Note in Science page
Created Apr 26 10, Updated Sep 15 12 00:40
Neanderthals may have interbred with humans go to comments

Earlier research suggested that there was no interbreeding between Humand and Neanderthals, but these early results were not based on an analysis of the complete Neanderthal genome… (now the first draft of the complete neanderthal genome is ready; will be final soon [final/published May 2010, see link below]).

Now [April 20 2010] a genetic analysis of nearly 2,000 people from around the world indicates that humans interbred with extinct species twice, leaving their genes within the DNA of people today!

The researchers arrived at that conclusion by studying genetic data from 1,983 individuals from 99 populations in Africa, Europe, Asia, Oceania and the Americas. Sarah Joyce, a doctoral student working with Long, analyzed 614 microsatellite positions, which are sections of the genome that can be used like fingerprints. She then created an evolutionary tree to explain the observed genetic variation in microsatellites. The best way to explain that variation was if there were two periods of interbreeding between humans and an archaic species, such as Homo neanderthalensis or H. heidelbergensis.

Using projected rates of genetic mutation and data from the fossil record, the researchers suggest that the interbreeding happened about 60,000 years ago in the eastern Mediterranean and, more recently, about 45,000 years ago in eastern Asia. Those two events happened after the first H. sapiens had migrated out of Africa, says Long. His group didn’t find evidence of interbreeding in the genomes of the modern African people included in the study.

Note about Homo sapiens and neanderthalensis ancestor from wikipedia:

Heidelbergensis is the direct ancestor of H. sapiens and H. neanderthalensis. Neanderthals diverged from H. heidelbergensis probably some 300,000 years ago in Europe, during the Wolstonian Stage; H. sapiens probably diverged between 200,000 and 100,000 years ago in Africa.
Homo neanderthalensis retained most of the features of H. heidelbergensis after its divergent evolution. Though shorter, Neanderthals were more robust, had large brow-ridges, a slightly protruding face and lack of prominent chin. They also had a larger brain than all other hominins [1200–1900 cm3 skull capacity vs ~ 1350 cm3 for human]. Homo sapiens, on the other hand, has the smallest brows of any known hominin, was tall and lanky, and had a flat face with a protruding chin. H. sapiens has a larger brain than H. heidelbergensis, and a smaller brain than H. neanderthalensis

see also: Comparing Neanderthals and modern humans

references:

Nature News report

May 6 2010 updates:
(not about the microsatellite study but based on the complete genome. They arrive at the same conclusion!)

Neanderthal genes ‘survive in us’ (BBC News)

A Draft Sequence of the Neandertal Genome (Science)

The data suggest that between 1 and 4% of the genomes of people in Eurasia are derived from Neandertals.
...
A striking observation is that Neandertals are as closely related to a Chinese and Papuan individual as to a French individual, even though morphologically recognizable Neandertals exist only in the fossil record of Europe and western Asia. Thus, the gene flow between Neandertals and modern humans that we detect most likely occurred before the divergence of Europeans, East Asians, and Papuans. This may be explained by mixing of early modern humans ancestral to present-day non-Africans with Neandertals in the Middle East before their expansion into Eurasia.

Targeted Investigation of the Neandertal Genome by Array-Based Sequence Capture (Science)

we have identified 88 amino acid substitutions that have become fixed in humans since our divergence from the Neandertals.

Dec. 22 2010

Sequencing of Denisova hominin (based on nuclear DNA extracted from a finger boneand a tooth!) shows that it interbreed with Asian human population (itself, like all non african populations, having interbreed with Neandertals) around 50,000 years ago.
bbc news article
nature article – Human origins: Shadows of early migrations


© bbc.co.uk

July 2011

Genetic research confirms that non-Africans are part Neanderthal

When the Neanderthal genome was sequenced in 2010, they quickly compared 6000 chromosomes from all parts of the world to the Neanderthal haplotype. The Neanderthal sequence was present in peoples across all continents, except for sub-Saharan Africa, and including Australia.
There is little doubt that this haplotype is present because of mating with our ancestors and Neanderthals.


Add a comment:

(required)

(will not be published) (required)

(optional)

(ascii characters only)