Johns Hopkins Researchers Receive $1M ARRA Award to "Map Mobile DNA in Humans"
October 12, 2009-Sequencing the human genome was just one step in understanding our biology: Researchers still know very little about the function of most of our DNA. Now, a team of researchers at the Johns Hopkins University School of Medicine has been awarded $1 million in stimulus funding to examine how certain mobile segments of DNA known as transposons contribute to human genetic diversity by mapping transposon locations in more than 100 people over the next two years.
“Transposons contribute to human genetic diversity in ways we are just beginning to understand,” says Jef Boeke, Ph.D., professor of molecular biology and genetics, and director of the High Throughput Biology (HiT) Center at the Institute for Basic Biomedical Sciences at Johns Hopkins. “We hope this work will provide the basis for future research looking at how transposons affect health and disease.”
In addition to genes that code for proteins, which make up only a small fraction of our genomes, our DNA also contains so-called “junk DNA,” regulatory elements that control gene function and sequences involved in maintaining chromosome structure. Some of these regions have been difficult to sequence and are only partially included in the current human genome draft. Transposons are in this category, existing in many copies and in different places in each individual.
The teams of Boeke and Kathleen Burns, M.D., Ph.D., have developed a new method for identifying a group of these sequences, the L1(Ta) LINE (long interspersed element) transposons. Several hundred thousand LINE elements are found in the human genome, and their locations vary from one person to the next. LINE transposons can move, and depending on where in the genome they land, can change the activity of a nearby gene. These changes in gene function can in part lead to differences between people.
“We are delighted about this award,” says Burns, an assistant professor of pathology and oncology and a lead investigator on the grant. “It is a great assist in bridging the basic science of transposon biology — where Jef Boeke and his group have been major leaders — with clinical human genetics.”
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