Polyembryony in Maize: A Complex, Elusive, and Potentially Agronomical Useful Trait

Polyembryony (PE) is a rare phenomenon in cultivated plant species. Since nineteenth century, several reports have been published on PE in maize. Reports of multiple seedlings developing at embryonic level in laboratory and studies under greenhouse and field conditions have demonstrated the presence of PE in cultivated maize (Zea mays L.). Nevertheless, there is a lack of knowledge about this phenomenon; diverse genetic mechanisms controlling PE in maize have been proposed: Mendelian inheritance of a single gene, interaction between two genes and multiple genes are some of the proposed mechanisms. On the other hand, the presence of two or more embryos per seed confers higher nutrimental quality because these grains have more crude fat and lysine than normal maize kernels. As mentioned above, there is a necessity for more studies about PE maize in order to establish the genetic mechanism responsible for this phenomenon; on the other hand, previous studies showed that PE has potential to generate specialized maize varieties with yield potential and grain quality

The glitch-induced identity changes of PSR J1119-6127

We demonstrate that the high-magnetic field pulsar J1119-6127 exhibits three different types of behaviour in the radio band. Trailing the "normal" profile peak there is an "intermittent" peak and these components are flanked by two additional components showing very erratic "RRAT-like" emission. Both the intermittent and RRAT-like events are extremely rare and are preceded by a large amplitude glitch in the spin-down parameters. The post-glitch spin-down rate is smaller than the pre-glitch rate. This type of relaxation is very unusual for the pulsar population as a whole, but is observed in the glitch recovery of a RRAT. The abnormal emission behaviour in PSR J1119-6127 was observed up to three months after the epoch of the large glitch, suggestive of changes in the magnetospheric conditions during the fast part of the recovery process. We argue that both the anomalous recoveries and the emission changes could be related to reconfigurations of the magnetic field. Apart from the glitches, the spin-down of PSR J1119-6127 is relatively stable, allowing us to refine the measurement of the braking index (n=2.684\pm0.002) using more than 12 years of timing data. The properties of this pulsar are discussed in light of the growing evidence that RRATs do not form a distinct class of pulsar, but rather are a combination of different extreme emission types seen in other neutron stars. Different sub-classes of the RRATs can potentially be separated by calculating the lower limit on the modulation index of their emission. We speculate that if the abnormal behaviour in PSR J1119-6127 is indeed glitch induced then there might exist a population of neutron stars which only become visible in the radio band for a short duration in the immediate aftermath of glitch activity. These neutron stars will be visible in the radio band as sources that only emit some clustered pulses every so many years.Comment: 20 pages, 10 figures, Accepted for publication in MNRA

Survey data on the impact of COVID-19 on parental engagement across 23 countries

This data article describes the dataset of the International COVID-19 Impact on Parental Engagement Study (ICIPES). ICIPES is a collaborative effort of more than 20 institutions to investigate the ways in which, parents and caregivers built capacity engaged with children's learning during the period of social distancing arising from global COVID-19 pandemic. A series of data were collected using an online survey conducted in 23 countries and had a total sample of 4,658 parents/caregivers. The description of the data contained in this article is divided into two main parts. The first part is a descriptive analysis of all the items included in the survey and was performed using tables and figures. The second part refers to the construction of scales. Three scales were constructed and included in the dataset: 'parental acceptance and confidence in the use of technology', 'parental engagement in children's learning' and 'socioeconomic status'. The scales were created using Confirmatory Factor Analysis (CFA) and Multi-Group Confirmatory Analysis (MG-CFA) and were adopted to evaluate their cross-cultural comparability (i.e., measurement invariance) across countries and within sub-groups. This dataset will be relevant for researchers in different fields, particularly for those interested in international comparative education

Recurrent horizontal transfer identifies mitochondrial positive selection in a transmissible cancer

Abstract: Autonomous replication and segregation of mitochondrial DNA (mtDNA) creates the potential for evolutionary conflict driven by emergence of haplotypes under positive selection for ‘selfish’ traits, such as replicative advantage. However, few cases of this phenomenon arising within natural populations have been described. Here, we survey the frequency of mtDNA horizontal transfer within the canine transmissible venereal tumour (CTVT), a contagious cancer clone that occasionally acquires mtDNA from its hosts. Remarkably, one canine mtDNA haplotype, A1d1a, has repeatedly and recently colonised CTVT cells, recurrently replacing incumbent CTVT haplotypes. An A1d1a control region polymorphism predicted to influence transcription is fixed in the products of an A1d1a recombination event and occurs somatically on other CTVT mtDNA backgrounds. We present a model whereby ‘selfish’ positive selection acting on a regulatory variant drives repeated fixation of A1d1a within CTVT cells

Somatic evolution and global expansion of an ancient transmissible cancer lineage

Made available in DSpace on 2019-10-06T15:53:36Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-08-02GPD Charitable TrustLeverhulme TrustThe canine transmissible venereal tumor (CTVT) is a cancer lineage that arose several millennia ago and survives by “metastasizing” between hosts through cell transfer. The somatic mutations in this cancer record its phylogeography and evolutionary history. We constructed a time-resolved phylogeny from 546 CTVT exomes and describe the lineage's worldwide expansion. Examining variation in mutational exposure, we identify a highly context-specific mutational process that operated early in the cancer's evolution but subsequently vanished, correlate ultraviolet-light mutagenesis with tumor latitude, and describe tumors with heritable hyperactivity of an endogenous mutational process. CTVT displays little evidence of ongoing positive selection, and negative selection is detectable only in essential genes. We illustrate how long-lived clonal organisms capture changing mutagenic environments, and reveal that neutral genetic drift is the dominant feature of long-term cancer evolution.Transmissible Cancer Group Department of Veterinary Medicine University of CambridgeAnimal Management in Rural and Remote Indigenous Communities (AMRRIC)World VetsAnimal Shelter Stichting Dierenbescherming SurinameSikkim Anti-Rabies and Animal Health Programme Department of Animal Husbandry Livestock Fisheries and Veterinary Services Government of SikkimRoyal (Dick) School of Veterinary Studies Roslin Institute University of Edinburgh Easter Bush CampusConserLab Animal Preventive Medicine Department Faculty of Animal and Veterinary Sciences University of ChileCorozal Veterinary Hospital University of PanamáSt. George's UniversityNakuru District Veterinary Scheme LtdAnimal Medical CentreInternational Animal Welfare Training Institute UC Davis School of Veterinary MedicineCentro Universitário de Rio Preto (UNIRP)Department of Clinical and Veterinary Surgery São Paulo State University (UNESP)Ladybrand Animal ClinicVeterinary Clinic Sr. Dog'sWorld Vets Latin America Veterinary Training CenterNational Veterinary Research InstituteAnimal ClinicIntermunicipal Stray Animals Care Centre (DIKEPAZ)Animal Protection Society of SamoaFaculty of Veterinary Science University of ZuliaVeterinary Clinic BIOCONTROLFaculty of Veterinary Medicine School of Health Sciences University of ThessalyVeterinary Clinic El Roble Animal Healthcare Network Faculty of Animal and Veterinary Sciences University of ChileOnevetGroup Hospital Veterinário BernaUniversidade Vila VelhaVeterinary Clinic ZoovetservisÉcole Inter-états des Sciences et Médecine Vétérinaires de DakarDepartment of Small Animal Medicine Faculty of Veterinary Medicine Utrecht UniversityVetexpert Veterinary GroupVeterinary Clinic Lopez QuintanaClinique Veterinaire de Grand Fond Saint Gilles les BainsDepartment of Veterinary Sciences University of MessinaFacultad de Medicina Veterinaria y Zootecnia Universidad Autónoma del Estado de MéxicoSchool of Veterinary Medicine Universidad de las AméricasCancer Development and Innate Immune Evasion Lab Champalimaud Center for the UnknownTouray and Meyer Vet ClinicHillside Animal HospitalKampala Veterinary SurgeryAsavet Veterinary CharitiesVets Beyond BordersFaculty of Veterinary Medicine Autonomous University of YucatanLaboratorio de Patología Veterinaria Universidad de CaldasInterdisciplinary Centre of Research in Animal Health (CIISA) Faculty of Veterinary Medicine University of LisbonFour Paws InternationalHelp in SufferingVeterinary Clinic Dr José RojasDepartment of Biotechnology Balochistan University of Information Technology Engineering and Management SciencesCorozal Veterinary ClinicVeterinary Clinic VetmasterState Hospital of Veterinary MedicineJomo Kenyatta University of Agriculture and TechnologyLaboratory of Biomedicine and Regenerative Medicine Department of Clinical Sciences Faculty of Animal and Veterinary Sciences University of ChileFaculty of Veterinary and Agricultural Sciences University of MelbourneAnimal Anti Cruelty LeagueClinical Sciences Department Faculty of Veterinary Medicine BucharestDepartment of Pathology Faculty of Veterinary Medicine Ankara UniversityFaculty of Veterinary Sciences National University of AsuncionLilongwe Society for Protection and Care of Animals (LSPCA)Wellcome Sanger InstituteDepartment of Cellular and Molecular Medicine University of California San DiegoDepartment of Clinical and Veterinary Surgery São Paulo State University (UNESP)Leverhulme Trust: 102942/Z/13/

Return of the Big Glitcher: NICER timing and glitches of PSR J0537−6910

International audiencePSR J0537−6910, also known as the Big Glitcher, is the most prolific glitching pulsar known, and its spin-induced pulsations are only detectable in X-ray. We present results from analysis of 2.7 yr of NICER timing observations, from 2017 August to 2020 April. We obtain a rotation phase-connected timing model for the entire time span, which overlaps with the third observing run of LIGO/Virgo, thus enabling the most sensitive gravitational wave searches of this potentially strong gravitational wave-emitting pulsar. We find that the short-term braking index between glitches decreases towards a value of 7 or lower at longer times since the preceding glitch. By combining NICER and RXTE data, we measure a long-term braking index n = −1.25 ± 0.01. Our analysis reveals eight new glitches, the first detected since 2011, near the end of RXTE, with a total NICER and RXTE glitch activity of |$8.88\times 10^{-7}\, \mathrm{yr^{-1}}$|⁠. The new glitches follow the seemingly unique time-to-next-glitch–glitch-size correlation established previously using RXTE data, with a slope of |$5\, \rm {d} \, \mu \mathrm{Hz}^{-1}$|⁠. For one glitch around which NICER observes 2 d on either side, we search for but do not see clear evidence of spectral nor pulse profile changes that may be associated with the glitch