Darwin’s Pangenesis

The “Provisional hypothesis of pangenesis” was the name given by Charles Darwin, to provide a potential explanation on his increasing belief in the inheritance of acquired characters. Charles Darwin raise the hypothesis trying to solve the dilemma how somatic modifications could be transmitted from one generation to an other. The following passage from chapter 27 of his “Animals and Plants under Domestication” contains the entire hypothesis in a condensed form:

“It is almost universally admitted that cells, or the units of the body, propagate themselves by self-division or proliferation retaining the same nature, and ultimately becoming converted into the various tissues and substances of the body. But besides this means of increase I assume that cells, before their conversion into completely passive or “form-material,” throw off minute granules or atoms, which circulate freely throughout the system, and when supplied with proper nutriment multiply by self- division, subsequently becoming developed into cells like those from which they were derived. These granules for the sake of distinctness may be called cell-gemmules, or, as the cellular theory is not fully established, simply gemmules. They are supposed to be transmitted from the parents to the offspring, and are generally developed in the generation which immediately succeeds, but are often transmitted in a dormant state during many generations and are then developed. Their development is supposed to depend on their union with other partially developed cells or gemmules which precede them in the regular course of growth. Why I use the term union, will be seen when we discuss the direct action of pollen on the tissues of the mother plant. Gemmules are supposed to be thrown off by every cell or unit, not only during the adult state, but during all the stages of development. Lastly, I assume that the gemmules in their dormant state have a mutual affinity for each other, leading to their aggregation either into buds or into the sexual elements. Hence, speaking strictly, it is not the reproductive elements, nor the buds, which generate new organisms, but the cells themselves throughout the body. These assumptions constitute the provisional hypothesis which I have called Pangenesis.”

It is always delightful to read and discuss with students on these ancient materials -very illuminating 🙂

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