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.)
More money for tomato genomes
Here’s one that squeaked under the radar a while back. The US is investing US$1.8 million to continue sequencing the tomato and other related plants of the Solanacae family. According to a press release, the work will form part of the “comprehensive International Solanaceae Genomics Project (SOL) Genomics Network database. This will tie together maps and genomes of all plants in the Solanaceae family, also called nightshades, which includes the potato, eggplant, pepper and petunia and is closely related to coffee from the Rubiaceae family.” The data will be fully public.
Just to bring the tomato back down to earth, genius writer Harold McGee points to a scientific paper that could help growers produce tastier tomatoes with absolutely no genomic knowledge. Water them with a dilute salt solution. A solution of 0.1% sodium chloride results in tomatoes with “significantly higher levels of flavorful organic acids and sugars, and as much as a third more vitamin C and beta-carotene (the precursor to vitamin A) and the antioxidant red pigment lycopene,” McGee says. The tomatoes are smaller, but who cares?