The human gene map: a review.

Genes are mapped to human chromosomes using many different methods: by somatic cell hybridization (by far the most fruitful method until now), by taking advantage of gene dosage effect in cases of chromosomal imbalance, and more recently by molecular hybridization which consists of techniques with great potential values. Some 350 autosomal loci have been assigned. They include genetic markers (blood groups), gene clusters such as the Ig, Hb, HLA genes, enzymatic markers, hereditary diseases (the morbid anatomy of the genome), and the recently discovered "micro-deletions" responsible, for instance, of certain types of childhood malignancies. The X- and Y-linked genes are also discussed.