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A comparative cytogenetic study of 17 Avena species using Am1 and (GAA)6 oligonucleotide FISH probes

Luo, Xiaomei, Tinker, Nick A., Zhou, Yonghong, Liu, Juncheng, Wan, Wenlin, Chen, Liang
Acta physiologiae plantarum 2018 v.40 no.8 pp. 145
Avena (Poaceae), diploidy, fluorescence in situ hybridization, genome, genomics, hexaploidy, loci, nucleotide sequences, oligonucleotide probes, oligonucleotides, tetraploidy
Fluorescence in situ hybridization (FISH) was performed to explore the genomic and species relationships among 17 taxa using Am1 (oligo-Am1) and (GAA)₆ oligonucleotide probes. Oligo-Am1 (51 bp) hybridized strongly over almost the entire length of all chromosomes in the C genome. Six translocations between the A and C genomes were found in AACC tetraploids and AACCDD hexaploids, four minor translocations between the C and D genomes were found in AACCDD hexaploids, and two large translocations between the C and D genomes were found in A. sativa. In the 17 Avena species, (GAA)₆ regions mainly appear as sharp, thin bands at pericentromeric positions in the A, B, and C genomes and at termini in the B genome. However, no (GAA)₆ signal loci were observed in the D genome. The (GAA)₆ signal number was constant in both AA and CC diploids, though with different signal intensities. The (GAA)₆ signal pattern was diverse in AABB, AACC, and AACCDD polyploids, with each species exhibiting one signal pattern. The (GAA)₆ signal number was consistent in diploids and varied in polyploids, describing an intragenomic relationship among Avena species. This study is the first to test these two oligonucleotides, which are based on synthesized repeat units (18–51 bp), in the genus Avena. Our approach paves the way for future studies in which FISH probes can be used to assign other landmark genomic sequence oligonucleotides to physical chromosomes.