A group of Norwegian and American researchers have shown that common variations in genes associated with microcephaly -- a neuro-developmental disorder in which brain size is dramatically reduced -- may explain differences in brain size in healthy individuals as well as in patients with neurological and psychiatric disorders.
The study, which involved collaboration between researchers from the University of Oslo, the University of California, San Diego and Scripps Translational Science Institute in La Jolla, California, will be published online the week of December 21 in the Proceedings of the National Academy of Science.
In relation to body size, brain size has expanded dramatically throughout primate and human evolution. In fact, in proportion to body size, the brain of modern humans is three times larger than that of non-human primates. The cerebral cortex in particular has undergone a dramatic increase in surface area during the course of primate evolution.
Science & Technology
The discovery sheds light on how people lived 2,000 years ago, when Christians believe Jesus was growing up there, Israel's Antiquities Authority said.
A spokeswoman said Jesus and his childhood friends likely knew the home.
It was found near the place where angel Gabriel is believed to have told Mary that she would give birth to Jesus.
Fossil of early hominid heads the journal's list of top 10 scientific advances of 2009.
The research that brought to light the fossils of Ardipithecus ramidus, a hominid species that lived 4.4 million years ago in what is now Ethiopia, has topped Science's list of this year's most significant scientific breakthroughs. The monumental find predates "Lucy," - previously the most ancient partial skeleton of a hominid on record - by more than one million years, and it inches researchers ever-closer to the last common ancestor shared by humans and chimpanzees.
The research that brought to light the fossils of Ardipithecus ramidus, a hominid species that lived 4.4 million years ago in what is now Ethiopia, has topped Science's list of this year's most significant scientific breakthroughs. The monumental find predates "Lucy," - previously the most ancient partial skeleton of a hominid on record - by more than one million years, and it inches researchers ever-closer to the last common ancestor shared by humans and chimpanzees.
© NASA/CXC/UCSC/L. Lopez et al.
A new study of images from NASA's Chandra X-ray Observatory on supernova remnants - the debris from exploded stars - shows that the symmetry of the remnants, or lack thereof, reveals how the star exploded. This is an important discovery because it shows that the remnants retain information about how the star exploded even though hundreds or thousands of years have passed.
"It's almost like the supernova remnants have a 'memory' of the original explosion," said Laura Lopez of the University of California at Santa Cruz, who led the study. "This is the first time anyone has systematically compared the shape of these remnants in X-rays in this way."
© iStockphoto/Eva Serrabassa
Girl decorating a Christmas tree, which has seven times more DNA than she does.
Girl decorating a Christmas tree, which has seven times more DNA than she does.
Coniferous trees have dominated major parts of the earth for hundreds of millions of years. When primitive batrachians crawled around Carbon Age forests, they were surrounded by conifers. Conifers survived the geological disaster 250 million years ago that paved the way for the age of the dinosaurs. When the impact of a meteorite wiped out the dinosaurs, conifers lived on. Today conifers dominate major regions of the earth -- the combined weight of all the people on earth is less than that of the conifers in Jämtland County in central Sweden.
Apparently conifers managed as early as 300 million years ago to create an extremely successful genetic make-up that has allowed them to dominate the globe, but what does it look like? All conifers have twelve chromosomes, but they are extremely large: a cell from a spruce or pine has seven times as much DNA as a human cell does. Why do conifers have so much DNA? Does it have to do with their having thrived for millions of years on earth, and do they really have more genes than you and I, or are their genes simply more 'diluted'? This is not known, but their enormous amount of DNA has entailed that scientists have not dared to tackle a mapping of the complete genome of coniferous trees.
© Mads Ravn/Courtesy of The University of Stavanger
The archaeologists found that Vanuatu skeletons are headless.
The archaeologists found that Vanuatu skeletons are headless.
"This is a groundbreaking discovery, as it is the oldest and biggest skeleton find ever in the Pacific Ocean; bigger cemeteries found further east are much younger," says Mads Ravn, head of research at the University of Stavanger's Museum of Archaeology in Norway.
Relatives did not treat their dead gently. Besides being headless, some of them had had their arms and legs broken, in order to fit into the coral reef cavities. Ravn suggests they may have been left to rot first, and buried later as skeletons.
The local museum's staff of the Vanuatu Culture Centre, a range of researchers, lead by Stuart Bedford and Matthew Spriggs from the Australian National University (ANU), forms an international and cross-disciplinary team, working to gather information about the Pacific islands' inhabitants. Mads Ravn's expertise in migration and colonising over great distances, as well as in digital excavation documentation and recording, makes him an important contributor to this cooperative effort.
Researchers at Emory University School of Medicine have determined the structures of two enzymes that customize histones, the spool-like proteins around which DNA coils inside the cell.
The structures provide insight into how DNA's packaging is just as important and intricate as the information in the DNA itself, and how these enzymes are part of a system of inspectors making sure the packaging is in order.
The results are published online this week in the journal Nature Structural and Molecular Biology.
A team of scientists led by Xiaodong Cheng, PhD, professor of biochemistry at Emory and a Georgia Research Alliance eminent scholar, used X-rays to probe the architecture of two enzymes, PHF8 and KIAA1718. The enzymes are known as histone demethylases because they remove methyl groups (chemical modifications of a protein) from histones.
The structures provide insight into how DNA's packaging is just as important and intricate as the information in the DNA itself, and how these enzymes are part of a system of inspectors making sure the packaging is in order.
The results are published online this week in the journal Nature Structural and Molecular Biology.
A team of scientists led by Xiaodong Cheng, PhD, professor of biochemistry at Emory and a Georgia Research Alliance eminent scholar, used X-rays to probe the architecture of two enzymes, PHF8 and KIAA1718. The enzymes are known as histone demethylases because they remove methyl groups (chemical modifications of a protein) from histones.
Not all regions of a tumor are equal in terms of their oxygen levels. One clinically important implication of this is that tumors with large areas with low levels of oxygen (areas known as hypoxic regions) are associated with poor prognosis and treatment response.
A team of researchers, led by Bradly Wouters, at the University of Toronto, Canada, has determined that a cellular response pathway known as the unfolded protein response pathway helps protect human tumor cells from hypoxia and anticancer irradiation treatment.
Further analysis indicated that the unfolded response pathway increased expression of two proteins involved in a cellular process known as autophagy, which is known to act to protect cells in times of stress.
Importantly, inhibition of autophagy sensitized cultured human tumor cells to hypoxia and sensitized human tumors xenografted into mice to irradiation, leading the authors to suggest that targeting the molecules they identified as important might be of clinical benefit.
A team of researchers, led by Bradly Wouters, at the University of Toronto, Canada, has determined that a cellular response pathway known as the unfolded protein response pathway helps protect human tumor cells from hypoxia and anticancer irradiation treatment.
Further analysis indicated that the unfolded response pathway increased expression of two proteins involved in a cellular process known as autophagy, which is known to act to protect cells in times of stress.
Importantly, inhibition of autophagy sensitized cultured human tumor cells to hypoxia and sensitized human tumors xenografted into mice to irradiation, leading the authors to suggest that targeting the molecules they identified as important might be of clinical benefit.
Choosing the right cell type is particularly important in genetic studies. This is apparent from research published on 16 October in PLoS Genetics. Dutch researcher Alice Gerrits has shown how variations in the genome can influence the activity of genes. This effect was found to be strongly dependent on the cell type in which these genes were active.
Although all the cells in our body contain essentially the same DNA (genome), they do not all exhibit the same functions. This is usually because different sets of genes are active in different types of cells. Gerrits investigated four types of blood cells in 25 mouse strains with slightly different genomes. In each of the four cell types, she looked for differences in gene activity between the 25 mouse strains and determined which pieces of the genome caused these differences. She discovered that some pieces of the genome had the same effect on the activity of genes in all four cell types. Yet interestingly, a far larger number of pieces exerted an effect on gene activity mostly in one, two or three of the four cell types.
Although all the cells in our body contain essentially the same DNA (genome), they do not all exhibit the same functions. This is usually because different sets of genes are active in different types of cells. Gerrits investigated four types of blood cells in 25 mouse strains with slightly different genomes. In each of the four cell types, she looked for differences in gene activity between the 25 mouse strains and determined which pieces of the genome caused these differences. She discovered that some pieces of the genome had the same effect on the activity of genes in all four cell types. Yet interestingly, a far larger number of pieces exerted an effect on gene activity mostly in one, two or three of the four cell types.
Shipwreak hunters have found the hospital ship Centaur which was torpedoed without warning in 1943 off the Queensland coast, killing 268 people.
Search director David Mearns has advised government officials of the exact location of the wreck and said filming of the wreck would begin in January.
Acting Prime Minister Julia Gillard said Australians and relatives of those who had been aboard the ship were grateful for the find.
"The discovery of the AHS Centaur will ensure all Australians know and commemorate the 268 brave nurses and crew who died in the service of their nation," Ms Gillard said.
"I hope by locating the final resting place of the AHS Centaur, the family and friends of those men and women who were tragically lost find some resolution."
Search director David Mearns has advised government officials of the exact location of the wreck and said filming of the wreck would begin in January.
Acting Prime Minister Julia Gillard said Australians and relatives of those who had been aboard the ship were grateful for the find.
"The discovery of the AHS Centaur will ensure all Australians know and commemorate the 268 brave nurses and crew who died in the service of their nation," Ms Gillard said.
"I hope by locating the final resting place of the AHS Centaur, the family and friends of those men and women who were tragically lost find some resolution."
