Southern blot test /suth′ərn/ , a gene analysis method used in identification of specific deoxyribonucleic acid (DNA) fragments and in diagnosis of cancers and hemoglobinopathies. It involves the placement of a nitrocellulose film on agarose gel surfaces, with dry blotting material on the film. Liquid is then transported from a reservoir beneath the gel through the gel and nitrocellulose layer. The film adsorbs the DNA fragments. The fragments are then analyzed for rearrangements in immunoglobulin or cell receptor genes, chromosomal translocations, oncogene amplifications, and point mutations within oncogenes. Immunoglobulins and T cell receptor genes bear signatures that identify various leukemias and lymphomas. See also Northern blot test.
