On some biochemical aspects of regressive evolution in animals

The consideration of the zoological distribution of some high polymers, such as chitin, or of some enzymes such as chitinase, chitobiase and cellulase, leads to the conclusion that biochemical evolution can be a regressive process, in which the genes corresponding to the synthesis of a given enzyme are deleted. This regressive evolution, also called "enzymapheresis", seems to be irreversible. As is the case for morphological characteristics, regressive evolution of hydrolases appears to be consecutive to a profound adaptation of a given species or taxon to a specialized diet.