Genetics, Vol. 166, 947-957, February 2004, Copyright © 2004
Meiotic Recombination Between Paralogous RBCSB Genes on Sister Chromatids of Arabidopsis thaliana
John G. Jeleskoa,
Kristy Cartera,
Whitney Thompsona,
Yuki Kinoshitab, and
Wilhelm Gruissemc
a Plant Pathology, Physiology, and Weed Science Department, Fralin Biotechnology Center, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061-0346,
b National Institute of Genetics, Agricultural Genetics, Mishima, Shizuoka, 411-8540, Japan
c Institute of Plant Sciences, Swiss Federal Institute of Technology, ETH Zentrum, CH-8092, Zurich, Switzerland
Corresponding author:
John G. Jelesko, Virginia Polytechnic Institute and State University, West Campus Dr., Blacksburg, VA 24061-0346., jelesko{at}vt.edu (E-mail)
Communicating editor: B. BARTEL
Paralogous genes organized as a gene cluster can rapidly evolve by recombination between misaligned paralogs during meiosis, leading to duplications, deletions, and novel chimeric genes. To model unequal recombination within a specific gene cluster, we utilized a synthetic RBCSB gene cluster to isolate recombinant chimeric genes resulting from meiotic recombination between paralogous genes on sister chromatids. Several F1 populations hemizygous for the synthRBCSB1 gene cluster gave rise to Luc+ F2 plants at frequencies ranging from 1 to 3 x 10-6. A nonuniform distribution of recombination resolution sites resulted in the biased formation of recombinant RBCS3B/1B::LUC genes with nonchimeric exons. The positioning of approximately half of the mapped resolution sites was effectively modeled by the fractional length of identical DNA sequences. In contrast, the other mapped resolution sites fit an alternative model in which recombination resolution was stimulated by an abrupt transition from a region of relatively high sequence similarity to a region of low sequence similarity. Thus, unequal recombination between paralogous RBCSB genes on sister chromatids created an allelic series of novel chimeric genes that effectively resulted in the diversification rather than the homogenization of the synthRBCSB1 gene cluster.
