Category: Genetic diversity

Rebsie Fairholm at Daughter of the Soil has a long post about Association Kokopelli, the French outfit fined for unfair practices because they dared to sell seeds of varieties that their customers actually wanted. ((In some small way I prompted the post, which is nice.)) Rebsie gives some of the history and some of the delights of Association Kokopelli, and suggests various ways in which people can support them. She also raises the spectre of Kokopelli going under again, and of the many varieties they have and make available going extinct.

People who have varieties from Kokopelli can certainly swap them, as suggested. But I’m wondering about a couple of other ideas. First, is there any chance that the Global Seed Vault in Svalbard would accept a black box safety duplicate collection from Kokopelli? Possibly not. But then, what is the extent of duplication between Kokopelli’s list and the list of Seed Savers Exchange. I have no idea. But I do know that SSE’s list is fully computerized, and I would hope that Kokopelli’s is too. First order of business, then, would be to ensure that SSE has all of Kokopelli’s material.

Of course, names are a tad tricky. They always are. Rebsie asks, “Where else but Association Kokopelli can you get Venus’ Nipple tomatoes?”. That depends. Might Venus’ Nipple be the same as Teton de Venus? I doubt it, but you never know. Here in Italy a breast is often una tetta. Not too far from that to Teton. Or is it? Ot it might be plain Venus, which in Europe is available at Vent Marin. And I found that through Tomodori, which seems to aggregate tomato seed offerings from around the web.

One of the beauties of SSE is that seed savers and gardeners can use the autumn catalog to order direct from one another. What makes this possible is the size of the catchment area. The vast majority of SSE members live in the US, and they can use US postage stamps to send out their seeds. That makes life very simple. Europe needs a postal union to make a continent-wide exchange workable. Until then, all we can do is encourage gardeners and seed savers everywhere to swap varieties, keep good records and, in Rebsie’s words:

Sow your heirloom seeds with pride and raise two fingers to the EU seed legislation and the big bloated corporations who feed off it.

P.S. In other heirloom news, Chef Robert shares his love of raddichio, while Rebecca Pastor continues Becky and the Beanstock, an examination of heirloom beans.

P:P:S: Olives and Artichokes, a blog by some transplants from Wales to southwest France, also comments on Kokopelli.

Are populations on the edge of the geographic range of a species not so important to conserve as more central ones? That’s the provocative question tackled by a recent meta-analysis. (( ECKERT, C.G., SAMIS, K.E., LOUGHEED, S.C. (2008). Genetic variation across species’ geographical ranges: the central-marginal hypothesis and beyond. Molecular Ecology, 17 (5), 1170-1188. DOI: 10.1111/j.1365-294X.2007.03659.x)) Theory would suggest that marginal populations should be less diverse, and therefore possibly of less conservation value. But the theory has never really been properly tested, so the common assumption that marginal populations are less diverse is just that — an assumption.

Its theoretical underpinning is that individuals and populations are likely to be fewer and more widely spaced on the periphery compared to the centre of the range of a species. That means that effective population sizes are likely to be lower and isolation more pronounced, which suggests that genetic diversity within populations should be lower and among populations (differentiation) higher in marginal areas.

That turns out to be more or less the case for the 134 population genetic studies (of both plants and animals) reviewed by the authors: “any given species is more than twice as likely to show the predicted pattern as not, and usually a change in diversity is accompanied by a parallel change in differentiation.”

There are some caveats, however. The differences were generally pretty small. The actual mechanisms producing them not clear (were the differences the legacy of historical environmental changes or the result of ongoing evolution?). The sampling of species was biased taxonomically and geographically. Plus all of the studies looked at (supposedly) neutral variation rather than traits which might actually have adaptive importance.

But the results are nevertheless intriguing. Especially when you think about how they might be different for crops (I don’t think any of the 134 studies reviewed were of domesticated species). If anything, one would predict geneflow from the center to the periphery, and indeed among peripheral populations, to be stronger in crops than in wild species. That means that differences in genetic diversity and differentiation between centre and periphery are likely to be even smaller, maybe non-existent. Sounds like something worth checking.