Last August and September we discussed an idea that I brought up when I wondered if propensity for having a religion was inherited. I speculated that there might be a genetic basis for adopting the popular religions such as Christianity, Judaism, Catholicism, Islam and even Mormonism among others. I was inspired to discuss this by an OpEd in the NYTimes entitled “On the Trail of Inherited Memories.” The author traced such memories that she could not explain back to Andalusian Spain to explain the religious practices of her family from the Spanish Incquisition through the generations to today. I have always wondered if the survival of Christianity and the other long lived religions is actually instinctual and encoded in our DNA. Likewise, I have wondered if tendencies that lead us to become Democrats or Republicans and perhaps liberals or conservatives are encoded in our DNA. It is reasonable to believe that instinctual memory is encoded in our DNA because these instincts are inherited. As Diane inferred, it’s hard to imagine and actual gene encoding an instinct to which I pointed out that the genetic basis could be encoded in extra-genic DNA. Only today did I discover a break-through on the genetic basis of instinct, e.g. inherited memory.
Hopi Hoekstra, an evolutionary biologist at Harvard, published a paper in Nature on January 16th that was written up in the NYTimes today. For the first time to my knowledge, she has identified four genetic loci in a species of mouse,”oldfield mice (Peromyscus polionotus) (that) build complex burrows with long entrance and escape tunnels, and that burrow length is consistent across populations.” … “This burrow architecture is in contrast with the small, simple burrows of its sister species, deer mice (P. maniculatus).” … “Quantitative trait locus analysis … indicates that tunnel length segregates as a complex trait, affected by at least three independent genetic regions (loci), whereas the presence of an escape tunnel is associated with only a single (genetic) locus.”
I think this is the first time that mammalian instinctual behavior in one species of mouse (an oldfield mouse) has been genetically defined by comparison with another mouse species (a deer mouse) that has a different instinctual behavior. This is a demonstration of how two species of mice can evolve from a common ancester due to DNA sequence difference (caused by mutations) that govern the two distinct behaviors of the oldfield mouse and the deer mouse.
To define the actual changes in the DNA governing these two distinct instinctual behaviors, she will have to clone these DNA loci. This can be done. Whether or not these DNA loci will be in exons (coding sequences that encode proteins) or in DNA sequences outside of the coding regions will be interesting to learn and will serve as a model for inherited extinctual memory in mammals. If this is proved to exist in mice then it’s a forgone conclusion that it exists in humans.