Piwi-associated RNAs (piRNAs) are single strand RNA molecules ranging between ~24-32 nucleotides, specific to animals. piRNAs are inmensely diverse molecules and are expressed in hundreds of thousands. The first studies of piRNAs come from Drosophila, in which they act to silence the expression of transposable elements (TEs). It is thought that this mechanism is vital for the protection of genome integrity. Parastetoda tepidariorum is a common house spider that has been emerging as a model organism owing to its short life cycle and ease of manipulation in the lab. P. tepidariorum and D. melanogaster shared a common ancestor ~ 550 mya. P. tepidarioum has short germband segmentation. We annotate 103,123 TEs sequences in P. tepidariorum genome using RepeatMasker, which represent 0.96% of the genome. We identify that the total piRNAs exhibit uracil bias at the first nucleotide position and the small proportion of piRNA exhibit the adenine at the tenth nucleotide position. We identified abundant piRNAs. The ping-pong signature was present in piRNA transcribed from TE and protein sequences.
- miRNA, piRNA, genome duplication, embryogenesis, Parasteatoda tepidariorum