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 half cousin, Sir 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 accepted by the great majority of scientists that Darwin was basically correct about
the theory of evolution by
natural selection.
A majority of Christians belong to churches that accept the basic tenents of the theory of evolution and it is accepted by most people in many countries which have a Christian majority and tradition. It is not so well accepted in countries with a Moslem majority.
Charles Darwin
almost certainly never saw the paper Gregor Mendel wrote. (Not many
people did.) Darwin's German was poor so he would only have read something in German that he already thought was important. If he had, it
is interesting to speculate on whether he
would have accepted it as explaining much his own Pangenisis theory did not.
Father Gregor Mendel on the other hand was well aware of Darwin's theory of evolution and approved of it.
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.
