Do natural hybridization and asymmetric introgression at the distribution margin of two Buddleja species with a large overlap?
The occurrence of morphologically intermediate individuals between B. crispa and B. officinalis at Xishan Mountain is unequivocally linked to hybridization and almost all examined individuals of the putative hybrids were likely F1s. Despite pollination experiments indicating higher chances for introgression into B. officinalis (hybrids only produced viable seed when crossed with B. officinalis), observed introgression was asymmetrical into B. crispa. This could be due to seeds produced by hybrids not contributing to seedlings, or other factors favoring the establishment of backcrosses towards B. crispa. However, further research will be needed to confirm these observations, as the small number of plants used for the pollination experiments could have introduced an artifact, for example if used individuals were more or less compatible than the species average, and also the small number of loci used could convey a picture of introgression that is not representative for the whole genome.
This study provides a practical tool that uses significant prognostic factors to predict which patients with preoperatively diagnosed N2 non-small cell lung cancer have better prognoses. Because patients with the favorable prognostic factors showed good long-term survival and excellent local disease control, surgery should still play an important role in the multimodality treatment of these patients.