human evolution and, in particular, how genetic analyses helped to uncover previously unknown aspects of the history of our species and our near relatives. My concerns that my very limited knowledge of this field would prevent me from fully appreciating the significance of this recent 'revolution'  were unfounded; the programme was very good at highlighting the importance and scope of changes that genetics have brought to evolutionary study.

Most of what we know about our evolutionary ancestry has come from archaeological finds and the various methods for dating their age. Now, with DNA analysis, scientists have access to extra information about when and how different hominin groups lived and interacted together. This new biological evidence has changed the way we think about our evolutionary past. 

The programme was recorded mainly at a scientific meeting marking the 20th anniversary of the first successful attempt to analyse the DNA from Neanderthal bones in 1997. Technical advances had made it conceivable to study the genes of extinct species. The Neanderthal genome was fully sequenced only eight years after the human genome, allowing scientists to compare the two and investigate any biological changes that happened before and after divergence from our last common ancestor.

Although the new technology is truly extraordinary and has led to fascinating advances, Dr Rutherford is careful to give due credit to, as he calls them, the 'good old-fashioned' palaeoanthropology and archaeology. Without these, we would not be able to provide the context in which the genetic story can be embedded.

Nowadays, a lot of us still carry some Neanderthal DNA: around 1 to 2 percent of our genes have that origin. The genetic overlap is a result of 'gene flow events' between early humans and Neanderthals, which is a technical term, 'but you all know what that means', jokes Dr Rutherford. Interbreeding might have provided a quicker way of adapting to a new environment, bypassing the slow process of selection.

Rutherford is particularly skilful at pacing the material and directing attention to the main message. The programme delves into complex findings related to the movement and interaction between different hominin species. The picture painted by this new evidence is convoluted, however, the main point of the discussion is frequently reiterated and clarified, making it digestible.

New genetic evidence suggests that a type of archaic human must have interacted with the early Neanderthals at some point between the time when we first split from a common ancestor around 700,000 years ago, and the time the two species met again around 40,000 years ago when humans left Africa. Interestingly, there are no fossils to support this, and the new theory stemmed from the genetic material of early Neanderthals found recently in Atapuerca, Spain.

Overall, the show is very informative and pleasant to listen to. Dr Rutherford's genuine enthusiasm makes it easy to get excited about the new technologies and discoveries, even with relatively little prior knowledge. The show caters to anyone with a broad interest in science and general curiosity to find out more about new and exciting scientific discoveries. It provides enough information to get a good idea of the state of the current knowledge on this topic without getting bogged down in too much detail.

I wished the programme went deeper into the implications of the new findings. It briefly touches on some of them, for instance, that the gene flow events in Spain could explain the almost simultaneous spread of a type of stone tools observed in Europe and Africa. It could have benefitted from more such explanations of what the new discoveries have changed in our understanding of prehistoric technology and culture.

Even so, I found out a lot in such a short time. The host skilfully led the discussion towards most interesting points and makes sure that the main take-home message is clear and simple. I really enjoyed his appreciation of all disciplines and how they collectively enable us to see the big picture. With the exciting new technologies, it would be easy to dismiss the 'old-fashioned' methods; on the contrary, Dr Rutherford always gives credit to the fields of study that made these newest developments possible.

The list of programmes by Inside Science is long, and their subjects are broad and very topical; I will definitely be listening to another one soon.