Genetic Priming

John Jacob Lyons is an independent socio-evolutionary psychologist and evolutionary theorist working in London, U.K. He has suggested the hypothesis known as 'Genetic Priming'. This explains how, over evolutionary time, learned adaptive behaviour of living organisms tends to prime their genome to favour gene-variants that support/encourage that behaviour; needing just a simple environmental 'trigger' for the behaviour to be manifested. He has suggested that 'niche construction' in animals, such as nest-building in birds and the web-building of spiders as well as many aspects of human behaviour, such as language and religiosity, have been subject to the Genetic Priming mechanism.
Learned adaptive behaviour is invariably positively correlated with particular genetically-mediated propensities/predispositions. The preferential selection of the adaptive behaviour of organisms will cause the gene variants of these associated propensities/ predispositions to become more frequent in the following generation. This will result in greater numbers of organisms being genetically primed to express the adaptive behaviour in that generation and actually manifesting it. In turn, this will mean that the associated gene variants will again increase in frequency in the next generation. Thus a positive inter-generational feedback loop is created. Over evolutionary time all organisms in the species will be genetically primed to express the adaptive behaviour; needing just a simple environmental trigger for the behaviour to be manifested. There may well be more than one adaptive behaviour 'trying' to prime the same or an overlapping set of gene variants concurrently. This would result in the genetic priming, for any particular adaptive behaviour, being rather less than optimal.
The alternative theory known as the Baldwin effect proposes that consistent adaptive behaviour results in selection pressure for a general learning ability and results in the assimilation of the character or trait change. The precise mechanism that produces this assimilation is not specified and no environmental 'trigger' is proposed by this theory. Genetic Priming should not be confused with the phenotypic plasticity/epigenetic processes (such as methylation and chromatin marking) that enable an organism to adapt to environmental changes experienced during its lifetime and to pass on these adaptations to subsequent offspring.
There was a study carried out in 1967 on the neo-natal pecking behaviour of chicks that was relevant to and confirmatory of Genetic Priming. They would only peck at "shiny, high contrast targets". In particular, they would peck at their own toes until, by chance, they hit upon food/water. This 'environmental experience/trigger' was found to be necessary before they pecked only at the food/water and not their own toes. If their toes were masked, and no other shiny targets were available, they didn't peck at all. From the viewpoint of the much more recent Genetic Priming hypothesis, the chicks appear to have been genetically primed to peck at shiny objects but needed an environmental trigger to peck only at food/water.

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