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Research supported in part by NHGRI provides the strongest genomic evidence to date that more males than females participated in the human dispersal out of Africa 60,000 to 100,000 years ago. The finding is based on analysis of very large DNA data sets collected from four geographically diverse populations and compared patterns of genetic variation between the sex chromosome X and the non-sex chromosomes (autosomes). The analysis detected accelerated genetic drift beyond what would be expected on the X chromosome relative to the autosomes. Genetic drift is the tendency over many generations for a chance mutation to become a more common variation within the genome of a species. The significant difference in variation led the authors to conclude that a disproportionately larger number of males than females migrated out of the African continent to establish the founding population which later split into the European and Asian populations. James Mullikin, Ph.D., associateinvestigator, Genome Technology Branch, NHGRI, co-authored the paper with colleagues at the Harvard Medical School and the Broad Institute of Harvard and MIT. "We can now get a better glimpse of the migration patterns during in the African dispersion event(s)," he said, noting that his role included preparing the large datasets while maintaining the fidelity of the underlying signals for the analysis to pick up on these historic events. Accelerated genetic drift on chromosome X during the human dispersal out of Africa is published in the December 21, 2008 advance online issue of the journal Nature Genetics.
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In a study published Dec. 5, 2008 in PLoS Genetics, a research team led by Kyungjae Myung, Ph.D., proposed a new molecular pathway for gross chromosomal rearrangements, which are frequently observed in many cancers. They observed gross chromosomal rearrangement in cells with high expression of a specific oncogene, providing a mechanistic bridge between transcription and genomic instability. Spt2p Defines a New Transcription-Dependent Gross Chromosomal Rearrangement Pathway.
[Full Text] PLoS Genetics, Dec. 5, 2008.
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Three papers in the Dec. 07, 2008 advance online edition of Nature Genetics include co-authors from NHGRI's Genome Technology Branch.
One study examined genetic variants and cholesterol levels in more than 40,000 individuals, and locating 30 genetic variants associated with cholesterol levels, including 11 new ones. Several of the newly implicated genetic variants were also related to risk of gallstones and certain rare forms of diabetes.
Lori L. Bonnycastle, Kari A. Kubalanza, Mario A. Morken, Amy J. Swift and Francis S. Collins, and a large group of international collaborators were among the co-authors. Support for the research includes intramural funding and extramural grants from NHGRI. Common variants at 30 loci contribute to polygenic dyslipidemia [Full Text]
A study that looked at the genomes of 36,000 individuals identified genetic changes in the melatonin receptor gene that are strongly associated with a small increase in glucose levels in non-diabetic individuals. The same changes increased the risk of developing diabetes by up to 20 percent. Michael R. Erdos, Lori L. Bonnycastle, Francis S. Collins and a large group of international collaborators were among the co-authors. Support for the research includes intramural funding and extramural grants from NHGRIVariants in MTNR1B influence fasting glucose levels
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The third study accompanies the findings regarding changes in the melatonin receptor gene and impaired insulin secretion. Co-authors included Michael R. Erdos. Funding for the work included support from the NHGRI intramural program.
Common variant in MTNR1B associated with increased risk of type 2 diabetes and impaired early insulin secretion
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NHGRI's James C. Mullikin, Ph.D., Genome Technology Branch, and Fabio Candotti, M.D. and Karen L. Simon-Stoos, both of the Genetic and Molecular Biology Branch, are co-authors of a study that identified a previously unknown mechanism involved in regulation of hematopoietic cell differentiation in one of the most severe human immunodeficiency syndromes. Dr. Mullikin and colleagues at the NIH Intramural Sequencing Center discovered the first mutations in the adenylate kinase 2 (AK2) gene in several patients. Dr. Candotti's group performed the fine mapping of some of those mutations, and found new ones in other patients. The disease combines maturation arrest in the myeloid lineage and global impairment of lymphoid maturation. In addition, affected patients have deafness. Knowing the gene responsible opens the way to learning more about the steps needed for the correct development of the development of the lymphoid and myeloid systems, as well as that of the ear. It also provides a tool for specific early and
possibly prenatal molecular diagnosis. Human adenylate kinase 2 deficiency causes a profound haematopoietic defect associated with sensorineural deafness is in the Nov. 30, 2008 online issue of Nature Genetics.
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NHGRI's Vence L. Bonham, J.D. and Erin M. Ramos, Ph.D., M.P.H. are authors of a commentary on a study that alerts the Canadian biomedical community of disparities in the health of an African Canadian group, suggesting that the findings may guide new health interventions to improve the health of racial and ethnic minorities in North America. The commentary titled, Unravelling the contribuions of social, environmental and genetic factors to health differences, is in the September 23, 2008 issue of the Canadian Medical Association Journal.
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NHGRI's Dr. Benjamin Feldman and colleagues describe a method for viably isolating embryonic cells in zebrafish, which opens up numerous experimental possibilities for developmental biologists. The article, Transcriptional profiling of endogenous germ layer precursor cells identifies dusp4 as an essential gene in zebrafish endoderm specification, is in the August 26, 2008 issue of the Proceedings of the National Academy of Sciences.
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In an article in the August 26, 2008 issue of the Proceedings of the National Academy of Sciences, NHGRI's Dr. Kyungjae Myung and colleagues report on the role of the genes HLTF and SHPRH in maintaining genomic stability in human cells. Polyubiquitination of proliferating cell nuclear antigen by HLTF and SHPRH prevents genomic instability from stalled replication forks. [Full Text] |
| Elaine Ostrander, Ph.D., chief and senior investigator, Cancer Genetics Branch, NHGRI, has carved out a research niche with her study of dog genetics and human cancer. Dr. Ostrander is the subject of an inspiring profile in the August 2008 issue of The Scientist titled, Going to the Dogs.
[Full Text] The Scientist, August 2008 |
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In a commentary published in the August 2008 issue of Nature Genetics, Colleen McBride, Ph.D., chief and senior investigator, Social and Behavioral Research Branch, and colleagues, discuss the urgent need for a multifaceted research agenda to reap the full benefits and avoid the potential pitfalls of personalized genomics. While a number of companies are now marketing genetically based risk profiles directly to consumers for a range of common diseases, the clinical utility of this information — and its impact on the behavior of those receiving it — is poorly understood. The authors outline the range of questions that need to be answered to better understand the implications of personalized genomics and discuss the early phase of an ongoing research project, the Multiplex Initiative.
[Full Text] Nature, July 29, 2008 |
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In a study published May 13, 2008 in Developmental Cell, a research team led by Dr. Yingzi Yang, et al, reports that a cell signaling pathway, called Hedgehog signaling, regulates bone formation and resorption and reduces bone loss in aged mice. Hedgehog Signaling in Mature Osteoblasts Regulates Bone Formation and Resorption by Controlling PTHrP and RANKL Expression.
[Summary] [Full Text]Developmental Cell, May 13, 2008 |
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In the November 2007 issue of Genome Research,
NHGRI researchers Elaine A. Ostrander, Ph.D. and colleagues describe a multi-breed approach to identifying causative mutations in mapping common diseases in modern dog breeds. Now Available: Breed relationships facilitate fine mapping studies: A 7.8Kb deletion cosegregates with collie eye anomaly across multiple dog breeds. [Full Text] Genome Research, November 2007. |
| Dr. Pamela Schwartzberg Inducted into the Association of American Physicians Pamela Schwartzberg, M.D., Ph.D., senior investigator in the Genetic Disease Research Branch, is a 2008 inductee into the Association of American Physicians (AAP). She was inducted at AAP's annual meeting in Chicago, April 25-27, 2008. |
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NHGRI researchers Dawn Watkins-Chow, Ph.D., and William J. Pavan, Ph.D. report in the January 2008 issue of Genome Research the discovery of variation within a single substrain of C57BL/6 laboratory mice. The NHGRI Genetic Disease Research Branch Mouse Embryology Section researchers identified a region of the genome that varies within the single strain even though the strain has been inbred for many generations to produce large numbers of nearly identical mice for research. They report that for the region we identified, the structural variation in the genome alters gene expression. Genomic copy number and expression variation within the C57BL/6J inbred mouse strain. [Full Text ] Genome Research, January 2008. |
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