mature cells making up all the parts of the adult animal. Thus, skin cells, blood cells, organ cells are
differentiated cells.
In its ordinary meaning, totipotency refers to cells which are unrestricted in their
developmental capability. Such cells have the ability through cell division and multiplication to
differentiate into any and all parts of the adult animal. In normal animal development, totipotent
cells exist only in the early development stages of an organism - principally in the zygotic and early
embryonic phases. Differentiated cells are no longer totipotent in that subsequent generations of
cells are not unrestricted in their developmental capacity. Once a differentiated cell forms,
subsequent generations will also be differentiated. Thus, in its ordinary meaning, totipotent cells are
undifferentiated cells. In other words, in the ordinary meaning to those working in the art, totipotent
cells are not differentiated cells.
The cells of an organism may also be characterized into two categories: somatic cells and
germ line cells. Germ line cells are cells from which the next generation of gametes - the sperm and
ovurn- may be derived. The gametes are the cells which pass genetic information onto the next
generation of the organism. Somatic cells are non-germ line cells. In other words, somatic cells are
any cell other than a germ cell or germ cell precursor." In ordinary reproductive processes, somatic
cells do not pass genetic information on to the next generation of the animal. Totipotent cells, which
may develop into all the cells of the adult organism, including the germ cells, are germ cell
precursors and are thus part of the germ line. Thus, in its ordinary meaning, somatic cells are distinct
from totipotent cells. The two phrases refer to mutually exclusive categories.
12 Alpertsetal., Molecular Biology of the Cell, Garland Publishing Co., N.Y.& London, 1994, pp. 1012
and G-2 1. Ile parties have submitted a Joint Glossary (Paper 20) which defiries "somatic cell" as a "body cell; any cell
of multicellular organism other than gametes." We do not accept this definition as the ordinary meaning of the phrase
because it is too narrow. As support for the definition the parties cite King et at., A Dictionary of Genetics, Oxford
University Press, 1997, p. 318, which defines somatic cell as
any cell of the eukaryotic body other than those destined to become sex cells. In diploid
organisms, most somatic cells contain the 2N number of chromosomes: in tetraploid
organisms, somatic cells contain the 4N number, etc. [Emphasis added.]
The King definition does not support the parties' proffered definition since it excludes more than just the gametes. It
excludes cells which through differentiation are destined to produce gametes. Thus, the definition in King is not
inconsistent with the definition we have adopted from Alperts.
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