A common form of dominant mutations are neomorphs in which the regulatory
information of one gene has become associated with the coding region of
another. These are frequently associated with translocations or some
sort of transposition. Many oncogenes fall into this category.
Yet another class of dominant mutations are due to dosage effects --
where one functional copy of a gene is not sufficient to provide
the wild type phenotype (haploinsufficiency).
Keith Robison
Harvard University
Department of Cellular and Developmental Biology
Department of Genetics / HHMI
krobison at nucleus.harvard.edu