ISEN-ASTC-L is a service of the Association of Science-Technology Centers Incorporated, a worldwide network of science museums and related institutions. ***************************************************************************** On May 7 th an extra ordinary study was published in Science which reported an analysis of a portion of the Neandertal genome and suggested that there was inter breeding between Neandertals and modern humans. This is very important with implications for our understanding our evolution and our origins. Science is making these all available to non-subsribers to the magazine. Let me know if you have an difficulties finding the articles. Martin The article http://www.sciencemag.org/cgi/content/full/328/5979/680 I sent yesterday is a good news summary of the recently (May 7, 2010) publication of the Neandertal genome and the discovery of admixture of Neandertal genes with modern humans due to interbreeding in what is now the Near East. However AAAS has created a section of their website The Neandertal Genome-Background which puts the research into perspective; http://www.sciencemag.org/special/neandertal/feature/index.html. There are two sections, I've copied below which are particularly interesting. One has to do with the question of interbreeding of Neandertals, especially in in Europe where there is ample fossil evidence of the co-existance for some time of Neandertals and modern human; the other is about the implications for theories about the origins of modern humans. modern humans who migrated out of Africa. The technical breakthroughs that allowed this study can also be used to study the genomes of other human fossils especially the recent discovery in Africa of a suggested branch in human evolution and Flores in the Philippines which should provide ore information about our origins and evolution. Stay tuned as it is going to be a wild ride. There is an podcast http://www.sciencemag.org/cgi/content/full/328/5979/764-b about this discovery as well as audio interviews with principles on the Neandertal Genome Background pages. Neandertals seem to have better cold adapted than modern humans. However, the preliminary genome results seem not to show that these genes in modern humans. This is surprising as it would seem that it would be of advantage to modern humans living in Europe. Some of the scientists quoted in the podcast suggest that the earlier data be reviewed. Substantial controversy surrounds the question of whether Neandertals interbred with modern humans. To address this question, Green *et al*. tested whether Neandertals are more closely related to some present-day humans than to others.* Because modern humans are believed to have originated in Africa, if Neandertals diverged from modern humans before present-day populations began to differentiate, one would expect Neandertal sequences to match sequences from non-Africans and Africans to the same extent. Unexpectedly, the researchers found that Neandertals share more genetic variants with present-day non-Africans than with Africans. These results can be explained if gene flow occurred from Neandertals into the ancestors of non-Africans. The observation that the Neandertal genome appears as closely related to the genome of a Chinese and a Papua New Guinean individual as to the genome of a French individual is particularly surprising as there is, to date, no fossil evidence that Neandertals existed in East Asia or Papua New Guinea. Green *et al*. thus suggest that gene flow between Neandertals and modern humans occurred prior to the divergence of European and Asian populations. Based on comparative genomic data, as well as a mathematical model of gene flow, the authors further estimate that between 1 and 4% of the genomes of people in Eurasia may be derived from Neandertals. *For a description of additional methods used by Green *et al*. to detect gene flow between Neandertals and modern humans, see the News story<http://www.sciencemag.org/cgi/content/summary/328/5979/680> by A. Gibbons. There are two major competing hypotheses about the origins of modern humans. The "Out of Africa" hypothesis posits that modern humans evolved from a small population in Africa and replaced all other hominin populations, including Neandertals, as they migrated into Europe and Asia. The simplest form of this model assumes no interbreeding between modern and ancestral human populations. In contrast, the "Multiregional" hypothesis holds that modern humans evolved in several regions of the world simultaneously. According to this view, archaic humans were not replaced by anatomically modern humans, but rather, gene flow between Africa, Europe, and Asia, led to the evolution of modern humans from local populations. The finding that Neandertals are on average closer to individuals in Eurasia than to individuals in Africa thus presents a challenge to the strictest version of the "Out of Africa" model; however variations of this model are plausible. Green *et al*. suggest that mixing of early modern humans ancestral to present-day non-Africans with Neandertals is likely to have occurred in the Middle East prior to their expansion into Eurasia. The authors contend that this scenario is compatible with the archaeological record, which shows that modern humans appeared in the Middle East before 100,000 years ago while the Neandertals existed in the same region after this time, perhaps until 50,000 years ago. Although the Green *et al*. analyses are suggestive of admixture, the role of Neandertals in the genetic ancestry of humans outside of Africa was likely relatively minor given that only a few percent of the genomes of present-day people outside of Africa appear to be derived from Neandertals. More fossil and genetic data will help researchers further resolve the relationships between our early ancestors and how they shaped modern human evolution. -- ––––––––––––––––––––––––––––––––––––––––– Martin Weiss, PhD Science Interpretation, Consultant New York Hall of Science *********************************************************************** For information about the Association of Science-Technology Centers and the Informal Science Education Network please visit www.astc.org. Check out the latest case studies and reviews on ExhibitFiles at www.exhibitfiles.org. The ISEN-ASTC-L email list is powered by LISTSERVR software from L-Soft. To learn more, visit http://www.lsoft.com/LISTSERV-powered.html. To remove your e-mail address from the ISEN-ASTC-L list, send the message SIGNOFF ISEN-ASTC-L in the BODY of a message to [log in to unmask]