How to get a unknown gene site and its sequence.

[mloonjin]

now I meet some trouble.I know a gene locate a chromosome,and the chromosome have the only one gene.the chromosome length is about 14MB.and most sequence is SSR.so it's not realistic to get the sequecne by bird-gun method.whether exist other method can get the gene.It's quite difficult to set genetic experiment because there isn't the any tother phenotypic marker in the chromosome .the unique gene is the unknow gene.and the gene dominate an phenotype.I don't know how to get their sequence.How to design an experimet for that.
thank you for your suggestion.