Eat This Newsletter 249: Selected
Hello
If farmers can select for specific traits in their livestock and crops, who’s to say that plants and animals aren’t selecting for traits in their farmers? An old trope, I know, but one that bears repeating.
Not Your Usual Potatoes
Indigenous people in the southwest of North America had more of a hand in crop domestication than is often thought, according to a new paper on the Four Corners potato, Solanum jamesii. So much so, according to the press release I read, that the results “support the [uncited] assertion that the tuber is a ‘lost sister,’ joining maize, beans and squash—commonly known as the three sisters—as a staple of crops ingeniously grown across the arid landscape”.
The release explains that populations of Four Corners potato, found, naturally enough, in the areas where Arizona, Utah, Colorado and New Mexico meet, fall into two distinct types. Some — archeological populations — grow within 300 metres of an archaeological site and are relatively small. The rest are non-archaeological and widely spread throughout the species’ range. Sampling the DNA of both types, the researchers discovered much more diversity in the non-archaeological populations than in those associated with settlements, which suggests domestication by local people.
Researchers were also able to show that specific archaeological populations were most like non-archaeological populations quite some distance away, which means that transport networks among the indigenous people were well developed. Settlement sites in the southwest of Utah were around 500 km from the nearest natural populations from which they might have been derived.
S. jamesii contains double the protein, calcium, magnesium, and iron of more familiar potatoes (S. tuberosum). The archeological populations were, however, not within the species’ central range, where the wild populations are much larger and more productive. So did people transport and grow the tubers simply to have a nourishing source of food close at hand in winter? That would be cultivation. Or were they, as seems likely, also actively selecting for things like taste, size and frost tolerance, which would put them well on the way to domestication? More detailed DNA might studies provide an answer.
A further thought. Four Corners potato, which is still grown by some Diné people (and probably others), copes well with drought and heat. Might it also have a wider market?
Milk Drinkers Are Even More of a Minority
More genetic detective work, this time on the confusing business of lactose intolerance. People who can drink milk as adults are actually a minority, around 30% globally. The notion that the inability to tolerate lactose, the sugar in milk, is somehow a deviant condition is the result, as Razib Khan explains, of the original research being done by people from northern Europe, who by and large do tolerate lactose. “[T]hey mistook the rule for the exception,” Khan writes.
That much will be familiar if you’ve listened to a few recent episodes of Eat This Podcast. The familiar story is that as they moved into Northern Europe, cattle-raising Neolithic farmers who could digest lactose — a minority to begin with — produced more offspring than those who could not and thus became a majority. The same sort of thing happened in the areas of Arabia, East Africa and northern India where most people tolerate lactose. And all this happened around 7000 years ago, in parallel with the domestication of cattle.
Khan’s piece explains that the current picture is very different.
[S]amples from individuals who died 2,000 years ago [show] that the fraction of humans who could digest milk sugar as adults in Germany then was still far lower than today; at Rome’s height, evolution was just beginning its work on this handy trait, a process that would continue into the Middle Ages and beyond.
The rest is genetics, and molecular biology, and history. The real lesson is that evolution can be very fast indeed and also that the particular mutation that underlies my lactase persistence is even more of a minority than originally thought. There are several, and probably some still waiting to be uncovered.
The Perils of Writing About Pronunciation
I love this, and had not come across it before:
I asked the maid in dulcet tone,
To order me a buttered scone,
The silly girl has been and gone,
And ordered me a buttered scone.
That’s from Punch magazine in 1913, when the pronunciation of the item at hand was already contentious. It came to light in Language Log’s report of a survey by the polling company YouGov of two fundamental questions: “gone” or “bone”, and clotted cream or jam first.
If you know anything about me, you probably know where I stand on both.
One thing neither Language Log nor the survey report identify is class. (Grass, not mass in my case, and how I wish I could write IPA). I’ve always believed that bone is associated with posh people, who take “tea and scones on the grand (demand) piano (soprano)”. At least one commenter at LL made this point, but many others just don’t understand.
Beyond the Translucent One
A treat of a read for you, if you have any interest at all in dates. The fruit, obviously.
Eric Hansen’s recounts his long search for a date he first encountered during Ramadan in a remote corner of Yemen. It's an entertaining story focused on the date industry in California, with a good deal of history thrown in, and I enjoyed it. No spoilers
Take care
.p.s. I have a bunch of notes on an aspect of the dates in America story that Hansen doesn’t mention directly. Maybe I’ll try and work those up into something, finally.
Photo of sunset from the edge of the Mogollon Rim, home of the Four Corners potato, by Coconino National Forest on flickr
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