World's most advanced genetic map created
A consortium led by scientists at the University of Oxford and Harvard Medical School has constructed the world's most detailed genetic map.
A genetic map specifies the precise areas in the genetic material of a sperm or egg where the DNA from the mother and father has been reshuffled in order to produce this single reproductive cell. The biological process whereby this reshuffling occurs is known as "recombination." While almost every genetic map built so far has been developed from people of European ancestry, this new map is the first constructed from African American recombination genomic data.
"This is the world's most accurate genetic map," said David Reich, professor of genetics at Harvard Medical School, who co-led the study with Simon Myers, a lecturer in the Department of Statistics at the University of Oxford.
The researchers were surprised to find that positions where recombination occurs in African Americans are significantly different from non-African populations.
"The landscape of recombination has shifted in African Americans compared with Europeans," said Anjali Hinch, first author and a post-graduate student at Oxford University's Wellcome Trust Centre for Human Genetics.
Simon Myers added, "More than half of African Americans carry a version of the biological machinery for recombination that is different than Europeans. As a result, African Americans experience recombination where it almost never occurs in Europeans."
The findings will be published in the July 21 edition of Nature.
An independent study that used a similar strategy to build a genetic map in African Americansled by University of California, Los Angeles, scientists Daniel Wegmann, Nelson Freimer and John Novembrewill be published in Nature Genetics.
Scientists have only recently begun to explore the genetic differences between individuals and populations and the role those differences play in human health. In that respect, the first draft of the human genome, completed a decade ago, was only a starting point for understanding the genetic origins of disease.
As researchers begin to parse those differences, a crucial tool is a genetic map, which in this case was based on where recombination has occurred across the genome. Recombination, together with mutation, accounts for all the genetic (and thus physical) variety we see within species. But while mutation refers to the errors introduced into single locations within genomes when cells divide, recombination refers to the process by which huge chunks of chromosomes are stitched together during sexual reproduction.
But this stitching process only occurs at specific locations. In a prior landmark set of papers, Myers and his colleagues identified a DNA code, or motif, that attracted part of the recombination machinery, a gene called PRDM9. Knowing the motif, a string of 13 DNA letters, researchers could zero in on the locations where recombination typically occurredthe "recombination hotspots."
"When recombination goes wrong, it can lead to mutations causing congenital diseases, for example diseases like Charcot-Marie-Tooth disease, or certain anemias," said Myers. "We found the same 13 base motif marking many of these disease mutation sites."
Explained Reich, "The places in the genome where there are recombination hotspots can thus also be disease hotspots. Charting recombination hotspots can thus identify places in the genome that have an especially high chance of causing disease."
The researchers discovered that the 13 base-pair motif that is responsible for many of the hotspots in Europeans accounts for only two thirds as much recombination in African Americans. They connected the remaining third to a new motif of 17 base pairs, which is recognized by a version of the recombinational machinery that occurs almost exclusively in people of African ancestry.
These findings are expected to help researchers understand the roots of congenital conditions that occur more often in African Americans (due to mutations at hotspots that are more common in African Americans), and also to help discover new disease genes in all populations, because of the ability to map these genes more precisely.
The new map is so accurate because African American individuals often have a mixture of African and European ancestry from over the last two hundred years. David Reich and Simon Myers are experts in analyzing genetic data to reconstruct the mosaic of regions of African and European genetic ancestry in DNA of African Americans. By applying a computer program they previously wrote, Anjali Hinch identified the places in the genomes where the African and European ancestry switches in almost 30,000 people, detecting about 70 switches per person. These areas corresponded to recombination events in the last few hundred years. Thus, the researchers identified more than two million recombination events that they used to build the map.
The study was only possible because of collaboration from 81 co-authors, using DNA samples from five large studies that have been carried out to study common diseases such as heart disease and cancer, funded by the National Institutes of Health, the Department of Defense, and many private foundations.
Said James Wilson, a professor at the University of Mississippi Medical Center who was responsible for coordinating the collaboration, "All the co-authors worked together in an incredibly collegial way to put together the enormous set of samples and high quality genetic data that made this study a success."
More information: The recombination map is available at www.well.ox.ac.uk/… njali/AAmap/
Provided by Harvard Medical School
- Scientists generate the most precise map of genetic recombination ever Jul 10, 2008 | not rated yet | 0
- Study maps hotspots of genetic rearrangement Apr 05, 2011 | not rated yet | 0
- Genetic ancestry of African-Americans reveals new insights about gene expression Dec 05, 2008 | not rated yet | 0
- New mathematical model to add rigor to studies of disease genetics and evolution Mar 19, 2007 | not rated yet | 0
- DNA fingerprinting pioneer discovers role of key genetic catalyst for human diversity Sep 05, 2010 | not rated yet | 0
- Motion perception revisited: High Phi effect challenges established motion perception assumptions Apr 23, 2013 | 3 / 5 (2) | 2
- Anything you can do I can do better: Neuromolecular foundations of the superiority illusion (Update) Apr 02, 2013 | 4.5 / 5 (11) | 5
- The visual system as economist: Neural resource allocation in visual adaptation Mar 30, 2013 | 5 / 5 (2) | 9
- Separate lives: Neuronal and organismal lifespans decoupled Mar 27, 2013 | 4.9 / 5 (8) | 0
- Sizing things up: The evolutionary neurobiology of scale invariance Feb 28, 2013 | 4.8 / 5 (10) | 14
Classical and Quantum Mechanics via Lie algebras
Apr 15, 2011 I'd like to open a discussion thread for version 2 of the draft of my book ''Classical and Quantum Mechanics via Lie algebras'', available online at http://lanl.arxiv.org/abs/0810.1019 , and for the...
- More from Physics Forums - Independent Research
More news stories
Researchers from Queen Mary, University of London have led the largest sequencing study of human disease to date, investigating the genetic basis of six autoimmune diseases.
Genetics 11 hours ago | 4 / 5 (1) | 0 |
University of Minnesota Medical School researchers from the Masonic Cancer Center, University of Minnesota, in partnership with the University's Brain Tumor Program, have developed a new mouse model of malignant peripheral ...
Genetics May 20, 2013 | 5 / 5 (1) | 0 |
Northwestern University scientists have shown a gene involved in neurodegenerative disease also plays a critical role in the proper function of the circadian clock.
Genetics May 16, 2013 | 3 / 5 (1) | 1 |
Informed consent is the backbone of patient care. Genetic testing has long required patient consent and patients have had a "right not to know" the results. However, as 21st century medicine now begins to use the tools of ...
Genetics May 16, 2013 | 5 / 5 (1) | 3 |
Ethicists provide framework supporting new recommendations on reporting incidental findings in gene sequencing
In a paper published in Science Express, a group of experts led by bioethicists in the Center for Medical Ethics and Health Policy at Baylor College of Medicine provide a framework for the new American College of Medical Geneti ...
Genetics May 16, 2013 | not rated yet | 0
Existing research shows that bicyclists who wear helmets have an 88 percent lower risk of brain injury, but researchers at Boston Children's Hospital found that simply having bicycle helmet laws in place showed a 20 percent ...
18 minutes ago | not rated yet | 0
Swiss scientists reveal the mechanism responsible for aging hidden deep within mitochondria—and dramatically slow it down in worms by administering antibiotics to the young.
11 hours ago | 4.9 / 5 (7) | 0 |
Until now, little was scientifically known about the human potential to cultivate compassion—the emotional state of caring for people who are suffering in a way that motivates altruistic behavior.
8 hours ago | 5 / 5 (2) | 2 |
(HealthDay)—Migraines and depression can each cause a great deal of suffering, but new research indicates the combination of the two may be linked to something else entirely—a smaller brain.
7 hours ago | 5 / 5 (1) | 0 |
A new approach for immunizing against influenza elicited a more potent immune response and broader protection than the currently licensed seasonal influenza vaccines when tested in mice and ferrets. The vaccine ...
8 hours ago | not rated yet | 0 |
Calorie information in fast food restaurants used by 40 percent of 9-18 year olds when making food choices
A new study published online today (Thursday) in the Journal of Public Health has found that of young people who visited fast food or chain restaurants in the U.S. in 2010, girls and youth who were obese were more likely ...
5 hours ago | not rated yet | 0