Table 2. Frequency of defined trinucleotides of decoy 3′ splice sites in candidate In100 elements (numbers observed and expected for introns/exons).

	CAG		AAG		GAG		TAG		Total
	Intronic	Exonic	Intronic	Exonic	Intronic	Exonic	Intronic	Exonic	Intronic	Exonic
Obs No.	4277	65	4643	95	3814	57	5126	80	17860	297
Exp No.	3572	73	5001	77	3750	74	5537	73	17860	297
Excess (O-E/E)×100	19.7	−11	−7.2	23	1.7	−23	−7.4	10
(O-E)2/E	139.1	0.877	25.6	4.21	1.1	3.9	30.5	0.67	196.3	9.7

χ² = 196.3 for df = 3 indicates a probability that is very low (P = 4.2×10⁻⁴²), thus there is a significant excess (∼20%) of the In100 element candidate as defined by CAG at the last three positions of the decoy 3′ splice site inside the In100-like elements located in introns. The opposite pattern is observed for CAG inside the In100-like elements located in exons: depletion of 11% (X² = 9.7 for df = 3; P = 0.021). The expected numbers were calculated separately by the nucleotide composition of intronic regions: 0.28 for A, 0.31 for T, 0.20 for C and 0.21 for G; and of exonic regions: 0.258 for A, 0.246 for T, 0.246 for C and 0.25 for G [43].