There are currently 159323 public datasets to search.
Chromosome 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 X Y coordinate to
If you don't give coordinates (eg 200000 to 300000) you get the whole chromosome
Gene symbol
Where possible, use the official gene symbol (eg TNF) from HGNC
RefSNP number rs
Make sure you have the official rs# from dbSNP
Datasets can contain haplotypes or just genotypes, and MARKER can perform different functions on the haplotype datasets