We characterized the complete genome sequence of Siphoviridae bacteriophage Erla, an obligatory lytic subcluster EA1 bacteriophage infecting Microbacterium foliorum NRRL B-24224, with a capsid width of 65 nm and a tail length of 112 nm. The 41.5-kb genome, encompassing 62 predicted protein-coding genes, is highly similar (99.52% identity) to that of bacteriophage Calix.

Phages infecting bacteria of the genus Staphylococcus play an important role in their host's ecology and evolution. On one hand, horizontal gene transfer from phage can encourage the rapid adaptation of pathogenic Staphylococcus enabling them to escape host immunity or access novel environments. On the other hand, lytic phages are promising agents for the treatment of bacterial infections, especially those resistant to antibiotics. As part of an ongoing effort to gain novel insights into bacteriophage diversity, we characterized the complete genome of the Staphylococcus bacteriophage Metroid, a cluster C phage with a genome size of 151kb, encompassing 254 predicted protein-coding genes as well as 4 tRNAs. A comparative genomic analysis highlights strong similarities - including a conservation of the lysis cassette - with other Staphylococcus cluster C bacteriophages, several of which were previously characterized for therapeutic applications.

20 Phages infecting bacteria of the genus Staphylococcus play an important role in their host's 21 ecology and evolution. On one hand, horizontal gene transfer from phage can encourage the rapid 22 30 31 key words: bacteriophage; Staphylococcus; Myoviridae; genome assembly 32

Earth’s physiographic features shape the genetic evolution of organisms. Understanding the conditions under which such features act as barriers to gene flow requires quantifying and articulating the features of both the barrier and the organism(s). Many such physiographic features, however, have known interdependencies that are not expressed through common multivariate statistics. Here, we evaluate the use of directed acyclic (causal) graphs and structural equation modeling (SEM) to articulate and test these relationships. We chose the longstanding and contested Riverine Barrier Hypothesis as a test-case using 28 river-spanning population genomic datasets of plants and animals associated with 25 rivers across the contiguous United States; data were paired with seasonality, river width, and river discharge data for those rivers. SEMs revealed insights that could not be captured by traditional non-structured multivariate statistics. Discharge had the greatest direct effect on low-dispersing species. However, discharge has negative, indirect effects on other river features making its total effect on population differentiation negligible. River width was important for low dispersers, but surprisingly, narrower rivers were associated with higher Fst—this may be due to the association of higher topography with narrower (e.g., headland) parts of rivers. Or, wide lowland rivers may be more dynamic and facilitate dispersal more than highland rivers. Therefore, topography or landscape history and not wetted river area may determine barrier efficacy. This proof of concept shows the utility of causal graphs and SEM at articulating and testing complex relationships between Earth’s physiographic features and the organisms that evolve with them.