I have a batch of possible snps that I've marked in terms of base position against a NCBI refseq sequence (some of these SNP's aren't available in a public resource - so no rsID's as yet). I would like to display/plot these against the gene for that refseq cdna - perhaps in ensembl. Is this possible? I also tried using GeneomeGraphs in Bioconductor - but had problems with the intervening intron sequences - as each intron caused the base coordinates to change eg hypothetically, base 1 on refseq maps to base 1 on gene but base 50 on refseq may map to base 300 on gene as there is an intron in between! Further introns lead to more coordinate shifting.