I know that my blog usually focuses on the endangerment and conservation of animals. However, I think that the debate of brining back extinct species is a highly interesting and controversial one. A few weeks ago I wrote a post entitled ‘Should we bring extinct species back to life?’, which dealt with the possibility of de-extinction, and the consequences of resurrecting certain species. This post is my follow up piece to it, which looks at scientists seeking to clone the ancient hominid species, the Neanderthal.
At the moment, the Neaderthal genome is sitting as an abstract sting of billions of DNA letters in computer databases. Scientists could possibly use this genetic blueprint to recreate a Neanderthal in the flesh. In a relatively near future, developments in genetic engineering may just enable this advancement. However, the major question is whether this resurrection should take place.
Since the world’s first cloned mammal (Dolly the sheep) in 1996, scientists have greatly improved and expanded cloning techniques. In 2003, researchers brought an extinct species back to life – the bucardo, a type of wild mountain goat, however, the clone did not live longer than 10 minutes.
The process of cloning relies on a technique called nuclear transfer, which must start with an intact cell (either fresh or frozen) of that animal that would be possibly cloned. There are, however, no intact Neanderthal cells. In order to decode the Neanderthal genome, scientists had to piece many DNA fragments together, which were painstakingly extracted from 40 000 year old bones. We still, however, do not know if cloning would actually be possible.
George Church, a Harvard geneticist, has proposed an alternative approach for cloning extinct animals where their genome has been sequenced. It must start with a healthy cell of a species that is closely related. Cloning a Neanderthal could possibly start with a stem cell from a modern human. Through genetic engineering, scientists could make adjustments to a human cell’s DNA, so that it would match the code of the Neanderthal.
This is far from an easy task. In the genome, there are millions of spots that are different between Neanderthals and modern humans. Church describes a new technique called CRISPR which allows multiple sites to be edited in the genome at the same time. This is a major step forward for genome engineering of mammalian cells.
Although the techniques are still too unsophisticated and expensive to actually recreate the Neanderthal genome, the idea could still be plausible.
If a human cell could actually be turned into a Neanderthal cell, it would then have to be implanted into a surrogate mother’s womb – either a chimp or a woman, which would then develop into a fetus. This too would be a very challenging step, and it is known from previous cloning experiences to have a very high failure rate. For example, with regard to the cloning of the bucardo: scientists created 439 eggs of the bucardo’s nuclei, whilst only 57 developed into embryos, 5 survived the full pregnancy term, but only one was born. This failure rate could have a heavy physical, and emotional, toll on human surrogates.
Even if the clone did indeed survive, there are heavy and complicated issues of raising a Neanderthal. Neanderthals were similar to humans in some ways; they created art, used tools and seemed likely to have the mental capacity for abstract thinking and language. However, they were also very different. They were extinct before the agricultural revolution, making it very unlikely for them to easily stomach our modern diets – heavy in diary and grains. Their physical appearance is also very different: they were robust, short and stocky, with strong muscles and big heads. A Neanderthal child could be far stronger than modern people, as well as being intellectually disabled. Church points out that these ethical issues are crucial when considering any cloning project.
Some scientists are wondering and arguing if there is any valid scientific reason to bring this species back. The environment and development, as well as the educational environment and cognitive stimuli surrounding anyone born now days would be completely different from one born into a Paleolithic environment. Instead of bringing back a complete Neanderthal, some argue that it would be more useful and ethically correct to focus on creating only a few of its cells. This could uncover biological differences between modern humans and Neanderthals, and allow anthropologists an improved understanding in the two species’ divergent evolutionary histories.
Neanderthal bones were found in a Croatian cave with pieces of viable genetic material – in 2010 these bones were scoured and scientists released the first draft of the neanderthal genome. It revealed, among other things, that Neanderthals had actually interbred with ancestors of the modern humans. This information rocked the field of anthropology. It is very plausible that the Neanderthal biology could actually show us something about the issues and diseases that humans are facing now. Knowledge of the evolutionary process could possibly guide us towards possible treatments. You could possibly take a human immune cell, and alter it to be more Neanderthal-like, and see whether it would have the same kind of capacity in responding to pathogens. For example, modern humans carry genetic mutations that are linked to celiac and autoimmune diseases, which Neanderthals did not carry.Neanderthals had strong muscles and dense bones; adjusting the human biology to make it more Neanderthal-like may be able to treat muscle wasting and osteoporosis. Comparing human and Neanderthal cells could even assist researchers in fighting modern ailments.
However, for the time being, the technology for researching the Neanderthal biology remains far our of reach. Although, it could only be a matter of time…