Every Gene from a Gene. The line of thought about
genetic continuity developed thus far has described an
ever-increasing degree of precision in the generation
of living forms. Biogenesis becomes reproduction; re-
production becomes cellular; cell division becomes
mitotic; chromosomes split longitudinally, or put more
accurately, they replicate themselves, since each new
chromosome is no half-chromosome but a chromosome
entire; and finally, the substituent elements of the
chromosomes, whether visible chromatids or invisible
genes, are held likewise to replicate themselves. During
the lengthy period from about 1883 to 1953, a span
of 70 years, little was added to this particular line of
development of the concept. True, the development
of genetics made it clear that one is entitled to say:
“Every gene from a gene.” But that deduction was
made on the basis of evidence that genetic continuity
is not interrupted when cells divide, or when gametes
are formed, unite, and generate a new individual. One
could say where a gene resided in a particular chromo-
some, but not what it was. The gene and its replication
remained total abstractions.
