Sponsored by the U.S. Department of Energy Human Genome Program
Human Genome News Archive Edition
Human Genome News, July 1992; 4(2)
Investigators reported in the June issue of Genetics the development of a new genetic map comprising easy-to-use markers on each mouse chromosome [Genetics 131 (2), 423-47 (June 1992)]. This accomplishment, supported by the NIH National Center for Human Genome Research, will greatly reduce the time required to identify and isolate mouse genes implicated in polygenic diseases such as cancer, diabetes, high blood pressure, and other inherited disorders. Because of extensive and well-characterized synteny maps between mouse and human, the map will help researchers find comparable human disease genes.
The new map, which consists of 317 markers spaced evenly along the 20 pairs of mouse chromosomes, was constructed by investigators from the Massachusetts Institute of Technology (MIT) Genome Center, the Whitehead Institute for Biomedical Research, and Rockefeller University. All the work was accomplished by two researchers in less than 18 months.
The markers used to construct the new map are a type of highly repetitive DNA sequence (simple sequence repeat, or SSR) that frequently varies in length, allowing investigators to track the inheritance of genes from one generation to the next.
According to the Genetics article, the new map satisfies criteria for the ideal genetic map, which should consist of markers that are (1) abundant and evenly distributed throughout the genome, (2) highly variable among individuals, (3) easy to trace, and (4) accessible to all scientists interested in using them. Eric Lander, Director of the MIT Genome Center, explains that variability, particularly among inbred strains where genetic differences are subtle, is especially important.
"Conventional mapping techniques are extremely powerful" in following linked traits in mouse strains that vary a great deal, says Lander, but the more the strains are related through inbreeding, the more difficult it becomes to follow linked traits with conventional methods. With coauthor William Dietrich, Lander and colleagues report that analysis of crosses between two inbred mouse strains reveals differences in SSR lengths at about half the marker positions, allowing inheritance in almost any cross to be followed in a straightforward manner.
Other advantages of the new map include
Markers on the new map will be "anchored" to those on the previous linkage maps; investigators will then be able to use SSRs to locate additional genes in the region in which they have already been working. The new map will thus provide a backbone for developing a much more detailed linkage map containing as many as 3000 SSR markers.
All the markers will soon be available from
For more information on the markers, see HGN 4(1), 3 (May 1992).
For more information on the map, contact:
Reported by Eve Nichols, Whitehead Institute for Biomedical Research and Leslie Fink, Office of Communications, NIH NCHGR
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Human Genome Program, U.S. Department of Energy, Human Genome News (v4n2).
The Human Genome Project (HGP) was an international 13-year effort, 1990 to 2003. Primary goals were to discover the complete set of human genes and make them accessible for further biological study, and determine the complete sequence of DNA bases in the human genome. See Timeline for more HGP history.
Published from 1989 until 2002, this newsletter facilitated HGP communication, helped prevent duplication of research effort, and informed persons interested in genome research.