Category: Livestock

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Pussy Galore

A paper appeared in Science last year which used mitochondrial DNA and microsatellites to determine the geographic origin of the domesticated cat. We blogged about it back in June, albeit briefly. The major conclusion was that the cat was domesticated once, in the Fertile Crescent, about 9000 years ago, at about the time that agriculture started to take off. A paper just out in Genomics now takes the story on from there, by looking in more detail at the relationship among pure breeds and random-bred local populations from all over the world. ((Monika J. Lipinski, Lutz Froenicke, Kathleen C. Baysac, Nicholas C. Billings, Christian M. Leutenegger, Alon M. Levy, Maria Longeri, Tirri Niini, Haydar Ozpinar, Margaret R. Slater, Niels C. Pedersen and Leslie A. Lyons. (2008) The ascent of cat breeds: Genetic evaluations of breeds and worldwide random-bred populations. Genomics 91:12-21. doi:10.1016/j.ygeno.2007.10.009))

Using microsatellites, which are best suited to resolving more recent changes in genetic diversity, the authors of this latest study tried to reconstruct what happened when domestic cats left their Middle Eastern cradle and spread all over the world, presumably with the first agriculturalists and then with merchants and other travellers. It turns out that the diversity of the genepool has not decreased much overall during the past several thousand years. But it has fragmented. So now you have quite genetically differentiated groupings among the world’s cats: in the Mediterranean, Western Europe (+ the Americas), Asia and East Africa. The Asian group is particularly interesting, being the most distinct and the one with the most internal patterning. This shows that cats went to Asia early, and became relatively isolated there, from the rest of the world and from each other. ((Don’t I remember something similar for wheat? Must look it up. Later: ok, it was barley.))

There’s interesting stuff in the paper on the relationship among pure-bred breeds. They’re apparently mostly relatively young (less that 150 years old), and there’s not really that many of them (41 are recognized by cat enthusiasts), certainly compared to dogs and livestock like cattle and sheep. And it seems they’re all derived from 16 so-called “foundation” breeds, such as the Persian, for example. These in turn mostly — there are some exceptions — originated from random-bred cats from their region of origin, i.e. Persia, in the case of the Persian. Unsurprisingly, the development of pure-bred breeds from local common-or-garden cats has been associated with a narrowing of genetic diversity. And with the accumulation of deleterious mutations. It’s only in pure-bred cats that genetic disorders have been spotted. This study should lead to better plans for breed management, that could avoid such problems, the authors hope.

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To eat or not to eat, that is the question

I don’t know much about Verlyn Klinkenbord, but I like the way he thinks:

Anyone who really cares about food — its different tastes, textures and delights — is more interested in diversity than uniformity. As it happens, the same is true for anyone who cares about farmers and their animals. An agricultural system that favors cloned animals has no room for farmers who farm in different ways. Cloning, you will hear advocates say, is just another way of making cows. But every other way — even using embryo transplants and artificial insemination — allows nature to shuffle the genetic deck. A clone does not.

Read the rest of his New York Times editorial — Closing the barn door after the cows have gotten out.

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Animal Genetic Resources on the ground in Uganda

A dying breed. Huge article in the New York Times magazine that looks at the general issue of disappearing livestock diversity through the particular lens of cattle in Uganda, where the local Ankhole cattle are threatened by high-yielding but fragile Holsteins. All the arguments and counter-arguments are there in a well-written piece that pulls no punches and yet, in the end, left me wondering what the solution is. Farmers who do use Holsteins profit thereby, setting off an arms race among fellow farmers, whose primary victim is the local livestock breeds. But when trouble strikes, in the form of drought or civil strife, it is the local breeds that gallop back to the rescue. As long as they remain alive …