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Assessment Of Intra And Interregional Genetic Variation In The Eastern Red-Backed Salamander, Plethodon Cinereus, Via Analysis Of Novel Microsatellite Markers, Alexander C. Cameron

Biology

The red-backed salamander (Plethodon cinereus) has long-served as a model system in ecology, evolution, and behavior, and studies surveying molecular variation in this species have become increasingly common over the past decade. However, difficulties are commonly encountered when extending microsatellite markers to populations that are unstudied from a genetic perspective due to high levels of genetic differentiation across this species’ range. To ameliorate this issue, we used 454 pyrosequencing to identify hundreds of microsatellite loci. We then screened 40 of our top candidate loci in populations in Virginia, Pennsylvania, and Ohio—including an isolated island population ~ 4.5 km off the …

There’S More Than One Way To Climb A Tree: Limb Length And Microhabitat Use In Lizards With Toe Pads, Travis J. Hagey, Scott Hart, Matthew Vickers, Luke J. Harmon, Lin Schwarzkopf

Biology

Ecomorphology links microhabitat and morphology. By comparing ecomorphological associations across clades, we can investigate the extent to which evolution can produce similar solutions in response to similar challenges. While Anolis lizards represent a well-studied example of repeated convergent evolution, very few studies have investigated the ecomorphology of geckos. Similar to anoles, gekkonid lizards have independently evolved adhesive toe pads and many species are scansorial. We quantified gecko and anole limb length and microhabitat use, finding that geckos tend to have shorter limbs than anoles. Combining these measurements with microhabitat observations of geckos in Queensland, Australia, we observed geckos using similar …

Conflicting Evolutionary Histories Of The Mitochondrial And Nuclear Genomes In New World Myotis Bats, Thomas Lee Jr.

Biology

The rapid diversification of Myotis bats into more than 100 species is one of the most extensive mammalian radiations available for study. Efforts to understand relationships within Myotis have primarily utilized mitochondrial markers and trees inferred fromnuclear markers lackedresolution. Our current understanding of relationships withinMyotis is therefore biased towards a set of phylogenetic markers that may not reflect the history of the nuclear genome. To resolve this,we sequenced the full mitochondrial genomes of 37 representativeMyotis, primarily fromtheNewWorld, in conjunction with targeted sequencing of 3648 ultraconserved elements (UCEs). We inferred the phylogeny and explored the effects of concatenation and summary phylogenetic …

Tempo And Mode Of Performance Evolution Across Multiple Independent Origins Of Adhesive Toe Pads In Lizards, Travis J. Hagey, Josef C. Uyeda, Kristen E. Crandell, Jorn A. Cheney, Kellar Autumn, Luke J. Harmon

Biology

Understanding macroevolutionary dynamics of trait evolution is an important endeavor in evolutionary biology. Ecological opportunity can liberate a trait as it diversifies through trait space, while genetic and selective constraints can limit diversification. While many studies have examined the dynamics of morphological traits, diverse morphological traits may yield the same or similar performance and as performance is often more proximately the target of selection, examining only morphology may give an incomplete understanding of evolutionary dynamics. Here, we ask whether convergent evolution of pad-bearing lizards has followed similar evolutionary dynamics, or whether independent origins are accompanied by unique constraints and selective …

Genomic Analysis Of Factors Associated With Low Prevalence Of Antibiotic Resistance In Extraintestinal Pathogenic Escherichia Coli Sequence Type 95 Strains, Craig M. Stephens, Sheila Adams-Sapper, Manraj Sekhon, James R. Johnson, Lee W. Riley

Biology

Extraintestinal pathogenic Escherichia coli (ExPEC) strains belonging to multilocus sequence type 95 (ST95) are globally distributed and a common cause of infections in humans and domestic fowl. ST95 isolates generally show a lower prevalence of acquired antimicrobial resistance than other pandemic ExPEC lineages. We took a genomic approach to identify factors that may underlie reduced resistance. We fully assembled genomes for four ST95 isolates representing the four major fimH-based lineages within ST95 and also analyzed draft-level genomes from another 82 ST95 isolates, largely from the western United States. The fully assembled genomes of antibiotic-resistant isolates carried resistance genes exclusively on …

Competition From Bromus Tectorum Removes Differences Between Perennial Grasses In N Capture And Conservation Strategies, Rebecca E. Drenovsky, Jeffrey T. Walker, J. J. James

Biology

Background and aims

Competition from the annual grass Bromus tectorum threatens aridland perennial bunchgrass communities. Unlike annuals, perennials must allocate part of their first year nitrogen (N) budget to storage rather than growth, potentially placing them at a competitive disadvantage.

Methods

We evaluated N acquisition and conservation for two perennial bunchgrasses, Agropyron desertorum and Pseudoroegneria spicata, at the seedling stage to investigate potential trade-offs between storage and growth when grown with and without B. tectorum under two levels of soil N.

Results

Agropyron desertorum had higher growth rates, N uptake, and N productivity than P. spicata when grown without …

Genetic Basis For Sex Differences In Obesity And Lipid Metabolism, Jenny Link, Karen Reue

Biology

Men and women exhibit significant differences in obesity, cardiovascular disease, and diabetes. To provide better diagnosis and treatment for both sexes, it is important to identify factors that underlie the observed sex differences. Traditionally, sex differences have been attributed to the differential effects of male and female gonadal secretions (commonly referred to as sex hormones), which substantially influence many aspects of metabolism and related diseases. Less appreciated as a contributor to sex differences are the fundamental genetic differences between males and females, which are ultimately determined by the presence of an XX or XY sex chromosome complement. Here, we review …

Archelosaurian Color Vision, Parietal Eye Loss, And The Crocodylian Nocturnal Bottleneck, Christopher A. Emerling

Biology

Vertebrate color vision has evolved partly through the modification of five ancestral visual opsin proteins via gene duplication, loss, and shifts in spectral sensitivity. While many vertebrates, particularly mammals, birds, and fishes, have had their visual opsin repertoires studied in great detail, testudines (turtles) and crocodylians have largely been neglected. Here I examine the genomic basis for color vision in four species of turtles and four species of crocodylians, and demonstrate that while turtles appear to vary in their number of visual opsins, crocodylians experienced a reduction in their color discrimination capacity after their divergence from Aves. Based on the …

Northern Spotted Owl (Strix Occidentalis Caurina) Genome: Divergence With The Barred Owl (Strix Varia) And Characterization Of Light-Associated Genes, Christopher A. Emerling, Zachary R. Hanna, James B. Henderson, Jeffrey D. Wall, Jérôme Fuchs, Charles Runckel, David P. Mindell, Rauri C. K. Bowie, Joseph L. Derisi, John P. Dumbacher

Biology

We report here the assembly of a northern spotted owl (Strix occidentalis caurina) genome. We generated Illumina paired-end sequence data at 90× coverage using nine libraries with insert lengths ranging from ∼250 to 9,600 nt and read lengths from 100 to 375 nt. The genome assembly is comprised of 8,108 scaffolds totaling 1.26 × 109 nt in length with an N50 length of 3.98 × 106 nt. We calculated the genome-wide fixation index (F_ST) of S. o. caurina with the closely related barred owl (Strix varia) as 0.819. We examined 19 genes that …

Diet, Gonadal Sex, And Sex Chromosome Complement Influence White Adipose Tissue Mirna Expression, Jenny C. Link, Yehudit Hasin-Brumshtei, Rita M. Cantor, Xuqi Chen, Arthur P. Arnold, Aldons J. Lusis, Karen Reue

Biology

Background: MicroRNAs (miRNAs) are small non-coding RNA molecules that regulate gene expression by targeting specific mRNA species for degradation or interfering with translation. Specific miRNAs are key regulators of adipogenesis, and are expressed at different levels in adipose tissue from lean and obese mice. The degree of lipid accumulation and distribution of white adipose tissue differs between males and females, and it is unknown whether sex differences in adipose tissue-specific miRNA expression may contribute to this dimorphism. Typically, sex differences are attributed to hormones secreted from ovaries or testes. However, the sex chromosome complement (XX versus XY) is also a …

Distribution, Composition And Functions Of Gelatinous Tissues In Deep-Sea Fishes, Mackenzie E. Gerringer, Jeffrey C. Drazen, Thomas D. Linley, Adam P. Summers, Alan J. Jamieson, Paul H. Yancey

Biology

Many deep-sea fishes have a gelatinous layer, or subdermal extracellular matrix, below the skin or around the spine. We document the distribution of gelatinous tissues across fish families (approx. 200 species in ten orders), then review and investigate their composition and function. Gelatinous tissues from nine species were analysed for water content (96.53 ± 1.78% s.d.), ionic composition, osmolality, protein (0.39 ± 0.23%), lipid (0.69 ± 0.56%) and carbohydrate (0.61 ± 0.28%). Results suggest that gelatinous tissues are mostly extracellular fluid, which may allow animals to grow inexpensively. Further, almost all gelatinous tissues floated in cold seawater, thus their lower …

Targeted Calcium Influx Boosts Cytotoxic T Lymphocyte Function In The Tumour Microenvironment, Kyun-Do Kim, Seyeon Bae, Tara Capece, Hristina Nedelkovska, Rafael G. De Rubio, Alan V. Smrcka, Jun Chang-Duk, Jung Woojin, Byeonghak Park, Minsoo Kim, Tae-Il Kim, Minsoo Kim

Biology

Adoptive cell transfer utilizing tumour-targeting cytotoxic T lymphocytes (CTLs) is one of the most effective immunotherapies against haematological malignancies, but significant clinical success has not yet been achieved in solid tumours due in part to the strong immunosuppressive tumour microenvironment. Here, we show that suppression of CTL killing by CD4+CD25+Foxp+ regulatory T cell (Treg) is in part mediated by TGFβ-induced inhibition of inositol trisphosphate (IP3) production, leading to a decrease in T cell receptor (TCR)-dependent intracellular Ca2+ response. Highly selective optical control of Ca2+ signalling in adoptively transferred CTLs enhances T cell activation and IFN-γ production in vitro, leading to …