Read the oldest hominid DNA - around 400 thousand. years! Missing ... - Gazeta Wyborcza

Homo heidelbergensis (Nature)

could be a common ancestor of the two species of humans – our modern and extinct Neanderthals. But the results of the analysis rather than scientists explain the riddle, but had made them uncomfortable.

Deep inside the cave system in the mountains of Atapuerca in northern Spain, 30 meters under the ground is the famous archaeological site called Sima de los Huesos – loosely translated “pile of bones”. At the bottom of the 12-foot-high limestone fault was discovered there in the 80s remains of at least 28 hominid. Until now it was thought that they belong to the species Homo heidelbergensis – rather poorly-understood, which gave rise to the Neanderthals in Europe and, as is believed to modern humans in Africa.

Neanderthal under construction

Bones complex “on the pile” are, according to recent analysis of 400 thousand. years. Times precede the appearance of the species Homo sapiens, which took place around 200 thousand. years ago. From the look more like the Neanderthal. Thus, many scholars expected the Spanish caves lie close to the DNA of the Neanderthal genome. The same authors study published this week in the weekly magazine “Nature” they said on the eye remains to look like “Neanderthal in construction”.

remained to be investigated, but that seemed difficult. So far, the old DNA for sequencing were recovered only from the remains of a hominid discovered with cold climates. In warm areas, such as in Spain, the genetic material breaks down fairly quickly.

However, Matthias Meyer (co-author of today’s work) encouraged by the success in reading counting a 300 thousand. mitochondrial genome of years the cave bear, which also came out of the cave Sima de los Huesos, he decided to try it.

Scholars nawiercili in three places one of the bone (femoral) collected the cave and mined it less than 2 g of material with which then isolated the DNA.

The work was very difficult, because the genetic material of a very polluted during the extraction and transport of bone. It was full of us modern DNA. However, advanced sequencing techniques have allowed to sift the wheat from the chaff. The end result of the work was almost complete mitochondrial genome of the ancient hominid.

Mitochondrial means that it was not a full genome (located in the nucleus of the cell), but derived from the mitochondria, or structures that are mini-power plants of our cells . They also contain their own DNA – but it is much less, and most importantly it comes only from the mother. Mitochondria therefore inherit only in the female line.

The sequenced DNA was then compared to the genetic material of modern humans, chimpanzees and bonobos, and Neanderthals and Denisovans.

The results were surprising. They suggest that the test hominid was most closely related to Denisovans, mysterious species known only from a single finger bone and two teeth discovered in a cave in Siberia.

What about this plant

– This job is like a dream come true – says David Reich of Harvard medical school in Boston. It is the culmination of previous discoveries, including the last, or read the oldest, so far, the DNA derived from ?yj?cego700 thousand. years ago, the ancestor of the horse.

– but not quite know what to think – says Meyer.

– I do not have any evidence discovered in Siberia that Denis ever inhabited the area near Atapuerca. This is the other end of the world. It does not make sense – agrees Chris Stringer, a paleoanthropologist at London’s Natural History Museum.

The biggest mystery is how and when our line of Homo sapiens split into Neanderthal and denisowia?sk?. Also unclear are the circumstances in which later split these last two groups.

– we know that both of these events occurred roughly at the same time when hominids from Sima de los Huesos lived in Spain – anthropologists say. – Not what I expected. Besides, no one saw it coming – says Chris Stringer.

So who were hominids with piles of bones?

mother had only sons

Researchers speculate that the Spanish hominid belonged to an unknown species before – probably the common ancestor of Neanderthals and Denisovans. Their descendants later colonized the east and evolved into Denisovans. – I think that is the most likely scenario – says Meyer. – We assumed that these are the direct ancestors of Neanderthals or Homo heidelbergensis. We were wrong – explains geneticist.

– This, however, does not explain why the bones from Sima de los Huesos are so similar to Neanderthal – Rebuttal Chris Stringer. In his opinion, this could be the ancestors of Neanderthals, who appeared after the separation of the lines Denisovans.

– Neanderthals could easily lose mitochondrial genes, which they shared with Denisovans, because the mini-power plants are transmitted only in the female line. They could therefore be lost if the woman had only sons. This is because in the mitochondrial genome of the Neanderthal no similarities to hominids from Sima de los Huesos – argues Stringer.

Meyer oversaw the work of the team Svante Paabo famous, a molecular geneticist with the Max Planck Institute in Leipzig, Germany (where it operates Meyer .)

– Reading this mitochondrial DNA raises more questions than it answers – worried Paabo. – These genes, however, only tell us the story of the mother of the individual, as well as her mother, grandmother, etc. Maybe a full and true picture is still hidden from us – he added.

The only way to discover the truth is to read the entire nuclear genome . Meyer is working on that. – It’s incredibly difficult, because nuclear DNA is badly damaged and fragmented – he explains.

It is, however, strive, because the result can be exciting. This form of hominids lived in an age when gave birth to the roots of Homo sapiens.

archaeological traces indicate that homonidy the Sima de los Huesos have already had many human characteristics in behavior. Continue to benefit from very simple stone tools, but probably already used early funerary practices. – Present the dead stone tools could be a kind gifts for the dead – says Stringer.

Some paleoanthropologists believe that the bodies of the dead hominids do not accidentally fall into the limestone gorges. Most of the skeletons belonged to adults or young males, many of the bones bore traces of deformities and diseases. At the site also found, inter alia, deformed skull of a 12-year-old girl, which suggests that the tribe took care of a defective child.

Scholars assume that the corpse was deposited on top of the shaft and gradually sliding off to him. If so, this is the earliest example of a special-purpose space for the dead.

Elsewhere in Atapuerca mountains, archaeologists also discovered the remains of an older man with a deformed spine. Such an individual is not able to feed itself and defend itself. A man’s age indicates that they had to look after him and protect him. – This “smells” a man – excite scholars.

confusing evolution

– Ability to penetrate in hominid genes from Sima is a great step in discovering our history. Read the full genome would be achievement not to be underestimated – says David Reich. – We could find out which of the genes of modern humans were already “in place” and that had to change, we can become the people – he added.

Svante Paabo notes that earlier reading of the full Neanderthal DNA and Denisov showed that they had a common ancestor that lived about 700 thousand. years ago. The remains from the Sima, in his opinion, just for such an ancestor belong.

geneticist hopes that the mystery will be revealed soon. – My goal was to explore the mysteries of our evolution, and not interlacement her even more – he explains.