Beyond the simple stream of one-letter characters in the human genome sequence lies a complex, higher-order code. In order to decipher this level of architecture, scientists have developed powerful new experimental and algorithmic methods to detect copy number variants (CNVs)--defined as large deletions and duplications of DNA segments. These technologies--reported today in the journal Genome Research--were used to create the first comprehensive map of CNVs in the human genome, concurrently published in Nature. A related article appears in Nature Genetics.
CNVs are responsible for genetic changes in Alzheimer's and Parkinson's, susceptibility to HIV-1, some forms of color blindness, and many other diseases. They lead to variation in gene expression levels and may account for a large amount of phenotypic variation among individuals and ethnic populations, including differential responses to drugs and environmental stimuli. Mechanisms underlying the formation of CNVs also provide insight into evolutionary processes and human origins.
Using microarray technology, scientists can scan for CNVs across the genome in a single experiment. While this is a cost-effective means of obtaining large amounts of data, scientists have struggled to accurately determine CNV copy number and to precisely define the boundaries of CNVs in the genome. Two papers published today in Genome Research present groundbreaking approaches to address these issues.
One paper describes a new whole-genome tiling path microarray, which was constructed from the same DNA used to sequence the human genome in 2001. The array covers 93.7% of the euchromatic (gene-containing) regions of the human genome and substantially improves resolution over previous arrays. The array was employed in a process known as comparative genomic hybridization (CGH), which involves tagging genomic DNA from two individuals and then co-hybridizing it to the array. Data from the array were assessed with a new algorithmic tool, called CNVfinder, which accurately and reliably identified CNVs in the human genome.
"This method helped us to develop the first comprehensive map of structural variation in the human genome," says Dr. Nigel Carter, one of the lead investigators on the project. "We used it to help identify 1,447 CNVs, which covered 12% of the human genome."
The other paper presents a new multi-step algorithm used with the Affymetrix GeneChip® Human Mapping 500K Early Access SNP arrays. The specificity of the algorithm, coupled with the increased probe density of these arrays, permitted the identification of approximately 1,000 CNVs, many of which were below the detection size limit of alternative methodologies. Furthermore, the algorithm more accurately estimated CNV boundaries, thereby permitting a detailed comparison with other genomic features.
"This new approach will be useful in understanding the role of CNVs in disease pathology--not only copy number changes in cancer cells, but also possible association of CNVs with common diseases," explains Dr. Hiroyuki Aburatani, one of the scientists who led the development of the algorithm. "We'll be able to develop diagnostic tests with sub-microscopic resolution, and because the analysis detects SNPs--single-nucleotide polymorphisms--in addition to CNVs, it will find widespread use among researchers performing disease-association studies."
Maria A. Smit | EurekAlert!
Cancer diagnosis: no more needles?
25.05.2018 | Christian-Albrechts-Universität zu Kiel
Less is more? Gene switch for healthy aging found
25.05.2018 | Leibniz-Institut für Alternsforschung - Fritz-Lipmann-Institut e.V. (FLI)
The more electronics steer, accelerate and brake cars, the more important it is to protect them against cyber-attacks. That is why 15 partners from industry and academia will work together over the next three years on new approaches to IT security in self-driving cars. The joint project goes by the name Security For Connected, Autonomous Cars (SecForCARs) and has funding of €7.2 million from the German Federal Ministry of Education and Research. Infineon is leading the project.
Vehicles already offer diverse communication interfaces and more and more automated functions, such as distance and lane-keeping assist systems. At the same...
A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.
The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...
At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.
At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...
There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?
At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...
So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics
Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...
25.05.2018 | Event News
02.05.2018 | Event News
13.04.2018 | Event News
25.05.2018 | Event News
25.05.2018 | Machine Engineering
25.05.2018 | Life Sciences