Humans share Neanderthal genes from interbreeding 50,000 to 100,000 years ago
Professor Svante Paabo, director of evolutionary genetics at the Max Planck Institute in Leipzig, Germany, is leading an international project studying 1.1 billion DNA fragments taken from Neanderthal bones. He reported in the journal Science last week that humans in Europe all have some ‘caveman biology’.
The four years of research involved making sense of fragmentary runs of DNA from Neanderthal bones. The scientists are convinced that early modern humans and Neanderthals interbred between 50,000 and 100,000 years ago. As a consequence, between 1 and 4 % of our DNA comes from this prehistoric source.
In the 7 May 2010 issue of Science, Green et al. report a draft sequence of the Neanderthal genome comprising over 3 billion nucleotides from three individuals, and compare it with the genomes of five modern humans from across the world. A companion paper by Burbano et al. describes a method for sequencing target regions of Neanderthal DNA. A News Focus, podcast segment, and a video commentary, text, and a timeline of Neanderthal-related discoveries provide additional context for their findings.
The scientists conclude that Human-Neanderthal relations occurred as the pioneering bands of Homo sapiens ventured out of Africa.
When they reached the Middle East and Near East they encountered groups of Neanderthals who had long before preceded them and had occupied Europe from the Atlantic to the Middle East. It is now deduced that some interbreeding resulted.
The discovery emerged from the first attempt to map the complete Neanderthal genetic code. It probably settles a long-standing academic debate over interbreeding between separate branches of the human family tree. Evidence in the past has pointed both ways, for and against modern humans and Neanderthals mixing their genes.
The Neanderthals, Homo neanderthalensis, were a parallel human species which parted evolutionary company from our direct ancestors between 270,000 and 440,000 years ago. Around 400,000 years ago early Neanderthals left Africa, where Homo erectus was still evolving and would lead by 200,000 - 180,000 years ago to Homo sapiens.
By 100,000 years ago Homo sapiens, having spread over Africa, were leaving northern Africa too.
The two populations coexisted in Europe and Western Asia, but with the numbers of Neanderthals continually falling until extinction around 28,000 years ago (probably because modern humans were brighter and more competitive).
“For the purpose of the analysis the researchers also sequenced five present-day human genomes of European, Asian and African origin and compared them with the Neanderthal data. To their surprise they found that the Neanderthal is slightly more closely related to modern humans from outside Africa than to Africans, suggesting some contribution of Neanderthal DNA to the genomes of present-day non-Africans. Interestingly, Neanderthals show the same relationship with all humans outside Africa, whether they are from Europe, East Asia or Melanesia.”
Svante Pääbo explains: “Neanderthals probably mixed with early modern humans before Homo sapiens split into different groups in Europe and Asia.” This could have occurred in the Middle East between 100,000 and 50,000 years ago before the human population spread to East Asia. It is known from archaeological findings in the Middle East that Neanderthals and modern humans overlapped in time in this region.” http://www.laboratoryequipment.com/News-humans-neanderthals-interbr...
The situation is unclear. The Neanderthals might have descended from heidelbergensis or antecessor or erectus.
I have been writing a book for some years, for which I had to summarise existing knowledge and from which I now take the following:
Homo georgicus 1.75
Homo ergaster 1.9 - 1.5
Homo erectus 1.8 - 0.05
Homo floresiensis 0.095 / 0.074 to 0.012
Homo antecessor 0.8
Homo heidelbergensis 0.7 - 0.2
Homo neanderthalensis 0.3 - 0.03 evolved parallel to Homo sapiens
Homo sapiens 0.2 to present
More information from researchers is needed to sort the probems out, but almost every year seems to bring advances to one part or other of this table.
Little off topic, but I've bred and raised dogs and most specific dog breeds do gravitate to their own breeds socially. Just like doves and pigeons will breed when given no other choice, they still prefer their own species.