Descubierta una nueva especie fósil humana en una cueva de Siberia

Compartió el planeta con los 'sapiens', los neandertales y los 'floresiensis'

El descubrimiento se ha logrado gracias a la secuenciación de su ADN

Rosa M. Tristán, Madrid

23.12.2010

Un equipo científico internacional, liderado por el Instituto Max Planck de Alemania, ha descubierto en Siberia los restos de una nueva especie humana que no se conocía hasta ahora, y que compartió el planeta hace unos 30.000 años con los neandertales, los 'sapiens' modernos y los 'Homo floresiensis' de Indonesia.

.

El nuevo linaje, bautizado como los denisovanos, porque sus restos se encontraron en la cueva siberiana de Denisova, es el primero descrito gracias a una investigación genética: en concreto, la secuencuación de ADN nuclear de la falange de un dedo de una hembra infantil de esta nueva especie.

.

Tras comparar su genoma con el de los neandertales (que se conoció este año) y el de 'Homo sapiens' actuales de Europa, África y Asia, se comprobó que los denisovanos no eran ninguna especie conocida, aunque parte de su ADN (menos del 3%) está presente en las poblaciones de Melanesia.

.

La paleogenética ha revelado, según se publica en la revista Nature esta semana, que estos homínidos son más parecidos a los neandertales que a nosotros, lo que significa que descienden de la misma población ancestral, que se dividió en estas dos ramas hace unos 600.000 años. Antes de ello, hace unos 800.000 años, su rama común se habría separado de la que dió origen a nuestra especie.

.

Un dedo y un diente

Una muela, localizada en la misma cueva, confirmaría también que su morfología es mucho más primitiva que la nuestra. Se parece a la dentadura que tuvieron los 'Homo erectus', otros homínidos del intricado árbol evolutivo humano de hace 1,8 millones de años.

.

«Todo parace indicar que los denisovanos se dispersaron ampliamente en el pasado», argumentó el jefe del equipo científico, Svante Pääbo, en referencia a los 7.000 kilómetros que separan la región rusa de Siberia de la isla de Nueva Guinea, en Oceanía.

.

Mientras estos homínidos se extendían por Asia, los neandertales lo hicieron por Eurasia durante cientos de miles de años, hasta que los 'sapiens' abandonaron África, momento en el que también se cruzaron, dejando su marca de ADN en todos los humanos actuales no africanos.

.

«Como se ve, la historia es mucho más compleja de lo que se pensaba. Ya no se trata de una clara historia de humanos saliendo de África y reemplazando a los neandertales. Ahora vemos que hay linajes entrelazados con más jugadores y más interacciones de las que conocíamos», apunta Richard Green, de la Universidad de California, otros de los firmantes del artículo.

.

De momento, y a falta de más fósiles en los que fundamentar el hallazgo (sólo hay un fragmento de dedo y un diente), los descubridores de este nuevo homínido han preferido no denominarle como una nueva especie.

.

La opinión de los expertos

La mayoría de los expertos en Paleontología preguntados por ELMUNDO.es consideran este trabajo «de un gran interés científico».

.

Para Manuel Domínguez Rodrigo, que excava en la Garganta de Olduvai (Tanzania), «muestra que en el Pleistoceno medio las poblaciones humanas euroasiáticas no establecieron barreras reproductivas entre ellas y abre el misterio de cómo unos homínidos en las estribaciones occidentales de Siberia pudieron haberse mezclado con los ancestros de una población geográficamente tan distante como la Melanesia actual».

.

Antonio Rosas, experto en neandertales del Museo Nacional de Ciencias Naturales, cree que planteará «la reconsideración de lo que es un ser humano porque la condición humana es un laberinto cada vez más complejo». «Debemos acostumbrarnos a que hubo un gran diversidad de especies humanas en un periodo muy reciente», afirma el paleontólogo.

.

Juan Luis Arsuaga, codirector en Atapuerca, cree que habrá que esperar para confirmar si los denisovanos son una nueva especie «porque con una molécula no se puede saber» y apunta que algunos fósiles hallados en China, que no eran ni 'Homo erectus' ni 'Homo sapiens', «igual tienen que ver con estos homínidos primitivos».

www.elmondo.es

Claude Lévi-Strauss

by Patrick Wilcken – review

David Lan *
04.12.2010

It had been pouring with rain. The hard, red soil of the Zambezi valley had turned to mud. All around me people were hurrying to their fields, taking advantage of this deluge to cut trenches with their hoes to prepare for the sowing of next season's crop. And suddenly I understood everything that had been puzzling me about the origin myth of these people among whom, as a student anthropologist, I'd been doing fieldwork for the past year
.
The mythological "first man" was said to have come from the south, from where that day's rain clouds were also riding. His name was Mutota, which means "the wet one". The contradiction I had to account for was this: when local people answer the question "who brings the rain?", they always say that it's under the control of the ancestral spirits of the people who lived in this territory before Mutota, their ancestor, arrived and conquered it. And yet, at the same time, it's an uncontested fact that "Mutota brings the rain".
.
If you're not tantalised by this paradox, Patrick Wilcken's biography of Claude Lévi-Strauss – the first in English – is probably not for you. But for me, and for thousands of students of social anthropology in the 1970s and 80s, Strauss, Lévi and Claude were the most intoxicating words in any language.
.
And this despite the fact that very few of us, I'd bet, actually read his books. We whizzed through introductions and maybe an early chapter or two, but his major works – the four-volume Mythologiques and The Elementary Structures of Kinship – are not for the faint-hearted.
.
Yet he was telling us something important: that all societies are as complex, as sophisticated, as rule-bound and as interesting as our own. The conventional comparative indicators of success were (are) wealth accumulation and levels of technology. Lévi-Strauss cracked open the seemingly secondary worlds of marriage, mythology, linguistics and social and existential identity, showing how each is an intricate system of exchange between individuals and between groups – and that the same sorts of systems operate in the Ardèche as in the Amazon.
.
Lévi-Strauss's credo is related by Wilcken thus: "Working their own systems, many cultures had succeeded where the west had failed. Inuits and the Bedouin had excelled at life in inhospitable climates; other cultures were thousands of years ahead of the west in terms of integrating the physical and the mental with yoga and Chinese 'breathe-techniques'. Australian Aborigines, traditionally seen as at the bottom of the evolutionary ladder, had one of the most sophisticated kinship systems in existence."
.
The methodology Lévi-Strauss fashioned to allow him to display these hidden complexities was structuralism – for decades the most resonant word across the humanities, its imprecision a part of its power. Its premise is that nothing can be understood in itself but only in relation to other, similar things – and, further, that this relationship can only be understood in terms of the relationships these other things have with yet other, similar things.
.
The questions that follow are: in each case, in what does this "similarity" lie, and from what perspective do these "similarities" appear? For Lévi-Strauss, all apparent reality is a map to be deciphered, revealing the map of a reality below which in turn leads to the map of the surface below that, and so on. But at the lowest point – what? Is there a lowest point? Or does it just keep going round and round?
.
From his middle years, Lévi-Strauss was the most famous academic in the world. He had his picture on the cover of Time magazine. His more tactfully written books, such as The Savage Mind and, especially, his marvellously affecting Amazon memoir Tristes Tropiques, sold widely and were, I'm sure, read with pleasure, if not always from cover to cover. His only rival as a public intellectual in France was Jean-Paul Sartre, with whom he fell out on the question unanswered above: what's underneath? What's the driving force? Sartre said: "History". Lévi-Strauss told the Washington Post: "The Sartre disciples said that nothing can be known without history: I had to dissent. But it is not that I don't believe in history. I just feel that there is no privilege for it."
.
And that did for him. As Tony Judt puts it in Postwar: "As an interpretation of human experience, any theory dependent on an arrangement of structures from which human choice has been eliminated was hobbled by its own assumptions. Intellectually subversive, structuralism was politically passive." The structuralist ship had extremely wide sails – but in the end, the wind went out of them.
.
The Poet in the Laboratory doesn't quite catch the fireworks that had me and my best undergraduate friend weekend after weekend tearing Andean kinship systems apart, desperate to find out exactly why the father's sister's daughter couldn't marry the mother's brother's son, or whoever. But it lays out the life with clarity, efficiency, readability and occasionally dissent – from the youth's first liaison with his three "mistresses", Freud, Marx and geology, to the hyper-distinguished old fellow tottering into the Académie Française, the first of his tribe to be let in. A superbly thrilling life it was – and one well worth reliving at second hand.
Claude Levi Strauss: The Poet in the Laboratory
by Patrick Wilcken

* David Lan is artistic director of the Young Vic Theatre and author of Guns and Rain: Guerrillas and Spirit Mediums in Zimbabwe.
www.guardian.uk/