New genome sequences from two extinct human relatives suggest that these ‘archaic’ groups bred with humans and with each other more extensively than was previously known.
The ancient genomes, one from a Neanderthal and one from a different archaic human group, the Denisovans, were presented on 18 November at a meeting at the Royal Society in London. They suggest that interbreeding went on between the members of several ancient human-like groups living in Europe and Asia more than 30,000 years ago, including an as-yet unknown human ancestor from Asia.
“What it begins to suggest is that we’re looking at a ‘Lord of the Rings’-type world — that there were many hominid populations,” says Mark Thomas, an evolutionary geneticist at University College London who was at the meeting but was not involved in the work. Read more.
The genome of a recently discovered branch of extinct humans known as the Denisovans that once interbred with us has been sequenced, scientists said today.
Genetic analysis of the fossil revealed it apparently belonged to a little girl with dark skin, brown hair and brown eyes, researchers said. All in all, the scientists discovered about 100,000 recent changes in our genome that occurred after the split from the Denisovans. A number of these changes influence genes linked with brain function and nervous system development, leading to speculation that we may think differently from the Denisovans. Other changes are linked with the skin, eyes and teeth.
"This research will help [in] determining how it was that modern human populations came to expand dramatically in size as well as cultural complexity, while archaic humans eventually dwindled in numbers and became physically extinct," said researcher Svante Pääbo at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. Read more.
A mummified child in Korea whose organs were relatively well preserved has produced the oldest full viral genome description. A liver biopsy of the mummy revealed a unique hepatitis B virus (HBV) known as a genotype C2 sequence, which is said to be common in Southeast Asia.
The first discovery of hepatitis in a Korean mummy came in 2007. The new work provided more detailed analysis.
The research, announced today, was detailed in the May 21 edition of the scientific journal Hepatology.
Carbon 14 tests of the clothing of the mummy suggests that the boy lived around the 16th century during the Korean Joseon Dynasty. The viral DNA sequences recovered from the liver biopsy enabled the scientists to map the entire ancient hepatitis B viral genome. Read more.
Researchers have discovered a gene duplication related to the human brain that may have been responsible for adaptive evolutionary changes leading from ancient primate ancestors to modern humans. According to the scientists who participated in the study, two gene duplications occurred that were related to brain development, an aspect of change that was key to the emergence of ancestral and, ultimately, modern humans.
"There are approximately 30 genes that were selectively duplicated in humans," said Franck Polleux, a study participant and expert in brain development at The Scripps Research Institute. "These are some of our most recent genomic innovations."
Polleux and Evan Eichler, who is a genome scientist at the University of Washington, focused on a key gene known as SRGAP2. This gene was apparently duplicated at least twice over the past four million years, once about 3.5 million years ago and again about 2.5 million years ago. Read more.
Scientists already know from genetic evidence that human populations of Africa and Europe mixed in ancient times, from the days of the Roman Empire through to the slave trade of the colonial period. But evidence of any mixing prior to that has been comparatively less abundant. Now, researchers conclude from a recently completed study (published online on March 27, 2012 in Genome Research) that genetic material was exchanged between Europe and Africa as far back as 11,000 years ago, or more.
"It was very surprising to find that more than 35 percent of the sub-Saharan lineages in Europe arrived during a period that ranged from more than 11,000 years ago to the Roman Empire times," said senior study author Dr. Antonio Salas of the University of Santiago de Compostela. The other 65% of European lineages showing African lineage represent population groups that arrived more recently.
The researchers analyzed and compared mtDNA genome sequences from different regions of Europe with that of other groups around the world. During this process they analyzed the mtDNA genomes of “haplogroup L”, (a lineage of sub-Saharan African origin) in Europe. Read more.
The world’s most famous frozen corpse has had his genome sequenced. An international team has today published the almost complete DNA sequence of Ötzi the Tyrolean Iceman in Nature Communications, and has found clues as to the whereabouts of his closest living relations.
Hikers discovered Ötzi’s 5,300-year-old body in the Alps near the Italian–Austrian border in 1991. It was well preserved, and has become one of the most studied cadavers in science. Researchers have already discovered that Ötzi suffered from hardened arteries and tooth cavities, bore tattoos and gorged on ibex before dying with an arrow lodged in his back — but there is still more information to be gained from his body.
We would like to know as much as possible about his living conditions, about himself and also his cause of death. Read more.
An international team of researchers studying DNA patterns from modern and archaic humans has uncovered new clues about the movement and intermixing of populations more than 40,000 years ago in Asia.
Using state-of-the-art genome analysis methods, scientists from Harvard Medical School and the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, have found that Denisovans—a recently identified group of archaic humans whose DNA was extracted last year from a finger bone excavated in Siberia—contributed DNA not just to present-day New Guineans, but also to aboriginal Australian and Philippine populations.
The study demonstrates that contrary to the findings of the largest previous genetic studies, modern humans settled Asia in more than one migration. According to David Reich, a professor of genetics at Harvard Medical School, “Denisova DNA is like a medical imaging dye that traces a person’s blood vessels. It is so recognizable that you can detect even a little bit of it in one individual. In a similar way, we were able to trace Denisova DNA in the migrations of people. This shows the power of sequencing ancient DNA as a tool for understanding human history.” Read more.