This image comes from the paper Archaeological Soybean (Glycine max) in East Asia: Does Size Matter?—which also includes a few other interesting photos of fossilized soybeans. The authors explain that their paper “critically reviews archaeological soybean size and its usefulness to understanding the relationship between people and soybean in East Asia.”
In addition to being interesting in and of itself, I think this paper demonstrates PLoS ONE’s breadth of scope. As the authors mention, tracking the domestication of what has come to be one of the world’s most important crops is an interdisciplinary endeavor, requiring input from physical and cultural anthropologists, evolutionary biologists, and taxonimists, among others. At PLoS ONE, they can all publish under one roof.
From the Abstract:
The recently acquired archaeological record for soybean from Japan, China and Korea is shedding light on the context in which this important economic plant became associated with people and was domesticated. This paper examines archaeological (charred) soybean seed size variation to determine what insight can be gained from a comprehensive comparison of 949 specimens from 22 sites. Seed length alone appears to represent seed size change through time, although the length×width×thickness product has the potential to provide better size change resolution. A widespread early association of small seeded soybean is as old as 9000–8600 cal BP in northern China and 7000 cal BP in Japan. Direct AMS radiocarbon dates on charred soybean seeds indicate selection resulted in large seed sizes in Japan by 5000 cal BP (Middle Jomon) and in Korea by 3000 cal BP (Early Mumun). Soybean seeds recovered in China from the Shang through Han periods are similar in length to the large Korean and Japanese specimens, but the overall size of the large Middle and Late Jomon, Early Mumun through Three Kingdom seeds is significantly larger than any of the Chinese specimens. The archaeological record appears to disconfirm the hypothesis of a single domestication of soybean and supports the view informed by recent phyologenetic research that soybean was domesticated in several locations in East Asia.
Citation: Lee G-A, Crawford GW, Liu L, Sasaki Y, Chen X (2011) Archaeological Soybean (Glycine max) in East Asia: Does Size Matter? PLoS ONE 6(11): e26720. doi:10.1371/journal.pone.0026720