Genetic variants associated with hantavirus infection in a reservoir host are related to regulation of inflammation and immune surveillance.

The immunogenetics of wildlife populations influence the epidemiology and evolutionary dynamic of the host-pathogen system. Profiling immune gene diversity present in wildlife may be especially important for those species that, while not at risk of disease or extinction themselves, are host to diseases that are a threat to humans, other wildlife, or livestock. Hantaviruses (genus: Orthohantavirus) are globally distributed zoonotic RNA viruses with pathogenic strains carried by a diverse group of rodent hosts. The marsh rice rat (Oryzomys palustris) is the reservoir host of Orthohantavirus bayoui, a hantavirus that causes fatal cases of hantavirus cardiopulmonary syndrome in humans. We performed a genome wide association study (GWAS) using the rice rat "immunome" (i.e., all exons related to the immune response) to identify genetic variants associated with infection status in wild-caught rice rats naturally infected with their endemic strain of hantavirus. First, we created an annotated reference genome using 10× Chromium Linked Reads sequencing technology. This reference genome was used to create custom baits which were then used to target enrich prepared rice rat libraries (n = 128) and isolate their immunomes prior to sequencing. Top SNPs in the association test were present in four genes (Socs5, Eprs, Mrc1, and Il1f8) which have not been previously implicated in hantavirus infections. However, these genes correspond with other loci or pathways with established importance in hantavirus susceptibility or infection tolerance in reservoir hosts: the JAK/STAT, MHC, and NFκB. These results serve as informative markers for future exploration and highlight the importance of immune pathways that repeatedly emerge across hantavirus systems. Our work aids in creating cross-species comparisons for better understanding mechanisms of genetic susceptibility and host-pathogen coevolution in hantavirus systems.

Library preparation method and DNA source influence endogenous DNA recovery from 100-year-old avian museum specimens.

Museum specimens collected prior to cryogenic tissue storage are increasingly being used as genetic resources, and though high-throughput sequencing is becoming more cost-efficient, whole genome sequencing (WGS) of historical DNA (hDNA) remains inefficient and costly due to its short fragment sizes and high loads of exogenous DNA, among other factors. It is also unclear how sequencing efficiency is influenced by DNA sources. We aimed to identify the most efficient method and DNA source for collecting WGS data from avian museum specimens. We analyzed low-coverage WGS from 60 DNA libraries prepared from four American Robin (Turdus migratorius) and four Abyssinian Thrush (Turdus abyssinicus) specimens collected in the 1920s. We compared DNA source (toepad versus incision-line skin clip) and three library preparation methods: (1) double-stranded DNA (dsDNA), single tube (KAPA); (2) single-stranded DNA (ssDNA), multi-tube (IDT); and (3) ssDNA, single tube (Claret Bioscience). We found that the ssDNA, multi-tube method resulted in significantly greater endogenous DNA content, average read length, and sequencing efficiency than the other tested methods. We also tested whether a predigestion step reduced exogenous DNA in libraries from one specimen per species and found promising results that warrant further study. The ~10% increase in average sequencing efficiency of the best-performing method over a commonly implemented dsDNA library preparation method has the potential to significantly increase WGS coverage of hDNA from bird specimens. Future work should evaluate the threshold for specimen age at which these results hold and how the combination of library preparation method and DNA source influence WGS in other taxa.

Investigating the utility of traditional and genomic multi-locus datasets to resolve relationships in Lipaugus and Tijuca (Cotingidae).

Rapid diversification limits our ability to resolve evolutionary relationships and examine diversification history, as in the case of the Neotropical cotingas. Here we present an analysis with complete taxon sampling for the cotinga genera Lipaugus and Tijuca, which include some of the most range-restricted (e.g., T. condita) and also the most widespread and familiar (e.g., L. vociferans) forest birds in the Neotropics. We used two datasets: (1) Sanger sequencing data sampled from eight loci in 34 individuals across all described taxa and (2) sequence capture data linked to 1,079 ultraconserved elements and conserved exons sampled from one or two individuals per species. Phylogenies estimated from the Sanger sequencing data failed to resolve three nodes, but the sequence capture data produced a well-supported tree. Lipaugus and Tijuca formed a single, highly supported clade, but Tijuca species were not sister and were embedded within Lipaugus. A dated phylogeny confirmed Lipaugus and Tijuca diversified rapidly in the Miocene. Our study provides a detailed evolutionary hypothesis for Lipaugus and Tijuca and demonstrates that increasing genomic sampling can prove instrumental in resolving the evolutionary history of recent radiations.