The moufflon is a wild sheep from Corsica, Sardina and Cyprus. In 1957, a male and a female from Corsica were taken to another island, this one in the southern Indian Ocean, in an attempt to establish a herd for sport hunting. The pair thrived on Haute Island, and the resulting population peaked at about 700 head in the 1970’s, thereafter oscillating between 200 and 600. Ok, so far so weird, but so what? Well it turns out that genetic diversity hasn’t behaved as expected. By rights in such a small, isolated, inbred population it should have decreased markedly as a result of genetic drift. But according to this, it hasn’t. The reason is probably strong natural selection, according to the authors of the study, who compared DNA from the original founding couple to that of the present herd.
Late blight origins
Ask anyone working in plant genetic resources for an example of the importance of growing genetically diverse crops and chances are that sooner or later they’ll mention the Irish potato famine, caused by the late blight fungus Phytophtora infestans in the 1840s. But for such an important – and iconic – disease, it is amazing how what we think we know about it keeps changing. There’s been a re-think recently about which strain of the fungus actually caused the outbreak in Ireland. And now there’s DNA work to figure out where the pathogen came from. The debate on that point seems now to have been decided in favour of the Andes.
White grapes are mutants
Thought that would get your attention. Actually, what the research summarized here revealed was that a couple of genes mutated independently thousands of years ago in the ancestor of the modern grapevine, whose berries were red. The resulting white variety proved to be the ancestor of almost all of the 3000 or so white grape varieties we have today. This discovery from CSIRO will apparently be useful in marker-assisted breeding.
Longhorns registered
A surprisingly detailed – for this kind of thing – article in the News-Journal describes efforts to preserve the breed of cattle known as the Texas Longhorn. This apparently developed from cattle introduced from Spain to what is now Mexico around 1500. It was the mainstay of the Texan cattle industry until railroads replaced the traditional cattle drive (much seen in John Wayne movies) at the end of the 19th century. Their long horns meant you could fit fewer of them into the cattle-trucks. It has since been much altered by cross-breeding, and, predictably, this loss of “purity” has upset some people, while no doubt leaving others to mutter “So what?”, probably under their breath. Anyway, there’s a registry, and a DNA database is underway. Lots more interesting detail in the article.
Want to save diversity? Talk to a local
A report from the annual meeting of the American Association for the Advancement of Science says that “many animals and plants threatened with extinction could be saved if scientists spent more time talking with the native people whose knowledge of local species is dying out as fast as their languages are being lost”. David Harrison, the scientist whose work is reported, says that the recent DNA-based discovery that a butterfly known to taxonomists as Astraptes fulgerator was in fact three different species (or, perhaps, 10 — did the locals know that?) could have been made much sooner if the scientists had talked to the Tzeltal-speaking people of Mexico, because Tzeltal has several descriptions of the butterflies based on the different kinds of caterpillar. The people distinguish the larvae because the caterpillars eat the peoples crops, whereas the butterflies are of no significance.
“It’s crucial for them to know which larva is eating which crop and at what time of year. Their survival literally depends on knowing that, whereas the adult butterfly has no impact on their crops,” Harrison said.
There must be other agriculturally-informed examples, but the opposite is also often true, creating a nightmare for scientists interested in genetic diversity. Farmers may use the same name for completely different populations of a crop. And they may use different names for genetically identical populations. What’s a poor researcher to do?
p.s (There are a bunch of other studies about names and identity; can I find them? Can I heck.)