Comparative Phylogenomic Assessment of Mitochondrial Introgression among Several Species of Chipmunks (Tamias).

Many species are not completely reproductively isolated, resulting in hybridization and genetic introgression. Organellar genomes, such as those derived from mitochondria (mtDNA) and chloroplasts, introgress frequently in natural systems; however, the forces shaping patterns of introgression are not always clear. Here, we investigate extensive mtDNA introgression in western chipmunks, focusing on species in the Tamias quadrivittatus group from the central and southern Rocky Mountains. Specifically, we investigate the role of selection in driving patterns of introgression. We sequenced 51 mtDNA genomes from six species and combine these sequences with other published genomic data to yield annotated mitochondrial reference genomes for nine species of chipmunks. Genomic characterization was performed using a series of molecular evolutionary and phylogenetic analyses to test protein-coding genes for positive selection. We fit a series of maximum likelihood models using a model-averaging approach, assessed deviations from neutral expectations, and performed additional tests to search for codons under the influence of selection. We found no evidence for positive selection among these genomes, suggesting that selection has not been the driving force of introgression in these species. Thus, extensive mtDNA introgression among several species of chipmunks likely reflects genetic drift of introgressed alleles in historically fluctuating populations.

Novel therapeutics in multiple sclerosis management: clinical applications.

Multiple sclerosis (MS) affects an estimated 300,000 individuals in the United States. No cure exists and although there is a lack of consensus on management, strategies to modify disease course are available. These strategies involve initiating disease-modifying therapies that have been found to slow disease progression and prevent disability symptoms, thereby improving function for MS patients. The overall goal of early disease management is to intervene prior to irreversible neuronal destruction in order to delay disability progression and improve quality of life. Maintaining a lower level of disability for a longer period of time postpones and ultimately attempts to prevent reaching a level of immobility and irreversible disability. However, due to the complex nature of disease and its unique, individual patient course, no patient can be treated alike and no patient responds to therapy similarly. Therefore, MS research is continuous in its evolution of therapeutic development, focusing on neuroprotective effects and agents with distinctive mechanisms of action allowing for unique safety and efficacy profiles. Investigations include novel oral agents and monoclonal antibodies. Many of the approved agents also are continually being investigated in order to evaluate comparative data, the most appropriate means of implementing subsequent therapy upon failure, responsiveness to therapeutic agent when switched, and long-term safety and efficacy. This multimedia webcast educational activity will cover the current state of MS science, current therapies in MS, emerging treatments in clinical trials for MS as well as differences between physicians in diagnosis and management of MS and their evolving practices.