Factors contributing to mitogenome size variation and a recurrent intracellular DNA transfer in Melastoma.

Background: Mitogenome sizes of seed plants vary substantially even among closely related species, which are often related to horizontal or intracellular DNA transfer (HDT or IDT) events. However, the mechanisms of this size variation have not been well characterized.

Results: Here we assembled and characterized the mitogenomes of three species of Melastoma, a tropical shrub genus experiencing rapid speciation.

Balancing selection on an MYB transcription factor maintains the twig trichome color variation in Melastoma normale.

Background: The factors that maintain phenotypic and genetic variation within a population have received long-term attention in evolutionary biology. Here the genetic basis and evolution of the geographically widespread variation in twig trichome color (from red to white) in a shrub Melastoma normale was investigated using Pool-seq and evolutionary analyses.

Results: The results show that the twig trichome coloration is under selection in different light environments and that a 6-kb region containing an R2R3 MYB transcription factor gene is the major region of divergence between the extreme red and white morphs.