You discuss the implications of the unpublished discovery of DNA from maize (corn) in ancient faeces from two pre-Columbian cultures on Vieques Island, Puerto Rico (Nature http://doi.org/s8g; 2014). We question the inference from this discovery that one culture, the Huecoid people, originated from the Bolivian Andes.

That inference is presumably based on the assumption that maize and chicha (a fermented maize beverage) were produced in Bolivia. However, both items were widely used throughout pre-Columbian America during Huecoid times in 400 BC to AD 600 (see, for example, R. M. Bonzani and A. Oyuela-Caycedo in Histories of Maize 343–356; Academic Press, 2006). Maize was also already present among pre-Arawak Antillean groups by 2950 BC and, contrary to your speculations, was not introduced into Puerto Rico by the Huecoid people (see J. R. Pagán-Jiménez in The Oxford Handbook of Caribbean Archaeology 391–406; Oxford Univ. Press, 2013).

The archaeological evidence of early Caribbean societies therefore indicates that Puerto Rican natives may have had earlier and more wide-ranging origins than your report implies (see also R. Rodríguez-Ramos Rethinking Puerto Rican Precolonial History; Univ. Alabama Press, 2010).