starlarvae

In What Darwin Got Wrong, authors Jerry Fodor and Massimo Piattelli-Palmarini discuss "master genes" that regulate multiple traits and so force those traits to evolve together. In their example, the traits regulated by a particular master gene, designated Otxi, seem unrelated to each other, but as a group the linked traits are oddly suggestive of an aquatic episode in humankind’s past. The authors write, "[. . . ] in particular, since the Otxi ‘master’ gene controls the development of the larynx, inner ear, kidneys, and external genitalia and the thickness of the cerebral cortex, selective pressures sensitive to changes in the functions of the kidneys (due to bipedal station, or different liquid intake and excretion resulting from floods or droughts), or the fixation of different sexual patterns, may have had in turn secondary effects on the expansion of the cerebral cortex and the structure and function of the larynx.” This set of traits, under the control of the same master gene, plays a foundational role in the aquatic ape hypothesis. Fluid/salt regulation (kidneys), 3D proprioceptive orientation (inner ear), breath control and speech (larynx), ventro-ventral copulation (genitals) and development of a complex cerebral cortex turn out to be fated to travel together, all being regulated by the same master gene, and all being components of the aquatic ape scenario. Certainly not conclusive, but suggestive.