The BRCA 1 and BRCA 2 genes are two genes that are sought in the genetic study of an individual in order to seek a predisposition to breast cancer (in women and also in men).
The genes of Tay-sachs, are researched in order to diagnose or eliminate Tay-sachs disease.
The first difference lies in the goal of the research: for the BRCA (screening) genes, a predisposition is sought and for the Tay-sachs genes, it is sought to confirm the disease.
The second lies in the technique used:
The first step in the study of these genes is to isolate and replicate them. The best technique for this is the PCR (polymerase chain reaction). By using primers we can amplify the gene we want. So the primers used in BRCA and Tay-Sachs research are necessarily different.