RESUMO
The opposing forces of gene flow and isolation are two major processes shaping genetic diversity. Understanding how these vary across space and time is necessary to identify the environmental features that promote diversification. The detection of considerable geographic structure in taxa from the arid Nearctic has prompted research into the drivers of isolation in the region. Several geographic features have been proposed as barriers to gene flow, including the Colorado River, Western Continental Divide, and a hypothetical Mid-Peninsular Seaway in Baja California. However, recent studies suggest that the role of barriers in genetic differentiation may have been overestimated when compared to other mechanisms of divergence. In this study, we infer historical and spatial patterns of connectivity and isolation in Desert Spiny Lizards (Sceloporus magister) and Baja Spiny Lizards (S. zosteromus), which together form a species complex composed of parapatric lineages with wide distributions in arid western North America. Our analyses incorporate mitochondrial sequences, genomic-scale data, and past and present climatic data to evaluate the nature and strength of barriers to gene flow in the region. Our approach relies on estimates of migration under the multispecies coalescent to understand the history of lineage divergence in the face of gene flow. Results show that the S. magister complex is geographically structured, but we also detect instances of gene flow. The Continental Divide is a strong barrier to gene flow, while the Colorado River is more permeable. Analyses yield conflicting results for the catalyst of differentiation of peninsular lineages in S. zosteromus. Our study shows how large-scale genomic data for thoroughly sampled species can shed new light on biogeography. Furthermore, our approach highlights the need for the combined analysis of multiple sources of evidence to adequately characterize the drivers of divergence.
RESUMO
Objective@#To investigate the feasibility of using a carbon dioxide(CO2) laser in the treatment of facial papilloma in children and to evaluate its curative effect and prognosis.@*Methods @#A case of pediatric facial papilloma treated with a CO2 laser was reported, and the effects of this disease and CO2 laser treatment were reviewed and analyzed in combination with the literature. @* Results@#Under general anesthesia, the lesion tissue of the left lip was excised for pathological biopsy, and the diagnosis was maxillofacial papilloma. The lesions were surgically ablated in stages with a CO2 laser, and erythromycin ointment was applied to the surgical incision after surgery. A total of three rounds of CO2 laser treatment were performed for 3 treatment courses. The child had no complications during or after the operation, the facial appearance was significantly improved, and there was no sign of recurrence during the 6-month follow-up. A literature review showed that CO2 lasers have been widely used in the excision of various surface lesions. In clinical practice, continuous CO2 laser with power of 10-50 W and wavelength of 10.6 μm is used to treat superficial tissue lesions, which can achieve accurate vaporization resection of diseased tissue, less bleeding and a good prognosis.@* Conclusion@#CO2 laser was accurate and minimally invasive for the removal of facial papilloma in children.
