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In briefModes of reproduction across limbed vertebrates are diverse, but the molecular mechanisms required for the development and maintenance of reproductive tract tissue architecture are poorly understood. This paper describes gene expression changes across the regions of the reproductive tract of the adult female brown anole,Anolis sagrei. AbstractThe morphological diversity and functional role of the organs of the female reproductive system across tetrapods (limbed vertebrates) are relatively poorly understood. Although some features are morphologically similar, species-specific modification makes comparisons between species and inference about evolutionary origins challenging. In combination with the study of morphological changes, studying differences in gene expression in the adult reproductive system in diverse species can clarify the function of each organ. Here, we use the brown anole,Anolis sagrei, to study gene expression differences within the reproductive tract of the adult female. We generated gene expression profiles of four biological replicates of the three regions of the female reproductive tract, the infundibulum, glandular uterus, and nonglandular uterus, by RNA-sequencing. We aligned reads to the recently publishedA. sagreigenome and identified significantly differentially expressed genes between the regions using DESeq2. Each organ expressed approximately 14,600 genes, and comparison of gene expression profiles between organs revealed between 367 and 883 differentially expressed genes. We identify shared and region-specific transcriptional signatures for the three regions and compare gene expression in the brown anole reproductive tract to known gene expression patterns in other tetrapods. We find that genes in theHoxcluster have an anterior–posterior, collinear expression pattern as has been described in mammals. We also define a secretome for the glandular uterus. These data provide fundamental information for functional studies of the reproductive tract organs in the brown anole and an important phylogenetic anchor for comparative studies of the evolution of the female reproductive tract. 

Female reproduction in squamate reptiles (lizards and snakes) is highly diverse and mode of reproduction, clutch size, and reproductive tract morphology all vary widely across this group of  11,000 species. Recently, CRISPR genome editing techniques that require manipulation of the female reproductive anatomy have been developed in this group, making a more complete understanding of this anatomy essential. We describe the adult female reproductive anatomy of the model reptile the brown anole (Anolis sagrei). We show that the brown anole female reproductive tract has three distinct anteriorto- posterior regions, the infundibulum, the glandular uterus, and the nonglandular uterus. The infundibulum has a highly ciliated epithelial lip, a region where the epithelium is inverted so that cilia are present on the inside and outside of the tube. The glandular uterus has epithelial ducts that are patent with a lumen as well as acinar structures with a lumen. The nonglandular uterus has a heterogeneous morphology from anterior to posterior, with a highly folded, ciliated epithelium transitioning to a stratified squamous epithelium. This transition is accompanied by a loss of keratin-8 expression and together, these changes are similar to the morphological and gene expression changes that occur in the mammalian cervix. We recommend that description of the nonglandular uterus include the regional sub-specification of a “cervix” and “vagina” as this terminology change more accurately describes the morphology. Our data extend histological studies of reproductive organ morphology in reptiles and expand our understanding of the variation in reproductive system anatomy across squamates and vertebrates. 

Abstract Rates of human-induced environmental change continue increasing with human population size, potentially altering animal physiology and negatively affecting wildlife. Researchers often use glucocorticoid concentrations (hormones that can be associated with stressors) to gauge the impact of anthropogenic factors (e.g. urbanization, noise and light pollution). Yet, no general relationships between human-induced environmental change and glucocorticoids have emerged. Given the number of recent studies reporting baseline and stress-induced corticosterone (the primary glucocorticoid in birds and reptiles) concentrations worldwide, it is now possible to conduct large-scale comparative analyses to test for general associations between disturbance and baseline and stress-induced corticosterone across species. Additionally, we can control for factors that may influence context, such as life history stage, environmental conditions and urban adaptability of a species. Here, we take a phylogenetically informed approach and use data from HormoneBase to test if baseline and stress-induced corticosterone are valid indicators of exposure to human footprint index, human population density, anthropogenic noise and artificial light at night in birds and reptiles. Our results show a negative relationship between anthropogenic noise and baseline corticosterone for birds characterized as urban avoiders. While our results potentially indicate that urban avoiders are more sensitive to noise than other species, overall our study suggests that the relationship between human-induced environmental change and corticosterone varies across species and contexts; we found no general relationship between human impacts and baseline and stress-induced corticosterone in birds, nor baseline corticosterone in reptiles. Therefore, it should not be assumed that high or low levels of exposure to human-induced environmental change are associated with high or low corticosterone levels, respectively, or that closely related species, or even individuals, will respond similarly. Moving forward, measuring alternative physiological traits alongside reproductive success, health and survival may provide context to better understand the potential negative effects of human-induced environmental change.