The evolution of the placenta from a non-placental ancestor causes a shift of maternal investment from pre- to post-fertilization, creating a venue for parent-offspring conflicts during pregnancy. ...Theory predicts that the rise of these conflicts should drive a shift from a reliance on pre-copulatory female mate choice to polyandry in conjunction with post-zygotic mechanisms of sexual selection. This hypothesis has not yet been empirically tested. Here we apply comparative methods to test a key prediction of this hypothesis, which is that the evolution of placentation is associated with reduced pre-copulatory female mate choice. We exploit a unique quality of the livebearing fish family Poeciliidae: placentas have repeatedly evolved or been lost, creating diversity among closely related lineages in the presence or absence of placentation. We show that post-zygotic maternal provisioning by means of a placenta is associated with the absence of bright coloration, courtship behaviour and exaggerated ornamental display traits in males. Furthermore, we found that males of placental species have smaller bodies and longer genitalia, which facilitate sneak or coercive mating and, hence, circumvents female choice. Moreover, we demonstrate that post-zygotic maternal provisioning correlates with superfetation, a female reproductive adaptation that may result in polyandry through the formation of temporally overlapping, mixed-paternity litters. Our results suggest that the emergence of prenatal conflict during the evolution of the placenta correlates with a suite of phenotypic and behavioural male traits that is associated with a reduced reliance on pre-copulatory female mate choice.
This open access book shows policymakers which initiatives work when responding to the increasing diversity in cities, towns and neighborhood's. In recent times, policymakers have grappled with ways ...of responding to this increase, which has resulted in a plethora of policy initiatives, some more effective than others. Bringing together a large amount of research and evidence-based policy recommendations, this book offers both a sense of strategic direction as well as more specific, actionable advice. It brings together a remarkable mixture of policy areas that touch upon issues of diversity, immigration policy, education, and labour policy. It is of benefit and importance to all those making policies for a country with increasing immigration.
Cellular senescence is the irreversible arrest of normally dividing cells and is driven by the cell cycle inhibitors Cdkn2a, Cdkn1a, and Trp53. Senescent cells are implicated in chronic diseases and ...tissue repair through their increased secretion of pro‐inflammatory factors known as the senescence‐associated secretory phenotype (SASP). Here, we use spatial transcriptomics and single‐cell RNA sequencing (scRNAseq) to demonstrate that cells displaying senescent characteristics are “transiently” present within regenerating skeletal muscle and within the muscles of D2‐mdx mice, a model of Muscular Dystrophy. Following injury, multiple cell types including macrophages and fibrog–adipogenic progenitors (FAPs) upregulate senescent features such as senescence pathway genes, SASP factors, and senescence‐associated beta‐gal (SA‐β‐gal) activity. Importantly, when these cells were removed with ABT‐263, a senolytic compound, satellite cells are reduced, and muscle fibers were impaired in growth and myonuclear accretion. These results highlight that an “acute” senescent phenotype facilitates regeneration similar to skin and neonatal myocardium.
Higher level relationships among placental mammals, as well as the historical biogeography and morphological diversification of this group, remain unclear. Here we analyse independent molecular data ...sets, having aligned lengths of DNA of 5,708 and 2,947 base pairs, respectively, for all orders of placental mammals. Phylogenetic analyses resolve placental orders into four groups: Xenarthra, Afrotheria, Laurasiatheria, and Euarchonta plus Glires. The first three groups are consistently monophyletic with different methods of analysis. Euarchonta plus Glires is monophyletic or paraphyletic depending on the phylogenetic method. A unique nine-base-pair deletion in exon 11 of the BRCA1 gene provides additional support for the monophyly of Afrotheria, which includes proboscideans, sirenians, hyracoids, tubulidentates, macroscelideans, chrysochlorids and tenrecids. Laurasiatheria contains cetartiodactyls, perissodactyls, carnivores, pangolins, bats and eulipotyphlan insectivores. Parallel adaptive radiations have occurred within Laurasiatheria and Afrotheria. In each group, there are aquatic, ungulate and insectivore-like forms.
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