Data for: The role of repetitive DNA in re-patterning of major rDNA clusters in Lepidoptera

Genes for major ribosomal RNAs (rDNA) are present in multiple copies
organized in tandem arrays. Number and position of rDNA loci can change
dynamically and their re-patterning is presumably driven by repetitive
sequences. We explored a peculiar rDNA organization in several
representatives of Lepidoptera with either extremely large or numerous
rDNA clusters. We combined molecular cytogenetics with analyses of second
and third generation sequencing data to show that rDNA spreads as a
transcription unit and reveal association between rDNA and various
repeats. Furthermore, we performed comparative long read analyses between
the species with derived rDNA distribution and moths with a single rDNA
locus, which is considered ancestral. Our results suggest that satellite
arrays, rather than mobile elements, facilitate homology-mediated spread
of rDNA via either integration of extrachromosomal rDNA circles or ectopic
recombination. The latter arguably better explains preferential spread of
rDNA into terminal regions of lepidopteran chromosomes as efficiency of
ectopic recombination depends on proximity of homologous sequences to
telomeres.