title: Fluorescence In Situ Hybridization (FISH)-Based Karyotyping Reveals Rapid Evolution of Centromeric and Subtelomeric Repeats in Common Bean (Phaseolus vulgaris) and Relatives.
abstract: Fluorescence in situ hybridization (FISH)-based karyotyping is a powerful cytogenetics tool to study chromosome organization, behavior, and chromosome evolution. Here, we developed a FISH-based karyotyping system using a probe mixture comprised of centromeric and subtelomeric satellite repeats, 5S rDNA, and chromosome-specific BAC clones in common bean, which enables one to unambiguously distinguish all 11 chromosome pairs. Furthermore, we applied the karyotyping system to several wild relatives and landraces of common bean from two distinct gene pools, as well as other related Phaseolus species, to investigate repeat evolution in the genus Phaseolus Comparison of karyotype maps within common bean indicates that chromosomal distribution of the centromeric and subtelomeric satellite repeats is stable, whereas the copy number of the repeats was variable, indicating rapid amplification/reduction of the repeats in specific genomic regions. In Phaseolus species that diverged approximately 2-4 million yr ago, copy numbers of centromeric repeats were largely reduced or diverged, and chromosomal distributions have changed, suggesting rapid evolution of centromeric repeats. We also detected variation in the distribution pattern of subtelomeric repeats in Phaseolus species. The FISH-based karyotyping system revealed that satellite repeats are actively and rapidly evolving, forming genomic features unique to individual common bean accessions and Phaseolus species.
authors: Center for Applied Genetic Technologies, University of Georgia, Athens, Georgia 30602.
authors: Aiko
authors: 0000-0001-9378-3961
authors: A
authors: Iwata-Otsubo
authors: Department of Agronomy, Purdue University, West Lafayette, Indiana 47907.
authors: Brittany
authors: B
authors: Radke
authors: Division of Plant Sciences, National Center for Soybean Biotechnology, University of Missouri, Columbia, Missouri 65211.
authors: Seth
authors: S
authors: Findley
authors: Center for Applied Genetic Technologies, University of Georgia, Athens, Georgia 30602.
authors: Brian
authors: B
authors: Abernathy
authors: Department of Horticultural Sciences, University of Florida, Gainesville, Florida 32611.
authors: C Eduardo
authors: CE
authors: Vallejos
authors: Center for Applied Genetic Technologies, University of Georgia, Athens, Georgia 30602 sjackson@uga.edu.
authors: Scott A
authors: SA
authors: Jackson
mesh_terms: D001483:Base Sequence; D002503:Centromere / Q000235:genetics*; D004275:DNA, Ribosomal / Q000235:genetics; D019143:Evolution, Molecular; D017343:Genes, Plant; D014644:Genetic Variation; D017404:In Situ Hybridization, Fluorescence; D059785:Karyotype; D007621:Karyotyping; D027805:Phaseolus / Q000145:classification / Q000235:genetics*; D010802:Phylogeny; D012091:Repetitive Sequences, Nucleic Acid; D013045:Species Specificity
chemical_list: D004275:DNA, Ribosomal
keywords: chromosome evolution; common bean; fluorescence in situ hybridization; karyotyping; satellite repeats