Genetic and Epigenetic Views of the Adaptive Evolution of Oaks (Quercus L.)

The long-lived angiosperm Quercus L. (Oaks) have emerged as promising model organisms for investigating adaptive divergence and ecological environmental interactions due to their longevity and large genetic diversity as well as recurrent gene flow among species with diverse natural habitats. Until recently, numerous genomic studies by new high-throughput sequencing platforms have provided access to link genes with ecological and physiological traits. However, the genetic and epigenetic mechanisms underlying the adaptive evolution of oak trees are still poorly understood. In this review, we summarise the current progress of reported oak genomes and inheritance systems, analysing the epigenetics and genetic structure of oaks. We review evidence regarding the genetic mechanism linking introgressive hybridisation and reproductive isolation for a better understanding of adaptive divergence and defining speciation in oaks. Furthermore, we also discuss the interaction and evolution between oaks, other organisms and the environment to explore the adaptive strategies and coevolutionary mechanisms among them. Through the impact of this article, hopefully, a distinctive avenue could be established to further study the inheritance, ecology and multidimensional evolution of oaks.