The .gtf file contains MVP mapping data for the Human Epigenome Project (HEP) in the format described below.

Data are arranged in 10 columns as follows:

Column	Date type	Values in HEP1_data.gtf
1	feature_class	ESME
2	identity	(unique, see below)
3	type	CpG
4	sub-type	Analysis, Trace, Variation
5	chromosome	6, 20, 22
6	chr_start	base position
7	chr_end	base position
8	orientation	+
9	phase	.
10	methylation score	0-100 . = 'no data' -1 = 'data not analysed'

Column 2 may be decoded thus:

for CpG Trace trace_id:tissue_name
for CpG Variation trace_id:position_in_trace
for CpG Analysis Sanger:epi_id_number

The Analysis co-ordinates are those of the amplicon of the given Sanger:epi_id_number.

'CpG Variation' refers to the position of the C of each CpG.