Timing and regulation of cohesion depletion during mammalian oogenesis

PhD ThesisSexual reproduction depends on the transmission of exactly one copy of each chromosome by the maternal and paternal gametes. This is accomplished during meiosis when diploid progenitors undergo two consecutive rounds of chromosome segregation following a single round of DNA replication. In most organisms, this relies on the establishment of bivalent chromosomes consisting of replicated parental homologues physically linked at sites of meiotic recombination. In female mammals, bivalents are formed during fetal development when the lifetime stock of primordial-stage oocytes is established. However, they are not resolved until shortly before ovulation. Extending this period beyond ~35 years results in a dramatic increase in embryo aneuploidy. Depletion of the lifetime stock of oocytes during ageing culminates in menopause. Our previous studies indicate that Rec8-containing cohesin complexes also become depleted from oocyte chromosomes during female ageing. Consistent with cohesin’s role in maintaining chromosome structure, depletion of Rec8 is associated with destabilisation of bivalents chromosomes. Nevertheless, the mechanisms and timing of cohesin depletion remain unknown. Here, I investigated the possibility that age-related cohesin depletion is a consequence of leaky inhibition of the protease separase, which cleaves Rec8 during anaphase. I found that oocyte-specific deletion of separase did not prevent depletion of oocyte cohesin during female ageing. I, therefore, conclude that age-related depletion occurs by a separase-independent mechanism. I next investigated the timing, during oogenesis, at which cohesin loss occurs. I found that cohesin is predominantly lost at the primordial stage before oocytes are recruited for growth. In addition, using an oocyte-specific deletion of Pten, I determined that this occurs independently of the decline in the ovarian stock of primordial-stage oocytes. Together, these results indicate that age-related cohesin depletion occurs at the primordial stage by a separase-independent mechanism. Other possible of mechanisms of cohesin depletion include protein damage and/or age-related deterioration of chromatin structure. From a clinical perspective, my work suggests that “rejuvenation’ of fertility by activating the residual pool of primordial oocytes is unlikely to be successful in older women.Dame Margaret Barbour and Barbour foundatio

Elevational richness patterns of sphingid moths support area effects over climatic drivers in a near‐global analysis

Not sure if this is the pre-refereed or final submitted version.Aim We test hypotheses on the environmental control of elevational richness patterns of sphingid moths for their global applicability and generality. Specifically, we compare effects of area with climate‐related drivers, such as primary productivity and temperature, while also considering direct effects of precipitation. Major taxa Sphingid moths (Lepidoptera). Location Eighty‐six mountain ranges of the Old World and the Australia/Pacific region, from Scandinavia and Siberia through the African and Australasian tropics to South Africa and Southern Australia. Methods We used a large compilation of point locality records for 744 species, in addition to fine‐grained range maps derived from species distribution modelling of these records, to characterize the elevational pattern of species richness in 86 custom‐delineated mountain regions. For both types of data, we compared the effects of environmental drivers on richness by comparing standardized coefficients of multivariate models for pooled data after accounting for between‐region variation in richness. Results We observed varying patterns of elevational richness across the research region, with a higher prevalence of midpeaks in arid regions. We found overwhelming support for area as a main determinant of richness, modulated by temperature and productivity, whereas we detected no effect of precipitation. Main conclusions Area, productivity and temperature are the main environmental predictors explaining a large proportion of variability in sphingid richness. This is consistent not only with other elevational studies, but also with empirical and theoretical biodiversity research in a non‐elevational context (with the caveat of some unresolved issues in elevational area effects). However, distinct differences in elevational patterns remain even within the same mountain ranges when comparing with other Lepidoptera, that is, geometrid moths, which highlights the importance of understanding higher clade differentiation in ecological responses, within insects and in other groups.© 2019 John Wiley & Sons Ltd. This is the pre-peer reviewed version of the following article: Bärtschi, F, McCain, CM, Ballesteros‐Mejia, L, Kitching, IJ, Beerli, N, Beck, J. Elevational richness patterns of sphingid moths support area effects over climatic drivers in a near‐global analysis. Global Ecol Biogeogr. 2019; 28: 917– 927. https://doi.org/10.1111/geb.12903, which has been published in final form at doi:10.1111/geb.12903. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.

Economic costs of biological invasions in Ecuador:the importance of the Galapagos Islands

Biological invasions, as a result of human intervention through trade and mobility, are the second biggest cause of biodiversity loss. The impacts of invasive alien species (IAS) on the environment are well known, however, economic impacts are poorly estimated, especially in mega-diverse countries where both economic and ecological consequences of these effects can be catastrophic. Ecuador, one of the smallest mega-diverse countries, lacks a comprehensive description of the economic costs of IAS within its territory. Here, using "InvaCost", a public database that compiles all recorded monetary costs associated with IAS from English and Non-English sources, we investigated the economic costs of biological invasions. We found that between 1983 and 2017, the reported costs associated with biological invasions ranged between US$86.17 million (when considering only the most robust data) and US$626 million (when including all cost data) belonging to 37 species and 27 genera. Furthermore, 99% of the recorded cost entries were from the Galapagos Islands. From only robust data, the costliest identified taxonomic group was feral goats (Capra hircus; US$20 million), followed by Aedes mosquitoes (US$2.14 million) while organisms like plant species from the genus Rubus, a parasitic fly (Philornis downsi), black rats (Rattus rattus) and terrestrial gastropods (Achatina fulica) represented less than US2 million each. Costs of "mixed-taxa" (i.e. plants and animals) represented the highest (61% of total robust costs; US52.44 million). The most impacted activity sector was the national park authorities, which spent about US$84 million. Results from robust data also revealed that management expenditures were the major type of costs recorded in the Galapagos Islands; however, costs reported for medical losses related to Aedes mosquitoes causing dengue fever in mainland Ecuador would have ranked first if more detailed information had allowed us to categorize them as robust data. Over 70% of the IAS reported for Ecuador did not have reported costs. These results suggest that costs reported here are a massive underestimate of the actual economic toll of invasions in the country

A global checklist of the Bombycoidea (Insecta: Lepidoptera)

This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. The attached file is the published pdf plus supplementary data file.NHM Repositor

How climatic variability is linked to the spatial distribution of range sizes: seasonality versus climate change velocity in sphingid moths

Aim: To map the spatial variation of range sizes within sphingid moths, and to test hypotheses on its environmental control. In particular, we investigate effects of climate change velocity since the Pleistocene and the mid-Holocene, temperature and precipitation seasonality, topography, Pleistocene ice cover, and available land area. Location: Old World and Australasia, excluding smaller islands. Methods: We used fine-grained range maps (based on expert-edited distribution modelling) for all 972 sphingid moth species in the research region and calculated, at a grain size of 100 km, the median of range sizes of all species that co-occur in a pixel. Climate, topography and Pleistocene ice cover data were taken from publicly available sources. We calculated climate change velocities (CCV) for the last 21ky as well as 6ky. We compared the effects of seasonality and CCV on median range sizes with spatially explicit models while accounting for effects of elevation range, glaciation history and available land area. Results: Range sizes show a clear spatial pattern, with highest median values in deserts and arctic regions and lowest values in isolated tropical regions. Range sizes were only weakly related to absolute latitude (predicted by Rapoport’s effect), but there was a strong north-south pattern of range size decline. Temperature seasonality emerged as the strongest environmental correlate of median range size, in univariate as well as multivariate models, whereas effects of CCV were weak and unstable for both time periods. These results were robust to variations in the parameters in alternative analyses, among them multivariate CCV. Main conclusions: Temperature seasonality is a strong correlate of spatial range size variation, while effects of longer-term temperature change, as captured by CCV, received much weaker support.The attached document is the author(’s’) final accepted/submitted version of the journal article. You are advised to consult the publisher’s version if you wish to cite from itNHM Repositor

Economic costs of invasive rodents worldwide : the tip of the iceberg

ACKNOWLEDGEMENTS We are extremely grateful to the organizers of the InvaCost workshop that allowed the genesis of this project, as well as to all contacted people who kindly answered to our requests for information about the costs of invasive rodents. We thank L. Nuninger and C. Assailly for their work in the initial project, and María Angulo and Nuria Cerdá for their help in generating the Fig. 3. Last, the authors thank Dr. Steffen Oppel and another anonymous reviewer for their thorough revision of the article which greatly improved it. Funding Information: This work was supported by the French National Research Agency (ANR-14-CE02-0021) and the BNP-Paribas Foundation Climate Initiative for funding the Invacost project which allowed the construction of the InvaCost database. This work was initiated following a workshop funded by the AXA Research Fund Chair of Invasion Biology. This research was also funded through the 2017-2018 Belmont Forum and BiodivERsA joint call for research proposals, under the BiodivScen ERA-Net COFUND programme. Funds for Elena Angulo and Liliana Ballesteros-Mejia came from the AXA Research Fund Chair of Invasion Biology of University Paris Saclay. Christophe Diagne was funded by the BiodivERsA-Belmont Forum Project ‘‘Alien Scenarios’’ (BMBF/PT DLR 01LC1807C). Ross N. Cuthbert received funding from the Leverhulme Trust (ECF-2021-001). Thomas W. Bodey received funding from the European Union’s Horizon 2020 research and innovation programme Marie Skłodowska-Curie fellowship (Grant No. 747120). Jean Fantle-Lepczyk received travel support to attend the Invacost workshop from Auburn University School of Forestry and Wildlife Sciences. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

The economic costs of biological invasions in Central and South America: a first regional assessment

Invasive alien species are responsible for a high economic impact on many sectors worldwide. Nevertheless, there is a scarcity of studies assessing these impacts in Central and South America. Investigating costs of invasions is important to motivate and guide policy responses by increasing stakeholders’ awareness and identifying action priorities. Here, we used the InvaCost database to investigate (i) the geographical pattern of biological invasion costs across the region; (ii) the monetary expenditure across taxa and impacted sectors; and (iii) the taxa responsible for more than 50% of the costs (hyper-costly taxa) per impacted sector and type of costs. The total of reliable and observed costs reported for biological invasions in Central and South America was USD 102.5 billion between 1975 and 2020, but about 90% of the total costs were reported for only three countries (Brazil, Argentina and Colombia). Costs per species were associated with geographical regions (i.e., South America, Central America and Islands) and with the area of the countries in km2. Most of the expenses were associated with damage costs (97.8%), whereas multiple sectors (77.4%), agriculture (15%) and public and social welfare (4.2%) were the most impacted sectors. Aedes spp. was the hyper-costly taxon for the terrestrial environment (costs of USD 25 billion) and water hyacinth (Eichhornia crassipes) was the hyper-costly taxon for the aquatic environment (USD 179.9 million). Six taxa were classified as hyper-costly for at least one impacted sector and two taxa for at least one type of cost. In conclusion, invasive alien species caused billions of dollars of economic burden in Central and South America, mainly in large countries of South America. Costs caused by invasive alien species were unevenly distributed across countries, impacted sectors, types of costs and taxa (hyper-costly taxa). These results suggest that impacted sectors should drive efforts to manage the species that are draining financial sources.info:eu-repo/semantics/publishedVersio

A diversification relay race from Caribbean-Mesoamerica to the Andes: historical biogeography of Xylophanes hawkmoths

The regions of the Andes and Caribbean-Mesoamerica are both hypothesized to be the cradle for many Neotropical lineages, but few studies have fully investigated the dynamics and interactions between Neotropical bioregions. The New World hawkmoth genus Xylophanes is the most taxonomically diverse genus in the Sphingidae, with the highest endemism and richness in the Andes and Caribbean-Mesoamerica. We integrated phylogenomic and DNA barcode data and generated the first time-calibrated tree for this genus, covering 93.8% of the species diversity. We used event-based likelihood ancestral area estimation and biogeographic stochastic mapping to examine the speciation and dispersal dynamics of Xylophanes across bioregions. We also used trait-dependent diversification models to compare speciation and extinction rates of lineages associated with different bioregions. Our results indicate that Xylophanes originated in Caribbean-Mesoamerica in the Late Miocene, and immediately diverged into five major clades. The current species diversity and distribution of Xylophanes can be explained by two consecutive phases. In the first phase, the highest Xylophanes speciation and emigration rates occurred in the Caribbean-Mesoamerica, and the highest immigration rates occurred in the Andes, whereas in the second phase the highest immigration rates were found in Amazonia, and the Andes had the highest speciation and emigration rates.Copyright © 2022, The Authors. This document is the author’s final accepted version of the journal article. You are advised to consult the published version if you wish to cite from it.NHM Repositor