0074 What about genetics?

In section three, genetics enters the author’s picture of the Extended Evolutionary Synthesis.

It enters as a confounder.

0075 A confounder?

Consider the following two-level interscope.  It looks almost identical to the two-level interscope for natural history.

0076 The normal context of body development_3b brings the actuality of a phenotype_2b into relation with its genotype_1b, where the genotype expresses the potential_1b of an individual’s DNA_2a.

The question is, “Can the actuality independent of the adapting species_2a somehow influence the DNA_2a or the way that the DNA is read_1b?”

The answer is, “Yes, through natural selection_3b.”

The influence is not direct.  It is intersectional.

0077 For example, let me hypothesize that children are able to drink their mother’s milk because they produce an enzyme, called “lactase”, that is able to digest lactose, one of the sugars in mother’s milk.  As the child is weaned, the need to produce this enzyme diminishes and by adulthood, the adult cannot digest lactose, because milk is not part of the diet.

0078 So, with the above figure in mind, the phenotype changes from childhood to adulthood.  This makes perfect sense, because adults are quite different than children.

0079 Now, let me go back to the natural history version of the two-level interscopes and consider what happens when cows enter into the human household.  At first, humans protect cows and then later, humans feed cows.  That sounds like a good deal.  In effect, humans are treating cows like other humans.

0080 Cows adapt by losing their fear of humans_2b.  One would not think that this is an adaptation_2b, but it is.  Plus, other adaptations take place.  Female cows produce more milk_2b.  They do so with consistency.  The bulls, on the other hand, get culled.  So, the bull that does not ask to be culled is more likely to survive.

Here is a picture.

0081 From the humans’ point of view, humans adapt by retaining lactase production into adulthood_2b.

0082 Each adaptations entails an alteration of the phenotype, by way of intersection.

Consequently, genetics is a confounder in many discussions on niche construction.

For humans, the two-level interscope for body development_3b changes over generations to produce a phenotype of adult lactose tolerance_2b through slight changes in the way DNA_2a is read_1b.

However, changes in the genotype_1b account for the change in phenotype_2b, not the adaptation_2b.

DNA already codes for the enzyme lactase.  However, the expression of the code is regulated by proteins that lock onto the DNA.  The particular protein that locks onto the lactase site on the DNA has a range of behaviors, so selection can occur on the basis of the production of lactase into adulthood.  The adaptation_2b entails a change in phenotype_2b.  The phenoype_2b emerges from and situates the genotype_1b, that is the potential_1b of DNA_2a.  In this instance, the DNA_2a(which varies among individuals) does not need to significantly change, only the genotype_1b does.

0083 Unfortunately, biologists confound adaptation_2b and phenotype_2b even though each situation-level actuality_2b has its own normal context_3b and potential_1b.

At the same time, confusion is expected, since adaptation_2b and phenotype_2b constitute a single entity, the species.