Table 4.

Frequency decrease of G:C→A:T after removal of CpG→TpG/CpA SNPs

Category	GC content (%)	Frequency decrease of G:C→A:T (%)
		Un-normalized	Normalized
Genome	40.0	8.8	9.7
Intergenic regions	39.4	8.2	9.2
Genes	41.0	9.7	10.4
Introns	39.7	8.8	9.7
Exons	51.7	19.4	19.2
CpG islands	62.0	12.1	11.2
Intergenic regions	<35 (31.4a)	5.7	7.1
	35–40 (37.3)	7.2	8.1
	40–45 (42.2)	9.0	9.6
	45–50 (47.2)	11.1	11.3
	50–55 (52.2)	13.0	12.8
	55–60 (57.2)	15.3	14.9
	≥ 60 (63.9)	18.2	17.4
	55–75 (60.2)b	16.6	16.0

^aThe average GC content (%) in the subcategory of intergenic regions.

^bThis GC content bin was included for the comparison with the CpG island category.