Monday, January 22, 2018


Experimentally tamed fox created by in-breeding


This study identifies and analyzes statistically significant overlaps between selective sweep screens in anatomically modern humans and several domesticated species. The results obtained suggest that (paleo-)genomic data can be exploited to complement the fossil record and support the idea of self-domestication in Homo sapiens, a process that likely intensified as our species populated its niche. Our analysis lends support to attempts to capture the “domestication syndrome” in terms of alterations to certain signaling pathways and cell lineages, such as the neural crest.

The paragraph quoted above is a good example of research jargon that most of us never tried to understand until Google came along and offered the opportunity, the access.  In fact, some of us turned out to be so interested that the scientific journals that made their profit by publishing such material behind “paywalls” were slowly pushed aside by “open access” online journals, unexpurgated by experts.  This is both dangerous and rewarding.

Vocabulary is a problem.  What I get here is that a “sweep screen” is a collection of data accessible on the Internet, which is a common commercial practice to find out who buys which toothpaste or might watch which movies.  In this case the idea is to discover statistical genetic links to a specific cultural development.  We’ve all been curious to know when in hominin cultural history the fossil record supports the advent of fire technology or “art” or funerary practices.  Geneticists would like to think that this meant enabling changes in gene-supported abilities, like FOXP2, not the animal but " a protein that, in humans, is encoded by the FOXP2 gene, also known as CAGH44, SPCH1 or TNRC10, and is required for proper development of speech and language."

It’s a little different to consider a “domestication syndrome”.  The genes necessary for handling language have been identified, mostly by trying to help people who never develop speech, and the difference between a wild species of cow and the domestic version are pretty clear.  But can that notion be slid over onto humans?  I haven’t even run across a study of the genetic difference between a wild dog and a domestic pet.  (They probably exist.)  

Maybe the difference is not in the essential understructure of molecules at all — maybe it’s in the process of enculturation.  Certainly, after years of watching this local cat population, I see the same mother cats produce both wild and domesticated cats.  That is, if "domestic" is defined as human-interacting, domicile-sharing, food-dependent animals.  But there are several points along a continuum between cats totally committed to humans and those completely separated, maybe even unaware of humans.  Both are genetically programmed to have predator behavior, but it may be channeled different ways.

“Satellite” cats come and go around humans, depending on other food sources.  A supply of mice means no need for kibble. Some desert species are so elusively nocturnal that  in order to see them live people can only set up camera traps.  “Stray” cats are not usually “straying” at all, but have ranges and hunting patterns that go in and out of human structures, like alleys.  “Feral” cats are technically cats that were once owned, but now go wild, but many of the cats I know have never been owned at all except by mother cats.

It’s clear that animals have culture — not just chimps who have learned to use sticks or monkeys who have learned to take yams into water to wash them, but behavior and reactions learned from adults while maturing.  And it seems that an animal that has a “home” burrow and range is “domestic” on its own terms.”  Animals are hunter/gatherers and capable of recreating their dwelling as necessary.  

The arc of development to maturity means starting with total dependence on the mother for food, protection, location, and then circling out farther and farther to total independence, esp. in the case of males.  Humans can also develop this way, particularly if the home becomes hostile when a male child matures enough to be a threat.  Then he’s driven off.

But another genetically controlled aspect of domestication is the establishment of households, groups that might or might not be related. These groups, through cooperation that allows some specialization or at least alternation of service to the whole, can support evolution and a wider range of behaviors.  Thus, pack animals like wolves or herds like elk can survive better.

The study we’re looking at here is not just investigating modern humans where behavior could be observed, various and confusing as it is, but also trying to spot this “domestication syndrome” which is entirely thought-defined, a “concept”, a generalization.  What IS domestication in humans as distinguished from, say, a pride of lions?  And is there a genetic connection that can be defined?  Or is it emotional?  Are emotions genetically defined?

This idea of “self-domestication” based on genetics seems to be driven in part by the results of an inbreeding program with foxes.  As in animal husbandry, the most friendly and human tolerant cubs were bred to each other while the skittish or hostile ones were discarded.  Over time the foxes not only became “tame” but also showed changes in their physical development.  Domesticated species display a range of anatomical and behavioral phenotypes that set them apart from their wild counterparts: depigmentation; floppy, reduced ears; shorter muzzles; curly tails; smaller teeth; smaller cranial capacities (and concomitant brain size reduction); paedomorphosis; neotenous (juvenile) behavior; reduction of sexual dimorphism (feminization); docility; and more frequent estrous cycles.”

The idea is that the difference between Neanderthals and modern humans is comparable, that we became modern by becoming “tame,” domestic.  The claim is that there are 41 identified genes involved in this change for modern humans.  We don’t have much complete DNA info for Neanderthals — the scientists even thoughtfully include Denisovans -- but none of the other hominin versions.  Clearly, these scientists are trying to find the line between the more “civiized” and achieving people and those who are relatively unevolved.  The old Aryan search revives: who among us is naturally worthier than the others?  Who are Elves and who are Orcs?  Class hierarchy just won’t go away.

As well, the recent lamented “Middle Class” with their Brit gentry markers of upscale success (elaborate and well-defended homes, fancy foods, expensive clothes, powerful vehicles, exotic travel, and PBS shows about royalty) wants to think that their privileged status (compared to refugees) is due to innate merit and conscientious effort.  Therefore, if they are “domesticated” (which is a high Victorian value) as opposed to “wild” (which is basically uncontrolled by the domesticated) then it’s only because they earned it.  

In a time when any domiciles can be suddenly swept away by fire, flood, economics, and stock market failures, this reassuring idea has a lot of appeal.  The truth of it is more elusive.  I doubt domesticity is genetic at all.  Possibly it lies with the “wild” ability to recreate a home, as necessity demands for survival.

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