Chile pepper domestication investigated

I haven’t read the paper on Capsicum annuum domestication by Seung-Chul Kim and colleagues in the June 2009 issue of the American Journal of Botany, but the EurekAlert piece on it is definitely intriguing. I was particularly struck by the finding that genetic differentiation between geographically distant populations is higher for the cultivated than for the wild species. That may be because people don’t move pepper seeds nearly as far as birds. Also, it seems this particular pepper should be included in the lengthening list of crops that were probably domesticated in more than one place. Need to get that pdf.

2 Replies to “Chile pepper domestication investigated”

  1. Intriguing explanation. But I wonder why the disperser birds and mammals are needed.

    If cultivated populations show higher differentation, I would guess that is because founder effects (“domestication bottlenecks”) and some selection have increased gene fixation — fixing different genes in different populations. Lots of gene flow is necessary to then decrease differentiation again. If chile cultivation started in a few locations, it first had to spread to bring the different populations in direct contact.

    Wild populations, in contrast, need not have experienced founder effects or high levels of selection, so they remain undifferentiated, even though gene flow rates may be relatively low. The rate of gene flow between the cultivated populations may be actually higher, but we would have to give the farmers and birds some more time to make the cultivated populations as undifferentiated as the wild populations.

    So what puzzle do the birds solve? Perhaps someone can send us the pdf or simply write a comment to enlighten us.

  2. Surely the point of cultivated forms is that they are differentiated. If I have a particular chile I like then the last thing I want is geneflow into my population screwing it up. Like Jacob I’m not sure I really understand the point being driven at. I would agree multiple domestications seems likely.

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