The comparative genomic landscape of adaptive radiation in crater lake cichlid fishes.

Factors ranging from ecological opportunity to genome composition might explain why only some lineages form adaptive radiations. While being rare, particular systems can provide natural experiments within an identical ecological setting where species numbers and phenotypic divergence in two closely related lineages are notably different. We investigated one such natural experiment using two de novo assembled and 40 resequenced genomes and asked why two closely related Neotropical cichlid fish lineages, the Amphilophus citrinellus species complex (Midas cichlids; radiating) and Archocentrus centrarchus (Flyer cichlid; nonradiating), have resulted in such disparate evolutionary outcomes. Although both lineages inhabit many of the same Nicaraguan lakes, whole-genome inferred demography suggests that priority effects are not likely to be the cause of the dissimilarities. Also, genome-wide levels of selection, transposable element dynamics, gene family expansion, major chromosomal rearrangements and the number of genes under positive selection were not markedly different between the two lineages. To more finely investigate particular subsets of the genome that have undergone adaptive divergence in Midas cichlids, we also examined if there was evidence for 'molecular pre-adaptation' in regions identified by QTL mapping of repeatedly diverging adaptive traits. Although most of our analyses failed to pinpoint substantial genomic differences, we did identify functional categories containing many genes under positive selection that provide candidates for future studies on the propensity of Midas cichlids to radiate. Our results point to a disproportionate role of local, rather than genome-wide factors underlying the propensity for these cichlid fishes to adaptively radiate.

Clinical Management of Children with Oropharyngeal Aspiration - Physician Survey.

Introduction: Pulmonary aspiration in infants and children is common, with 25% of the pediatric population reported to experience some type of nonspecific swallowing dysfunction. Diagnosing and managing oropharyngeal aspiration remain a challenging task due to the lack of distinguishing clinical or laboratory characteristics. We conducted a large, physician-based survey in an effort to determine the differences in the diagnosis and management of patients with oropharyngeal aspiration across different centers, using a quantitative online questionnaire. Methods: A survey was developed with the goal of understanding the physician demographics, diagnosis, management strategies, and the role of specialized centers for airway, voice, and swallowing disorders (also known as Aerodigestive Disease Centers). The questionnaire was sent to the pediatric membership of the American Thoracic Society. Results: A total of 136 questionnaires were completed and physicians from 42 different Aerodigestive Digestive Centers participated in the survey. Ninety-two percent of respondents believed that the evidence is unclear on the best methods for diagnosing lung disease related to oropharyngeal aspiration. Modified barium swallow (MBS) study and fiberoptic endoscopic evaluation of swallowing were the most useful studies in making the diagnosis of the oropharyngeal aspiration according to the participants. The majority of the participants preferred to repeat the feeding evaluations and MBS after the initial intervention. For children with suspected or confirmed aspiration, 68.6% of the respondents stated that they combine endoscopy and flexible and/or rigid bronchoscopy for further evaluation, while 27.1% preferred to perform the procedures individually at the discretion of each specialty provider. Inhaled corticosteroids were mostly prescribed if there was any component of bronchial hyperreactivity, and acid suppression therapy was primarily prescribed if there was a diagnosis or suspicion of gastroesophageal reflux disease. Empirical thickening of the feeds was not uniformly performed among the aerodigestive centers as a therapy method for the children with swallowing dysfunction with aspiration. Conclusion: In the survey, physicians mentioned about the importance of better guidelines for aspiration, the requirement of new diagnostic measures, the necessity of multicenter trials of sensitivity and specificity of current diagnostic tools, and developing a scoring system for reading the radiological studies for children with oropharyngeal aspiration.