Evolution of Embryo Implantation Was Enabled by the Origin of Decidual Stromal Cells in Eutherian Mammals

Mammalian pregnancy evolved in the therian stem lineage, that is, before the common ancestor of marsupials and eutherian (placental) mammals. Ancestral therian pregnancy likely involved a brief phase of attachment between the fetal and maternal tissues followed by parturition—similar to the situation in most marsupials including the opossum. In all eutherians, however, embryo attachment is followed by implantation, allowing for a stable fetal–maternal interface and an extended gestation. Embryo attachment induces an attachment reaction in the uterus that is homologous to an inflammatory response. Here, we elucidate the evolutionary mechanism by which the ancestral inflammatory response was transformed into embryo implantation in the eutherian lineage. We performed a comparative uterine transcriptomic and immunohistochemical study of three eutherians, armadillo (Dasypus novemcinctus), hyrax (Procavia capensis), and rabbit (Oryctolagus cuniculus); and one marsupial, opossum (Monodelphis domestica). Our results suggest that in the eutherian lineage, the ancestral inflammatory response was domesticated by suppressing one of its modules detrimental to pregnancy, namely, neutrophil recruitment by cytokine IL17A. Further, we propose that this suppression was mediated by decidual stromal cells, a novel cell type in eutherian mammals. We tested a prediction of this model in vitro and showed that decidual stromal cells can suppress the production of IL17A from helper T cells. Together, these results provide a mechanistic understanding of early stages in the evolution of eutherian pregnancy.

Patch use and site selection by a rock hyrax (Procavia capensis) in a human-dominated landscape in the West Bank of Palestine

Populations of rock hyraxes (Procavia capensis) increasingly occur in urbanizing areas of the Palestinian West Bank, and throughout the Middle East, in part due to construction methods that create rock piles that shelter hyraxes. We quantified activity densities of the hyraxes, environmental variables, and plant cover at four sites that differ in urbanization. The highest numbers occurred in the most urban site and peaked in June and October, with hyraxes traveling farther distances from their dens late in the season (October). Sites with higher activity densities of hyraxes had higher vapor pressures, signifying more mesic conditions. Thus, urbanization aids the expansion of hyraxes.

Spatial genetic structure in the rock hyrax (Procavia capensis) across the Namaqualand and western Fynbos areas of South Africa — a mitochondrial and microsatellite perspective

The interplay between biotic and abiotic environments is increasingly recognized as a major determinant of spatial genetic patterns. Among spatial genetic studies, saxicolous or rock-dwelling species remain underrepresented in spite of their strict dependence on landscape structure. Here we investigated patterns and processes operating at different spatial (fine and regional scales) and time scales (using mitochondrial and microsatellite markers) in the rock hyrax (Procavia capensis (Pallas, 1766)). Our focus was on the western seaboard of South Africa and included two recognized biodiversity hotspots (Cape Floristic Region and Succulent Karoo). At fine spatial scale, significant genetic structure was present between four rocky outcrops in an isolated population, likely driven by the social system of this species. At a broader spatial scale, ecological dependence on rocky habitat and population-level processes, in conjunction with landscape structure, appeared to be the main drivers of genetic diversity and structure. Large areas devoid of suitable rocky habitat (e.g., the Knersvlakte, Sandveld, and Cape Flats, South Africa) represent barriers to gene flow in the species, although genetic clusters closely follow climatic, geological, and phytogeographic regions, possibly indicating ecological specialization or adaptation as contributing factors enforcing isolation. Taken together, our study highlights the need to consider both intrinsic and extrinsic factors when investigating spatial genetic structures within species.

Complex evolution of porcine endogenous retroviruses

Background: Porcine endogenous retroviruses (PERVs) are proviruses that can replicate in human cells. However, the evolutionary process leading to the generation of modern PERVs is not well understood.Results: We mined 14 pig genomes and other available 304 mammalian genomes in silico, which led to the documentation of 185 full-length PERVs. Notably, we found two novel ERVs in the lesser Egyptian jerboa ( Jaculus jaculus ) and rock hyrax ( Procavia capensis ) named ERV-Gamma-Jja and ERV-Gamma-Pca, respectively, which were the source of the modern PERVs. Phylogenetic analyses provided evidence for the multiple origins of PERVs involving hosts of rodents, rock hyrax, and pigs. Conclusion: These new findings help us to understand the complex evolution of the modern PERVs.

A new species of Versicorpus Deschodt, Davis & Scholtz, 2011 (Scarabaeidae: Scarabaeinae: Byrrhidiini) from the Brandberg Mountain, Namibia

The recently described dung beetle tribe Byrrhidiini currently comprises seven genera and nineteen species (Davis et al. 2019). During a recent collecting expedition to the Brandberg Mountain [S21.11° E14.69°] in Namibia, a single male specimen, together with various disarticulated body parts of a new species belonging to this tribe were collected. It was found amongst dried hyrax (Procavia capensis) dung pellets between large granite boulders. This new species clearly fits the current definition of the genus Versicorpus Deschodt, Davis & Scholtz, 2011. This raises the number of the constituent species of Versicorpus to three and that for Byrrhidiini to twenty.