Tonya Lander (Life Sciences, The Natural History Museum) has just completed her analyses of the population structure of the Maya Nut tree (Brosimum alicastrum). The results are based on the use of genetic markers and are really interesting. They tell us something about not only the history of this species but how best the species can be managed. This is important because Maya Nut is a significant famine food for the rural poor in northern Central America and is being actively used in reforestation projects as it is fast growing and relatively tolerant of disturbance. The work has been funded by Defra through the Darwin Initiative (project 18-010).
Brosimum alicastrum forest in Mexico
Female flower of Brosimum alicastrum
The tree is relatively common throught Central America and South America north of the Amazon. The markers that we have used are from the chlroroplast and nuclear ribosome genomes of the plant and were collected from 34 populations across Central and South America. Many of the samples were collected by the women who harvest the Maya Nut. which provided us with the opportunity to connect rural communities with scientists the other side of the World.
Tonya's results provide evidence for distinct northern and southern genetic types (Figure 1), and possibly for Atlantic and Pacific genetic types (Figure 2). These results still need to be tested for statistical significance but will help to clarify whether B. alicastrum fits into the broadly recognized historical pattern of retreat into the Amazon basin during the last glacial maximum followed by post-glacial expansion north into Central America. Each grouping represents a potential land race or ecotype and if confirmed will represent the framework within which seeds can deployed for reforestation.
Figure 1. Five distinct sub-groups of Brosimum alicastrum: (1) Peru (dark pink), (2)Panama (bright pink), (3) ‘Southern’: Brazil, Columbia, Panama, Nicaragua, Honduras, El Salvador, Belize, Cuba, Mexico (light blue), (4) Costa Rica (dark blue), and (5) ‘Northern’: El Salvador, Guatemala, Belize, Mexico (pale pink)