Recombination dynamics of a human Y-chromosomal palindrome:rapid GC-biased gene conversion, multi-kilobase conversion tracts, and rare inversions

The male-specific region of the human Y chromosome (MSY) includes eight large inverted repeats (palindromes) in which arm-to-arm similarity exceeds 99.9%, due to gene conversion activity. Here, we studied one of these palindromes, P6, in order to illuminate the dynamics of the gene conversion process. We genotyped ten paralogous sequence variants (PSVs) within the arms of P6 in 378 Y chromosomes whose evolutionary relationships within the SNP-defined Y phylogeny are known. This allowed the identification of 146 historical gene conversion events involving individual PSVs, occurring at a rate of 2.9-8.4×10(-4) events per generation. A consideration of the nature of nucleotide change and the ancestral state of each PSV showed that the conversion process was significantly biased towards the fixation of G or C nucleotides (GC-biased), and also towards the ancestral state. Determination of haplotypes by long-PCR allowed likely co-conversion of PSVs to be identified, and suggested that conversion tract lengths are large, with a mean of 2068 bp, and a maximum in excess of 9 kb. Despite the frequent formation of recombination intermediates implied by the rapid observed gene conversion activity, resolution via crossover is rare: only three inversions within P6 were detected in the sample. An analysis of chimpanzee and gorilla P6 orthologs showed that the ancestral state bias has existed in all three species, and comparison of human and chimpanzee sequences with the gorilla outgroup confirmed that GC bias of the conversion process has apparently been active in both the human and chimpanzee lineages

Drivers of Cape Verde archipelagic endemism in keyhole limpets

Oceanic archipelagos are the ideal setting for investigating processes that shape species assemblages. Focusing on keyhole limpets, genera Fissurella and Diodora from Cape Verde Islands, we used an integrative approach combining molecular phylogenetics with ocean transport simulations to infer species distribution patterns and analyse connectivity. Dispersal simulations, using pelagic larval duration and ocean currents as proxies, showed a reduced level of connectivity despite short distances between some of the islands. It is suggested that dispersal and persistence driven by patterns of oceanic circulation favouring self-recruitment played a primary role in explaining contemporary species distributions. Mitochondrial and nuclear data revealed the existence of eight Cape Verde endemic lineages, seven within Fissurella, distributed across the archipelago, and one within Diodora restricted to Boavista. The estimated origins for endemic Fissurella and Diodora were 10.2 and 6.7 MY, respectively. Between 9.5 and 4.5 MY, an intense period of volcanism in Boavista might have affected Diodora, preventing its diversification. Having originated earlier, Fissurella might have had more opportunities to disperse to other islands and speciate before those events. Bayesian analyses showed increased diversification rates in Fissurella possibly promoted by low sea levels during Plio-Pleistocene, which further explain differences in species richness between both genera.FCT - Portuguese Science Foundation [SFRH/BPD/109685/2015, SFRH/BPD/111003/2015]; Norte Portugal Regional Operational Program (NORTE), under the PORTUGAL Partnership Agreement, through the European Regional Development Fund (ERDF) [MARINFO - NORTE-01-0145-FEDER-000031]info:eu-repo/semantics/publishedVersio

Multi-messenger observations of a binary neutron star merger

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

Determinants of the exclusive breastfeeding abandonment: psychosocial factors

OBJECTIVE To assess the determinants of exclusive breastfeeding abandonment. METHODS Longitudinal study based on a birth cohort in Viçosa, MG, Southeastern Brazil. In 2011/2012, 168 new mothers accessing the public health network were followed. Three interviews, at 30, 60, and 120 days postpartum, with the new mothers were conducted. Exclusive breastfeeding abandonment was analyzed in the first, second, and fourth months after childbirth. The Edinburgh Postnatal Depression Scale was applied to identify depressive symptoms in the first and second meetings, with a score of ≥ 12 considered as the cutoff point. Socioeconomic, demographic, and obstetric variables were investigated, along with emotional conditions and the new mothers’ social network during pregnancy and the postpartum period. RESULTS The prevalence of exclusive breastfeeding abandonment at 30, 60, and 120 days postpartum was 53.6% (n = 90), 47.6% (n = 80), and 69.6% (n = 117), respectively, and its incidence in the fourth month compared with the first was 48.7%. Depressive symptoms and traumatic delivery were associated with exclusive breastfeeding abandonment in the second month after childbirth. In the fourth month, the following variables were significant: lower maternal education levels, lack of homeownership, returning to work, not receiving guidance on breastfeeding in the postpartum period, mother’s negative reaction to the news of pregnancy, and not receiving assistance from their partners for infant care. CONCLUSIONS Psychosocial and sociodemographic factors were strong predictors of early exclusive breastfeeding abandonment. Therefore, it is necessary to identify and provide early treatment to nursing mothers with depressive symptoms, decreasing the associated morbidity and promoting greater duration of exclusive breastfeeding. Support from health professionals, as well as that received at home and at work, can assist in this process

Turnip yellow mosaic virus in Chinese cabbage in Spain: Commercial seed transmission and molecular characterization

[EN] Seed transmission of Turnip yellow mosaic virus (TYMV, genus Tymovirus) was evaluated in the whole seeds and seedlings that emerged from three commercial Chinese cabbage (Brassica pekinensis) seed batches. Seedlings in the cotyledon stage and adult plants were assayed for TYMV by DAS-ELISA and confirmed by RT-PCR. The proportion of whole seeds infected with TYMV was at least 0.15 %. The seeds of the three seed batches were grown in Petri dishes, and surveyed in the cotyledon stage in trays that contained a peat:sand mixture grown in greenhouses or growth chambers, which were analysed in the cotyledon and adult stages. The seed-to-seedling transmission rate ranged from 2.5 % to 2.9 % in two different seed batches (lot-08 and lot-09, respectively). Spanish isolates derived from turnip (Sp-03) and Chinese cabbage (Sp-09 and Sp-13), collected in 2003, 2009 and 2013 in two different Spanish regions, were molecularly characterised by analysing the partial nucleotide sequences of three TYMV genome regions: partial RNA-dependent RNA polymerase (RdRp), methyltransferase (MTR) and coat protein (CP) genes. Phylogenetic analyses showed that the CP gene represented two different groups: TYMV-1 and TYMV-2. The first was subdivided into three subclades: European, Australian and Japanese. Spanish isolate Sp-03 clustered together with European TYMV group, whereas Sp-09 and Sp-13 grouped with the Japanese TYMV group, and all differed from group TYMV-2. The sequences of the three different genomic regions examined clustered into the same groups. The results suggested that Spanish isolates grouped according to the original hosts from which they were isolated. The inoculation of the Spanish TYMV isolates to four crucifer plants species (turnip, broccoli, Brunswick cabbage and radish) revealed that all the isolates infected turnip with typical symptoms, although differences were observed in other hosts.Alfaro Fernández, AO.; Serrano, A.; Tornos, T.; Cebrian Mico, MC.; Córdoba-Sellés, MDC.; Jordá, C.; Font San Ambrosio, MI. (2016). Turnip yellow mosaic virus in Chinese cabbage in Spain: Commercial seed transmission and molecular characterization. EUROPEAN JOURNAL OF PLANT PATHOLOGY. 146(2):433-442. doi:10.1007/s10658-016-0929-3S4334421462Assis Filho, M., & Sherwood, J. L. (2000). Evaluation of seed transmission of Turnip yellow mosaic virus and Tobacco mosaic virus in Arabidopsis thaliana. Phytopathology, 90, 1233–1238.Benetti, M. P., & Kaswalder, F. (1983). Trasmisione per seme del virus del mosaico giallo rapa. Annali dell Istituto Sperimentale per la Patologia Vegetale, 8, 67–70.Blok, J., Mackenzie, A., Guy, P., & Gibbs, A. (1987). Nucleotide sequence comparisons of Turnip yellow mosaic virus isolates from Australia and Europe. Archives of Virology, 97, 283–295.Brunt, A., Crabtree, K., Dallwitz, M., Gibbs, A., Watson, L., & Zurcher, E.J. (1996). Plant Viruses Online: Descriptions and Lists from the VIDE Database. Version: 20th August 1996. URL http://biology.anu.edu.au/Groups/MES/vide/ .Campbell, R. N., Wipf-Scheibel, C., & Lecoq, H. (1996). Vector-assissted seed transmission of melon necrotic spot virus in melon. Phytopathology, 86, 1294–1298.Dreher, T. W., & Bransom, K. L. (1992). Genomic RNA sequence of Turnip yellow mosaic virus isolate TYMC, a cDNA-based clone with verified infectivity. Plant Molecular Biology, 18, 403–406.Fakhro, A., Von Bargen, S., Bandte, M., Büttner, C., Franken, P., & Schwarz, D. (2011). Susceptibility of different plant species and tomato cultivars to two isolates of Pepino mosaic virus. European Journal of Plant Pathology, 129, 579–590.Gibbs, A. J., & Gower, J. C. (1960). The use of a multiple-transfer method in plant virus transmission studies: some statistical points arising in the analysis of results. Annals of Applied Biology, 48, 75–83.Hayden, C. M., Mackenzie, A. M., & Gibbs, A. J. (1998a). Virion protein sequence variation among Australian isolates of turnip yellow mosaic tymovirus. Archives of Virology, 143, 191–201.Hayden, C. M., Mackenzie, A. M., Skotnicki, M. L., & Gibbs, A. (1998b). Turnip yellow mosaic virus isolates with experimentally produced recombinant virion proteins. Journal of General Virology, 79, 395–403.Hein, A. (1984). Transmission of Turnip yellow mosaic virus through seed of Camelina sativa gold of pleasure. Journal of Plant Diseases and Protection, 91, 549–551.Herrera-Vásquez, J. A., Córdoba-Sellés, M. C., Cebrián, M. C., Alfaro-Fernández, A., & Jordá, C. (2009). Seed transmission of Melon necrotic spot virus and efficacy of seed-disinfection treatments. Plant Pathology, 58, 436–452.Hull, R. (2002). Matthews’ plant virology (4a ed.1001 pp). San Diego: Academic Press.Johansen, E., Edwards, M. C., & Hampton, R. O. (1994). Seed transmission of viruses: current perspectives. Annual Review of Phytopathology, 32, 363–386.Kirino, N., Inoue, K., Tanina, K., Yamazaki, Y., & Ohki, S. T. (2008). Turnip yellow mosaic virus isolated from Chinese cabbage in Japan. Journal of General Plant Pathology, 74, 331–334.Markham, R., & Smith, K. S. (1949). Studies on the virus of turnip yellow mosaic. Parasitology, 39, 330–342.Mathews, R. E. F. (1980). Turnip yellow mosaic virus, CMI/AAB Descriptions of plant virus No. 230 (No. 2 revised). Kew: Commonwealth Mycology Institute/Association of Applied Biologists.Mitchell, E. J., & Bond, J. M. (2005). Variation in the coat protein sequence of British isolates of Turnip yellow mosaic virus and comparison with previously published isolates. Archives of Virology, 150, 2347–2355.Pagán, I., Fraile, A., Fernández-Fueyo, E., Montes, N., Alonso-Blanco, C., & García-Arenal, F. (2010). Arabidopsis thaliana as a model for the study of plant-virus co-evolution. Philosophical Transations of the Royal Society Biological Sciences, 365, 1983–1995.Paul, H. L., Gibbs, A., & Wittman-Liebold, B. (1980). The relationships of certain Tymoviruses assessed from the amino acid composition of their coat proteins. Intervirology, 13, 99–109.Pelikanova, J. (1990). Garlic mustard a spontaneous host of TYMV. Ochrana Rostlin, 26, 17–22.Procházková, Z. (1980). Host range and symptom differences between isolates of Turnip mosaic virus obtained from Sisymbrium loeselii. Biologia Plantarum, 22, 341–347.Rimmer, S. R., Shtattuck, V. I., & Buchwaldt, L. (2007). Compendium of brassica diseases (1ª Edición ed.p. 117). USA: APS press.Rot, M. E., & Jelkman, W. (2001). Characterization and detection of several filamentous viruses of cherry: Adaptation of an alternative cloning method (DOP-PCR), and modification of an RNA extraction protocol. European Journal of Plant Pathology, 107, 411–420.Sabanadzovic, S., Abou-Ghanem, N., Castellano, M. A., Digiaero, M., & Martelli, G. P. (2000). Grapevine fleck virus-like in Vitis. Archives of Virology, 145, 553–565.Špack, J., & Kubelková, D. (2000). Serological variability among European isolates of Radish mosaic virus. Plant Pathology, 49, 295–301.Špack, J., Kubelková, D., & Hnilicka, E. (1993). Seed transmission of Turnip yellow mosaic virus in winter turnip and winter oilseed rapes. Annals of Applied Biology, 123, 33–35.Stobbs, L. W., Cerkauskas, R. F., Lowery, T., & VanDriel, L. (1998). Occurrence of Turnip yellow mosaic virus on oriental cruciferours vegetables in Southern Ontario, Canada. Plant Disease, 82, 351.Tamura, K., Peterson, D., Peterson, N., Stecher, G., Nei, M., & Kumar, S. (2011). MEGA5: molecular evolutionary genetics analysis using maximum likelihood, evolutionary distance, and maximum parsimony methods. Molecular Biology and Evolution, 28, 2731–2739