Cats: they would be assimilated

Asian wild cat
Asian wild cat

There is a paper in PNAS, Earliest evidence for commensal processes of cat domestication, which raises some interesting questions about the emergence of Felis silvestris catus, the domestic cat. I state questions, because the answers it provides are quite narrow, if plausible. In sum the authors found that ~5,000 years ago a group of cats, possibly Asian wildcats, Felis silvestris ornata, seem to have entered into coexistent relationship with humans. This itself is not entirely surprising. ~10,000 years ago a specimen of Felis silvestris lybica, a Near Eastern wildcat, seems to have been interred at a human grave site on Cyprus. The PNAS paper correctly notes that mitochondrial data also point to Near Easter wildcats has being the wild silvestris group that gave rise to the domestics. Strangely they leave out that autosomal microsatellites, highly variable repetitive regions in the genome, also indicate a clustering of domestic lineages with Near Eastern wildcats (to be clear, this is in the same paper that they cite for the mitochondrial results).

A confluence of results, phylogenetic, phylogeographical, archaeological and morphological, do seem to support the proposition that catus and lybica form a monophyletic clade (or, perhaps more precisely catus is a derived branch of lybica). I won’t put 100% confidence on this, but that’s our best guess. So where do these Chinese results fit into the big picture? You can imagine how the media have reacted. Here’s the marginally staid (by British standards) The Guardian: Ancient Chinese cat bones shake up domestication theory.

Actually there’s that much domestication theory to shake up. The term “domestication” is genuinely problematic in a precise sense, in that it isn’t a precise term. There is a live debate as to whether domestic cats are genuine domestics, whatever that means. Setting this non-trivial semantic aspect of the debate aside, to my knowledge there is no strong genetic evidence that East Asian domestic cats exhibit any signs of deep ancient population structure. That is, that they derive from hybridizations of western and eastern silvestris lineages. That doesn’t mean that it can’t happen. The popular Bengal breed was developed in the past few decades by hybridization domestic cats with Asian leopard cats, which aren’t even in the genus Felis (though the ones adopted out are usually F4 individuals and the product of backcrosses with domestics). But we don’t have widespread evidence of hybridization, though the geographical coverage and marker density leave something to be desired (yes, I’m hedging here, but that’s what the data are telling us).

So then the Chinese cats who coexisted with humans are a “false dawn” of domestication? Perhaps a dead end? If you view them in isolation, perhaps. But they shouldn’t be. Rather, they are another datum in a sequence of results which implies that the “Anthropocene” has been characterized by humans refashioning their environment so that a range of other organisms enter into coexistent, and sometimes domestic, relations with them. The domestication of dogs and cattle seem rather complex affairs, and may have had multiple starts, stops, and dry runs. The coexistence of some small (or, if you are a Drosophila geneticist, megafaunal) metazoans with humans as they began to co-opt a larger fraction of the earth’s biosphere should be no surprise. Instead of one single domestication it is possible that many organisms had multiple domestications, even if in many cases only a single event leaves a genetic traces today. That’s because domestication is a selective event, and works with the phylogenetic variation which is available to it. That variation is often wide enough that different lineages may develop “domestic” morphs rather readily. That may be what was happening in East Asia before the extant catus populations overwhelmed the nascent oranta derived domesticates.

Citation: Earliest evidence for commensal processes of cat domestication.

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