It is well known that certain characteristics and certain malformations are transmitted in particular families. The hereditary potentialities which lead toward them are believed to be carried in the germ cells in minute packets called genes, which unite in the fertilized ovum and persist in each cell division, modifying the cellular physiology of the animal and directing the growth along definite lines. In addition to the potentialities of the genes directed toward normal development, there are influences outside the cell which are necessary for and affect its growth and so are able to modify the ultimate individual outcome. These surrounding or environmental factors play an important role in the development of the organism, both in the intrauterine stage and after birth. To state how much of a person's resulting physical characteristics is due to heredity and how much to environmental factors is not at present possible; it is difficult enough
WILSON JG. PRESENT STATUS OF THE PROBLEM OF OTOSCLEROSIS. Arch Otolaryngol. 1938;28(6):946–953. doi:10.1001/archotol.1938.00650040959005
Customize your JAMA Network experience by selecting one or more topics from the list below.
Create a personal account or sign in to: