Predicting and testing physical locations of
genetically mapped loci on tomato pachytene chromosome 1
Song-Bin Chang 1, Lorinda K. Anderson 2, Jamie D. Sherman 3, Suzanne M. Royer 2 and Stephen M. Stack 2*
1 National Taiwan University
2 Colorado State University
3 Montana State University
* To whom correspondence should be addressed. E-mail: sstack{at}lamar.colostate.edu.
Submitted on April 3, 2007
Revised on May 7, 2007
Accepted on 23 May 2007
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Abstract |
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Predicting the chromosomal location of mapped markers has been difficult because linkage maps do not reveal differences in crossover frequencies along the physical structure of chromosomes. Here we combine a physical crossover map based on the distribution of recombination nodules (RNs) on Solanum lycopersicum (tomato) synaptonemal complex 1 with a molecular genetic linkage map from the interspecific hybrid S. lycopersicum X S. pennellii to predict the physical locations of 17 mapped loci on tomato pachytene chromosome 1. Except for one marker located in heterochromatin, the predicted locations agree well with the observed locations determined by fluorescence in situ hybridization (FISH). One advantage of this approach is that once the RN distribution has been determined, the chromosomal location of any mapped locus (current or future) can be predicted with a high level of confidence.
Key Words:
fluorescence in situ hybridization, linkage maps, pachytene chromosomes, recombination nodules, tomato
