Investigating magmatic processes in the early Solar System using the Cl isotopic systematics of eucrites

Generally, terrestrial rocks, martian and chondritic meteorites exhibit a relatively narrow range in bulk and apatite Cl isotope compositions, with δ37Cl (per mil deviation from standard mean ocean chloride) values between − 5.6 and + 3.8 ‰. Lunar rocks, however, have more variable bulk and apatite δ37Cl values, ranging from ∼ − 4 to + 40 ‰. As the Howardite-Eucrite-Diogenite (HED) meteorites represent the largest suite of crustal and sub-crustal rocks available from a differentiated basaltic asteroid (4 Vesta), studying them for their volatiles may provide insights into planetary differentiation processes during the earliest Solar System history. Here the abundance and isotopic composition of Cl in apatite were determined for seven eucrites representing a broad range of textural and petrological characteristics. Apatite Cl abundances range from ∼ 25 to 4900 ppm and the δ37Cl values range from − 3.98 to + 39.2 ‰. Samples with lower apatite H2O contents were typically also enriched in 37Cl but no systematic correlation between δ37Cl and δD values was observed across samples. Modelled Rayleigh fractionation and a strong positive correlation between bulk δ66Zn and apatite δ37Cl support the hypothesis that Cl degassed as metal chlorides from eucritic magmas, in a hydrogen-poor environment. In the case of lunar samples, it has been noted that δ37Cl values of apatite positively correlate with bulk La/Yb ratio. Interestingly, most eucrites show a negative correlation with bulk La/Yb ratio. Recently, isotopically light Cl values have been suggested to record the primary solar nebular signature. If this is the case then 4 Vesta, which accreted rapidly and early in Solar System history, could also record this primary nebular signature corresponding to the lightest Cl values measured here. The significant variation in Cl isotope composition observed within the eucrites are likely related to degassing of metal chlorides

Preserving accuracy in GenBank

GenBank, the public repository for nucleotide and protein sequences, is a critical resource for molecular biology, evolutionary biology, and ecology. While some attention has been drawn to sequence errors, common annotation errors also reduce the value of this database. In fact, for organisms such as fungi, which are notoriously difficult to identify, up to 20% of DNA sequence records may have erroneous lineage designations in GenBank. Gene function annotation in protein sequence databases is similarly error-prone. Because identity and function of new sequences are often determined by bioinformatic analyses, both types of errors are propagated into new accessions, leading to long-term degradation of the quality of the database. Currently, primary sequence data are annotated by the authors of those data, and can only be reannotated by the same authors. This is inefficient and unsustainable over the long term as authors eventually leave the field. Although it is possible to link third-party databases to GenBank records, this is a short-term solution that has little guarantee of permanence. Similarly, the current third-party annotation option in GenBank (TPA) complicates rather than solves the problem by creating an identical record with a new annotation, while leaving the original record unflagged and unlinked to the new record. Since the origin of public zoological and botanical specimen collections, an open system of cumulative annotation has evolved, whereby the original name is retained, but additional opinion is directly appended and used for filing and retrieval. This was needed as new specimens and analyses allowed for reevaluation of older specimens and the original depositors became unavailable. The time has come for the public sequence database to incorporate a community-curated, cumulative annotation process that allows third parties to improve the annotations of sequences when warranted by published peer-reviewed analyses.Fil: Bidartondo, Martin I.. Imperial College London; Reino Unido. Royal Botanic Gardens; Reino UnidoFil: Bruns, Thomas D.. University of California at Berkeley; Estados UnidosFil: Blackwell, Meredith. Louisiana State University; Estados UnidosFil: Edwards, Ivan. University of Michigan; Estados UnidosFil: Taylor, Andy F. S.. Swedish University of Agricultural Sciences; SueciaFil: Bianchinotti, Maria Virginia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina. Universidad Nacional del Sur; ArgentinaFil: Padamsee, Mahajabeen. University of Minnesota; Estados UnidosFil: Callac, Philippe. Institut National de la Recherche Agronomique; FranciaFil: Lima, Nelson. Universidade do Minho; PortugalFil: White, Merlin M.. Boise State University; Estados UnidosFil: Barreau Daly, Camila. Centre National de la Recherche Scientifique; Francia. Institut National de la Recherche Agronomique; FranciaFil: Juncai, M. A.. Chinese Academy of Sciences; República de ChinaFil: Buyck, Bart. Museum National d'Histoire Naturelle; FranciaFil: Rabeler, Richard K.. University of Michigan; Estados UnidosFil: Liles, Mark R.. Auburn University; Estados UnidosFil: Estes, Dwayne. Austin Peay State University; Estados UnidosFil: Carter, Richard. Valdosta State University; Estados UnidosFil: Herr Jr., J. M.. University of South Carolina; Estados UnidosFil: Chandler, Gregory. University of North Carolina; Estados UnidosFil: Kerekes, Jennifer. University of California at Berkeley; Estados UnidosFil: Cruse Sanders, Jennifer. Salem College Herbarium; Estados UnidosFil: Galán Marquez, R.. Universidad de Alcalá; EspañaFil: Horak, Egon. Zurich Herbarium; SuizaFil: Fitzsimons, Michael. University of Chicago; Estados UnidosFil: Döering, Heidi. Royal Botanic Gardens; Reino UnidoFil: Yao, Su. China Center of Industrial Culture Collection; ChinaFil: Hynson, Nicole. University of California at Berkeley; Estados UnidosFil: Ryberg, Martin. University Goteborg; SueciaFil: Arnold, A. E.. University of Arizona; Estados UnidosFil: Hughes, Karen. University of Tennessee; Estados Unido