The standard story of Pacific colonization is that people and their crops and livestock spread across it in a generally southwestern direction. Scientists from Durham University and the University of Oxford are renavigating the details. They looked at DNA from various pigs across the Pacific, and conclude that their journey may have started in what is now Vietnam. It has always been assumed that the people and their agriculture traveled together as a single package. This research indicates that different parts of the package took different routes.
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.
It is easy to forget sometimes that The Origin of Species actually starts with a lengthy discussion of genetic diversity in crops, ornamentals, livestock and pets, although of course Darwin doesn’t call it that. He calls it “variation under domestication,” and you can now hear his seminal words, by downloading 24 hours’ worth of audio files from here. There’s a also a link to an e-text of the book.
I blogged some time ago about a new project at the University of Manchester to document Pharaoh’s herbal medicines, but there was not much detail in the press release I quoted at the time. Now there’s a much fuller article on Discovery. It seems that the ancient Egyptians were martyrs to constipation.
There’s quite a debate going on about what the Americas – and in particular the Amazon – looked like before Columbus arrived. This has been the subject of a bestseller entitled 1491, whose main arguments are summarized by the author, Charles Mann, here. It is always dangerous to simplify academic controversies as being between two diametrically opposing camps, but I’ll do it anyway. One side thinks that population levels were high in the Americas in pre-Columbian times, and that even the Amazon was essentially a gigantic, closely managed orchard, hence talk of the “pristine myth.” The other side thinks that the real myth is that of a large, widespread human population in the Amazon. This has important practical implications because, inevitably, some have seized on the debate to argue that the Amazon could be more heavily exploited today, because it was in the past.
Coincidentally, there are stories today which summarize papers coming down on opposing sides of this argument.
According to this piece, Dolores R. Piperno of the Smithsonian Tropical Research Institute in Panama and National Museum of Natural History in Washington, DC, “found evidence of widespread fire use for land-clearing by pre-Colombian populations in Latin America” when she reconstructed vegetation patterns and fire histories from pollen, phytolyth and charcoal records.
Noting the vast body of research indicates the existence of large, dense, sedentary populations in the Amazon, Piperno implies that conservationists should come to terms with the fact that tropical forests have been cleared in the past as they are being cleared today, and then move forward with effective strategies for preserving what remains.
A different view emerges in this discussion of the work of Mark Bush of the Florida Institute of Technology in Melbourne. He looked at charcoal and pollen records at two Amazonian lakes and found that
…rather than being widely dispersed, people living in the Amazon most likely clustered near the good places, and that overall population numbers were likely not as high as the top estimates of pre-Columbian people.
This will run and run.