PT  - JOURNAL ARTICLE
AU  - Yan, Honghai
AU  - Ren, Zichao
AU  - Deng, Di
AU  - Yang, Kehan
AU  - Yang, Chuang
AU  - Zhou, Pingping
AU  - Wight, Charlene
AU  - Ren, Changzhong
AU  - Peng, Yuanying
TI  - New evidence concerning the genome designations of the AC(DC) tetraploid <em>Avena</em> species
AID  - 10.1101/2020.10.02.323345
DP  - 2020 Jan 01
TA  - bioRxiv
PG  - 2020.10.02.323345
4099  - http://biorxiv.org/content/early/2020/10/02/2020.10.02.323345.short
4100  - http://biorxiv.org/content/early/2020/10/02/2020.10.02.323345.full
AB  - The tetraploid Avena species in the section Pachycarpa Baum, including A. insularis, A. maroccana, and A. murphyi, are thought to be involved in the evolution of hexaploid oats; however, their genome designations are still being debated. Repetitive DNA sequences play an important role in genome structuring and evolution, so understanding the chromosomal organization and distribution of these sequences in Avena species could provide valuable information concerning genome evolution in this genus. In this study, the chromosomal organizations and distributions of six repetitive DNA sequences (including three SSR motifs (TTC, AAC, CAG), one 5S rRNA gene fragment, and two oat A and C genome specific repeats) were investigated using non-denaturing fluorescence in situ hybridization (ND-FISH) in the three tetraploid species mentioned above and in two hexaploid oat species. Preferential distribution of the SSRs in centromeric regions was seen in the A and D genomes, whereas few signals were detected in the C genomes. Some intergenomic translocations were observed in the tetraploids; such translocations were also detected between the C and D genomes in the hexaploids. These results provide robust evidence for the presence of the D genome in all three tetraploids, strongly suggesting that the genomic constitution of these species is DC and not AC, as had been thought previously.