The sequence in a long chain of protein is identified by

"A major use of RFLPs is in the definition of inherited diseases in which the functional deficit is unknown. RFLPs / SNPs can be used to establish linkage groups, which in turn, by the process of chromosome walking, will eventually define the disease locus. In chromosome walking, a fragment representing one end of a long piece of DNA is used to isolate another that overlaps but extends the first. The direction of the extension is determined by restriction mapping and the procedure is repeated sequentially until the desired sequence is obtained."