piRNAs in the rat testis. A, C) Complementarity of reads derived from repeats, calculated from the 5' terminus. A) L1 transposon, C) Retroviral repeat RMER3. Dashed lines indicate randomly selected short fragments from the same region. B, D) Nucleotide content of reads on position 1 and 10 that map to loci described in A and C. E) A typical pachytene piRNA cluster contains reads derived from bidirectional transcription originating from a centrally located common point of origin. Blue: sense, red: antisense. F) Characteristics of pachytene piRNA clusters.
Linsen et al. BMC Genomics 2010 11:249 doi:10.1186/1471-2164-11-249