Asymmetric genetic differentiation: evidence for hybridization between
two sympatric termite species in nature
AbstractHybridization between species is likely to be associated with a new
ecological impact. However, in termites, reports of hybridization mostly
focus on hybrid zones caused by species invasion or the development of
initial-stage colonies. In this study, we combined microsatellite
genotyping with mitochondrial DNA sequencing to investigate the
hybridization and adaptive introgression between two sympatric,
long-differentiated related termite species, Reticulitermes flaviceps
and R. chinensis, in nature. Similar levels of mitochondrial and nuclear
genetic diversity were found in R. flaviceps and R. chinensis.
Asymmetric interspecific genetic differentiation was observed between
mitochondrial and nuclear genes, with high genetic divergence found in
mitochondrial DNA but low genetic divergence in nuclear genes. Our
results indicated a lack of mitochondrial gene exchange in R. flaviceps
and R. chinensis but unconstrained nuclear introgression between them.
This asymmetric genetic differentiation between nuclear and cytoplasmic
material strongly suggests that there is interspecific hybridization
between R. flaviceps and R. chinensis in nature, which provides new
insight into the dynamics of hybridization and its potential
consequences for speciation in termites.