Mutation in the tropical tree canopy

Genetic diversity is an essential prerequisite for the capacity of all life to adapt to an ever-changing environment, and trees are notorious for their large standing genetic variation. There are several ways by which genetic variation can be incorporated or reshuffled in a species, but the only way of generating truly novel genetic diversity is through mutation. Scientists have dedicated considerable efforts to understand the roles of phylogeography, local adaptation, speciation, and hybridisation in modulating genetic diversity of tropical trees, however, our current knowledge of mutational processes in tropical trees is very limited. Recent advances in DNA sequencing techniques now allow us to detect single point mutations with unprecedented precision, which opens up exciting possibilities in mutation research. We propose to sequence the genomes of tropical rainforest trees in French Guiana, providing, for the first time, reference genomes of three Neotropical rainforest tree species. We will test intra-individual and inter-specific effects of low to extreme canopy sunlight exposure on the accumulation of novel mutations. The tree architecture (i.e., the branching pattern) will represent the null hypothesis for the pattern of accumulation of mutations. We will test the existence of a soma vs. germline segregation in tropical trees and the transmission of novel mutations from parent to offspring. The genomic data and knowledge to be generated in the project represent crucial information towards understanding genome evolution and its drivers in long-lived organisms. The comparison of mutational processes among tropical species, combined with the potential retention of mutations in offspring should be invaluable in assessing the importance of mutation rates in the creation and maintenance of Neotropical diversity.