Physical localization of rDNAs and microsatellite sequences on the chromosomes of Lactuca saligna using fluorescence in situ hybridization

• Published in: Chromosome Science Vol. 22; no. 1-4; pp. 13 - 18
• Main Authors: Widarmi, Winny Dewi, Kikuchi, Shinji, Sassa, Hidenori, Koba, Takato
• Format: Journal Article
• Language: English
• Published: THE SOCIETY OF CHROMOSOME RESEARCH 2019
• Subjects: FISH; L. saligna; microsatellites; rDNAs
• ISSN: 1344-1051; 2185-0852
• DOI: 10.11352/scr.22.13

Lactuca saligna L. is one of the wild species in the genus Lactuca and is considered to be the most important genetic resources in the lettuce genepool. In the present study, fluorescence in situ hybridization (FISH) was applied to localize 45S and 5S rDNA sequences and nine microsatellites on mitotic, and meiotic diakinesis and pachytene chromosomes of L. saligna. FISH using 45S and 5S rDNAs as the probes provided high resolution FISH images. Insertion of 5S rDNA into the region of 45S rDNA was also found on Chromosome 5. This is the first report of high-resolution FISH with 45S and 5S rDNAs on pachytene chromosomes of L. saligna. Of the nine microsatellite probes tested, (AAC) 7, (ACG) 7, (CAC) 7, and (CG) 10 yielded no signals. The other five microsatellite probes, (AG) 10, (AC) 10, (GCC) 7, (ACT) 7, and (AAG) 7 successfully produced FISH signals. The signals of (AG) n, (AC) n, and (GCC) n were found to be distributed across the prometaphase chromosomes. In contrast, the signals of (ACT) n and (AAG) n showed chromosome specific patterns, indicating these signals could be used as chromosomal markers of L. saligna. Our FISH images using rDNAs and microsatellites as the probes provided valuable information for discrimination of chromosomes in L.saligna, and it would be beneficial for future cytogenetic studies on Lactuca genomes.