All  
Neanderthal vs Human skeletons

Neanderthals and Humans are 99.84 percent genetically identical – so where are the differences?

Print

Research has shown that modern-day humans and their extinct Neanderthal cousins differ by only a fraction of a percent.  So what accounts for the differences that are known to exist between the two? In a ground-breaking new study published online in Science, scientists have discovered the cellular equivalent of on / off switches that determine which genes are activated or not.

Scientists have found that the genomes of Homo sapiens and Neanderthals are 99.84 percent genetically identical, and have fewer than 100 proteins that differ in their amino acid sequence. However, although numerous recent studies have shown that we are a lot more similar to Neanderthals than previously believed, there are still fundamental differences.  For example, Neanderthals had shorter legs and arms, bowlegs, larger hands and fingers, curved arm bones, and more prominent brows. There are also a number of diseases and neurological conditions that have been found in humans but not Neanderthals.  Could all these differences really be contained within a 0.12 percent difference?

Computational biologists Liran Carmel and stem cell biologist Eran Meshorer, at the Hebrew University of Jerusalem, and their team sought to answer this question by examining differences in the epigenomes of humans and Neanderthals, as well as the ancient hominid species known as the Denisovans. The genome is the sequence of 3 billion molecules that constitute all of a person's DNA while the epigenome is which bits of DNA are turned on or off even as the molecular sequence remains unchanged. For example, it is the epigenome that can account for difference traits between identical twins.

Their results revealed around 2,200 regions that were activated in today's humans, but silenced in either or both ancient species, or vice versa. When a gene is silenced, it does not produce the trait it otherwise would. In other words, differences between the species could be accounted for by on / off patterns in the DNA.

One of the major epigenetic differences was related to those that influence the shape and size of limbs. There were also significant differences in the on / off patterns between Neanderthals, Denisovans, and modern humans associated with neurological and psychiatric disorders including autism, schizophrenia and Alzheimer's disease. More of the Neanderthal and Denisovan versions were silenced, while the human versions were active.

However, the scientists acknowledged that the research technique is not without its limitations. Each individual’s epigenome can vary markedly from another’s due to diet, environment, and other factors. It is therefore impossible to know whether the on/off patterns found in Neanderthal genes are typical of the species overall or peculiar to the individual studied. Furthermore, epigenomes can vary between different tissues of the body, so epigenomes gathered from bone, hair, or teeth, will not necessarily say anything about the brain.

Nevertheless, the new method employed in this study is a first step towards further understanding the differences between modern-day humans and our ancient ancestors. As techniques and methods develop, there is promise that we may one day hold all the answers.

Featured image: Comparison of Neanderthal and Modern Human skeletons. Credit: K. Mowbray, Reconstruction: G. Sawyer and B. Maley, Copyright: Ian Tattersall

By April Holloway

Comments

aprilholloway's picture

Hello Guillaume, 

I don't quite follow the dwarf analogy, or see how it relates to the existence of Neanderthals. 

You are welcome to believe or disbelieve what you wish of course, but there really is a lot of evidence for the existence of Neanderthals. Only about 50 fossilized remains of a Tyrannosaurus Rex have been found, but we know they existed as a species from their form, their bones, and other traces.  

If you found 500 skeletons that have the same features as each other but have distinct characteristics from modern humans, what conclusion would you make?  

The fact is that the entire Neanderthal genome has been mapped, and comparisons have been made with humans down to the smallest detail. 

Considering scientists are able to extract DNA from an animal and create a living, breathing, identical cloned copy of it, suggests they have more than an inkling about what it is and how it works.  Whether it is 'black magic' is another issue altogether. I certainly have my reservations about the interference of science in natural processes. But evolution is not something to believe or disbelieve as it is not a religion or based on faith. The evidence speaks for itself. 

April

What you refer to as a "mutation" is simply epigenetics. Pay attention ...

Tsurugi's picture

That's adaptation, not evolution.

Evolution suggests adaptation leads to speciation over great periods of time, a process that is purely hypothetical because it has never been observed, for reasons that should be obvious, and because evidence of transitional species of any kind are so few and far between that they may as well not exist at all, because they should be everywhere...if speciation were true.

So despite the claims of evolutionary theory, adaptation does not infer speciation...which means adaptation is not necessarily evidence of evolution.

Evolution exists and can be seen on an almost daily basis in labs across the world.

Bacteria growing happily on an agar plate, they are then transferred to one containing an antibiotic, almost all die, some have a mutation in their DNA that means the antibiotic is not effective, they multiply and soon the plate is covered in bacteria, all of which contain the mutant gene conferring resistance to the antibiotic.

Evolution.

April

I again refer to my dwarf analogy and say that 500 skeletons do not make up an entire species which covered Europe and now I understand America, especially when the dwarfs lived so long ago that the skeletons have decomposed to the point where there are just a few left. I just cannot make a science out of this and I don’t think anybody else can for that matter.

If I went on a quest to find a species of human like people which are dwarfs and they lived some time ago I would probably find them in an un-decomposed skeletal form of about 500.

I am not sure if I believe in DNA science after all for most of out here, it has to be a belief system as we do not have even an inkling of what the black magic art of DNA is all about and further I suspect the science of genomes.

In my world ‘science’ is just not that. It is based mainly on a hypothesis that has been rushed to the mainstream press and swooped up by the masses as the truth when it is not. I am also very suspect of a group of people who’s income is reliant on scientific research and coming up with conclusions.
Why can we not accept that to some studies there are no conclusive
conclusions as with the Neanderthal.

I do not believe in the science of Evolution however I am also not a religious nut who says that God made me. I am still after many years on this plane of existence still trying to work out if God made me and I don’t have any answers of which I can cuddle as my favourite topic of imposing my will upon others, discussion.

Pages

Next article