IMGT_REGIONS - IMGT V-segment regions
A list defining the boundaries of V-segment framework regions (FWRs) and complementarity determining regions (CDRs) for IMGT-gapped immunoglobulin (Ig) nucleotide sequences according to the IMGT numbering scheme.
A list with regions named one of
c("fwr1", "cdr1", "fwr2", "cdr2", "fwr3")
with values containing a numeric vector of length two defining the
c(start, end) positions of the named region.