Biology subjects

Sanchez, D. E.

Publications and source records attributed to Sanchez, D. E..

4 recordsLinked to original sources

bioRxiv2026

Is a dam-altered river in the U.S. Southwest a barrier to dispersal for populations of a common lizard, Uta stansburiana?

Dams can significantly alter natural riverine systems, but their impact on movement across rivers for most terrestrial vertebrates is poorly known. The completion of Glen Canyon and Flaming Gorge dams in Arizona and Utah (southwestern United States) profoundly changed the Colorado and Green Rivers and have altered habitat for many species. The common side-blotched lizard (Uta stansburiana) offers an excellent opportunity to examine the effects of riverine impoundments on migration and gene flow in terrestrial biodiversity. To assess these effects, we collected tissue samples from 241 Uta stansburiana above and below Glen Canyon Dam and on both sides of the Colorado river at three separate study areas. We used eight microsatellite loci to estimate genetic exchange in the context of genetic diversity and structure. One study area below Flaming Gorge Dam and above Glen Canyon Dam has annual periods of warmer water temperatures and lower flows that are closer to pre-dam conditions, whereas two study areas below Glen Canyon Dam have cold water temperatures year-round, and less pronounced seasonal low flow episodes. We predicted that warmer water temperatures above Glen Canyon Dam would promote greater genetic exchange among populations than below the dam. However, we found evidence for low levels of genetic exchange between sites both above and below Glen Canyon Dam, and a moderate amount of exchange at a site below this dam where lizards could conceivably move from one side to the other. Our results imply that 1) the changes in water temperature and hydrology in dam-altered rivers are a barrier for this species even when the distance from the dam is great; and 2) genetic exchange may be dependent on river morphology. These results are relevant to other small vertebrates, particularly ectotherms, that occupy habitat proximal to a dammed river and has implications for the conservation management of impounded river systems.

zoology↗

bioRxiv2023

Single B cell transcriptomics identifies multiple isotypes of broadly neutralizing antibodies against flaviviruses

Sequential dengue virus (DENV) infections often generate neutralizing antibodies against all four DENV serotypes and sometimes, Zika virus. Characterizing cross-flavivirus broadly neutralizing antibody (bnAb) responses can inform countermeasure strategies that avoid infection enhancement associated with non-neutralizing antibodies. Here, we used single cell transcriptomics to mine the bnAb repertoire following secondary DENV infection. We identified several new bnAbs with comparable or superior breadth and potency to known bnAbs, and with distinct recognition determinants. Unlike all known flavivirus bnAbs, which are IgG1, one newly identified cross-flavivirus bnAb (F25.S02) was derived from IgA1. Both IgG1 and IgA1 versions of F25.S02 and known bnAbs displayed neutralizing activity, but only IgG1 enhanced infection in monocytes expressing IgG and IgA Fc receptors. Moreover, IgG-mediated enhancement of infection was inhibited by IgA1 versions of bnAbs. We demonstrate a role for IgA in flavivirus infection and immunity with implications for vaccine and therapeutic strategies.

microbiology↗

bioRxiv2022

Once upon a time in Mexico: Holocene phylogeography of the spotted bat (Euderma maculatum)

Holocene-era range expansions are relevant to understanding how a species might respond to the warming and drying climates of today. The harsh conditions of North American deserts have phylogenetically structured desert bat communities but differences in flight capabilities are expected to affect their ability to compete, locate, and use habitat in the face of modern climate change. A highly vagile but data-deficient bat species, the spotted bat (Euderma maculatum) is thought to have expanded its range from central Mexico to western Canada during the Holocene. With specimens spanning this latitudinal extent, we coupled phylogeography (mtDNA) with ecological niche modeling (ENM) to investigate the Holocene biogeography from the rear to leading edges. The ENM and phylogeny supported a Holocene range expansion from Mexico with increased expansion throughout the intermountain west within the last 6 kya. Long-term isolation at the southern-most margin of the range suggests one or more populations were left behind as climate space contracted and are currently of unknown status. The species appears historically suited to track shifts in climate space but differences in flight behaviors between leading edge and core-range lineages suggest that range expansions could be influenced by differences in habitat quality or climate (e.g., drought). Although its vagility could facilitate the tracking of environmental change and thereby extinction avoidance, anthropogenic pressures at the core range could still threaten the ability for beneficial alleles to expand into the leading edge.

genetics↗

bioRxiv2022

Detecting bat environmental DNA from water-filled road-ruts in upland forest

Declines in population and diversity of North American bats are rapidly occurring due to habitat loss, incidental take from various industry projects, and lethal White-nose Syndrome disease. It is critical to accurately census habitat for appropriate conservation measures, yet traditional sampling methodology, such as mist netting and acoustic recordings, can be time-intensive and biased. Instead, a passive sampling tool that does not rely on the a priori knowledge of bat roosts may provide crucial information on bat communities. In the water-limited habitats of forested uplands of the Appalachian Plateau, water-filled road-ruts are important resources for bats. Therefore, we developed an environmental DNA (eDNA) protocol to sample isolated road-ruts that may have the presence of sloughed cellular material from actively drinking bats. The detection of bat eDNA was investigated from a positive control experiment, and across 47 water samples collected in Kentucky and Ohio. Water samples were analyzed using both species-specific quantitative polymerase chain reaction (qPCR) and community metabarcoding methodologies. Using qPCR analysis, we detected eDNA from big brown bat (Eptesicus fuscus) and eastern red bat (Lasiurus borealis) from water-filled road-ruts. While the community metabarcoding approach failed to detect any bat eDNA, many non-target amphibians, birds, and mammals were identified. These results suggest eDNA found within road-ruts provides an additional detection tool for surveying biodiversity across upland forests. Additionally, the use of qPCR increased the detection of rare eDNA targets, which will be crucial for properly implementing future eDNA applications for improving bat conservation efforts across the landscape. Article impact statementEnvironmental DNA provides detection of bats from drinking sources offering a novel survey method for management and conservation efforts

ecology↗