Characteristics of selected matreshkas. Characteristics of the selected matreshkas from Fig. 4, for human (H.s.), mouse (M.m.) and rat (R.n.). Columns from left to right detail the database accessions of RefSeq transcripts used to extract matreshkas, the RefSeq description, the frame the matreshka lies in, the length in amino acids of the matreshka, whether the matreshkas start with methionine, and the number of positions where a stop codon could have occurred to interrupt the matreshka but leave the RefSeq parent unaffected.