Characterization and transcriptional analysis of a subtelomeric satellite DNA family in the ladybird beetle Henosepilachna argus (Coleoptera: Coccinellidae)

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Satellite DNAs are the major repetitive components in eukaryotic genomes. Although satellite has long been called parasite DNA there is substantial evidence that it could be associated with some functions of chromosome biology. Ladybird beetles (Coccinellidae) are one of the largest and most important groups of beetles. Many ladybirds are of economic interest as biological control agents because they eat some agricultural pests such as aphids and scale insects. However, other species are phytophagous and can damage crops. Despite the ecological importance of the latter group there are no studies on their satellite DNA. A satellite family was isolated and characterized in the ladybird Henosepilachna argus. This satellite is organized in tandem repeats of 658 bp and is A + T rich (67.3%). The recorded high sequence conservation of the monomers together with the detection of putative gene conversion processes indicate concerted evolution. Reverse transcription polymerase chain reaction (RT-PCR) revealed that this satellite is transcribed and in situ hybridization its location in the subtelomeric regions of all chromosomes except the long arm of the X chromosome. The presence of this satellite in other species of the genus Henosepilachna and Epilachna was also tested using PCR. The results indicate that this satellite sequence is so far specific to H. argus.