Pangenesis is the
theory of inheritanceCharles Darwin supported. It is often stated as
one he invented. While in the actual form he put forward this may be
so, the idea that all the parts of the body contribute to inheritance
and that the body cells shed gemmules (hypothetical particles) that go to the reproductive organs, each playing their part in the next generation was not new in Darwin's day.
The
ancient Greeks had speculated on this even before Hippocrates wrote
'Vessels for the transmission of bodily fluids are found throughout the
entire body. From every part of the body are produced particles which
mix with the bodily fluids in the vessels and are carried by them to
the testicles'.
Consequences of this theory were the cause of
some of Darwin's doubts about his theory of evolution by natural
selection. See 'Darwin's Doubts'.
Of
course not everyone at the time accepted the theory of pangenesis. One
person who tested it (with the approval of Charles Darwin) was Darwin's
own cousin, Francis Galton. Galton did experiments involving blood
transfusions in rabbits. The experiments failed to show any inheritable
characteristics being passed onto the offspring by the blood. Charles
Darwin did not accept these experiments as good evidence the theory was
wrong, and at the time there were good reasons for rejecting the
experiments.
At the same time as Charles Darwin was doing his
later work, an obscure Austrian Monk called Gregor Mendel was
experimenting with peas in a tiny monastery garden. He developed a
rival theory of inheritance, and published it in 1866. (He actually
read his paper in public the year before.)
Mendel's paper was criticized, but mostly ignored. It was cited only three times in the next thirty five years.
His
work was rediscovered about thirty five years later, and his results
duplicated and extended. Now Gregor Mendel is recognised as the Father of Genetics.
It is accepted that "Darwin was wrong about the theory of pangenisis",
while it is still being fiecely debated whether "Darwin was wrong about
the theory of evolution by natural selection".
Charles Darwin
almost certainly never saw the paper Gregor Mendel wrote. (Not many
people did.) If he had, it is interesting to speculate on whether he
would have accepted it as explaining much his own theory did not.
Charles
Darwin's theory of pangenesis is now accepted as being wrong. However,
it is a clever theory in some ways. Perhaps on some other planet there
are organisms that do have a mechanism for all parts of their body to
contribute to the offspring. This would allow for the inheritance of
acquired characteristics which could be a huge advantage.
Environmental Disasters 
