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United States Department of Agriculture

Agricultural Research Service

Title: Variation in the Ratio of Physical to Genetic Distance and Microsynteny with Rice Bacs in Intervals Adjacent to the Mla Locus on Chromosome 1h in Barley

item Descenzo, Richard
item Yu, Gong - ISU
item Wise, Roger

Submitted to: Plant Genome Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: December 13, 1995
Publication Date: N/A

Technical Abstract: Variants of pulsed-field gel electrophoresis were used in conjunction with 2-dimensional DNA gel electrophoresis (2-DDGE) to analyze lines containing recombination breakpoints in two genetically defined intervals on barley chromosome 1H. 2-DDGE analysis on parental lines demonstrated that the two loci that define the Xbcd249.1-Xbcd249.2 interval reside on a single 450-kb MluI fragment. This indicates a maximum ratio of physical to genetic distance in this interval of 1500 kb/cM as compared to the 3.7-4.2 mb/cM average for the barley genome. CHEF analysis on the adjacent Xbcd249.2-Xmwg068 interval indicates the maximum ratio of physical to genetic distance in 7.8 mb/cM. Novel high molecular weight (HMW) DNA restriction fragment length polymorphisms (RFLPs), were observed in two recombinant lines in the Xbcd249.2-Xmwg068 interval, and in three recombinant lines in the Xbcd249.1-Xbcd249.2 interval. These HMW DNA RFLPs most likely represent restriction fragments containing recombination breakpoints. Data from the recombination breakpoint analysis indicated a ratio of genetic to physical distance of 3.16 mb/cM in the Xbcd249.2-Xmwg068 interval and 0.5 mb/cM in the Xbcd249.1-Xbcd249.2 interval. Both physical linkage and recombination breakpoint analysis indicate the Xbcd249.1-Xbcd249.2 interval is approximately 6-fold smaller than the Xbcd249.2-Xmwg068 interval. Microsyntenic analysis between rice and barley utilizing sequences cloned from rice BACs will be presented.

Last Modified: 4/22/2015
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