The genetic diversity of the starchy crop known as manioc—which produces the edible root cassava, a staple of African diets—depends on more on human culture than one might have guessed. Specifically, the crop’s fate appears to be tied to the marriages of people within the small farming communities of Gabon, Africa, according to new research published today (October 31) in Proceedings of the National Academy of Sciences.
To decipher this bizarre relationship, Marc Delêtre of Trinity College Dublin and his colleagues collected manioc from 10 villages, genotyped the crops, and found that certain regions carried more genetic diversity than others. Specifically, the researchers found high levels of diversity in the southern part of the country, where women move to their husbands’ villages after marriage, bringing with her manioc varieties from her home farm. In the north, on the other hand, new brides receive manioc crops from their new mothers-in-law, but do not bring any from home. Correspondingly, manioc crops of the northern region had a much lower level of diversity.
“Little attention has been paid to the central role of strategies of social reproduction in shaping crop genetic diversity at local and regional levels,” the authors wrote. “However, by connecting or disconnecting human populations, kinship systems can influence the genetic structure of crop populations just as they influence genetic diversity in human populations.”