Post Author: John Jacob Lyons
In their book, “The Four Dimensions of Evolution”, the Waddington ‘canalization’ explanation of the genetic assimilation of adaptive acquired characteristics is referenced (p.262) and tacitly accepted by Eva Jablonka and her co-author, Marion Lamb. I don’t find this explanation at all convincing and want to propose my own explanation. I suggest that adaptive acquired characteristics are always positively and causally correlated with concomitant, genetically generated propensities. These propensities gradually become more prevalent in the gene-pool because of the success of the positively correlated acquired characteristic. In time, the organism will appear to be primed to acquire the adaptive characteristic. It is suggested that examples in humans are language and religion.
Suppose that a particular mutation (M) that appears at generation n increases the capacity to learn an adaptive behaviour (AB). AB will have a selective advantage and consequently the relative frequency of M in the population will increase in generation n+1. This will, in turn, increase the frequency of AB in this generation. So long as AB remains adaptive, this positive feedback loop will, over evolutionary time, lead to all organisms in the population having mutation M and exhibiting adaptive behaviour AB. Additionally, selective pressure will result in AB appearing earlier and earlier in the lifetime of organisms. In due course, it will appear that all organisms in the species are primed to acquire the AB.
As stated, I believe that two examples of this process in humans are language and religion. This would account for the innate ‘Language Acquisition Device’ hypothesized by Noam Chomsky and Precocious Religious Belief hypothesized and empirically demonstrated by, among others, Justin Barrett (Centre for Anthropology and Mind, Oxford University). I don’t believe that an adaptive acquired characteristic is ever genetically assimilated as proposed by Waddington. In other words, I don’t accept that the Weismann Barrier between somatic and germ cells is ever crossed in these circumstances. Rather it is as if the constituents of the genetic soil, as it were, are gradually optimized to promote the germination and growth of the AB seed. In the case of religion, the seed of belief/ faith may be provided by the parent explaining to the child that their sadly expired pet kitten, Tiddles, is now “with god in heaven” and reinforced by similar references later on. In language, the innate universal grammar proposed by Chomsky and others, may be characterized in a similar way with the heard phonemes, words, syntax and grammatical exceptions of the native language providing the seeds.
It is also suggested that the niche construction and extensions to phenotype seen in many species of animal may also have a similar origin. These could well have originated as behaviours that proved to be adaptive and that, eventually, resulted in the concomitant, positively correlated and genetically mediated allele-sets becoming ubiquitous in the species. These would then have primed the young organism to reproduce the behaviour with minimal exposure to the behaviour by others.