Single-gene speciation with pleiotropy: effects of allele dominance population size and delayed inheritance

Single-gene speciation is considered to be unlikely, but an excellent example is found in land snails, in which a gene for left-right reversal has given rise to new species multiple times. This reversal might be facilitated by their small population sizes and maternal effect (i.e., "delayed inheritance", in which an individual.s phenotype is determined by the genotype of its mother). Recent evidence suggests that a pleiotropic effect of the speciation gene on anti-predator survival may also promote speciation. Here we theoretically demonstrate that, without a pleiotropic effect, in small populations the fixation probability of a recessive mutant is higher than a dominant mutant, but they are identical for large populations and sufficiently weak selection. With a pleiotropic effect that increases mutant viability, a dominant mutant has a higher fixation probability if the strength of viability selection is sufficiently greater than that of reproductive isolation, whereas a recessive mutant has a higher fixation probability otherwise. Delayed inheritance increases the fixation probability of a mutant if viability selection is weaker than reproductive isolation. Our results clarify the conflicting effects of viability selection and positive frequency-dependent selection due to reproductive isolation and provide a new perspective to single-gene speciation theory

Single-gene speciation: mating and gene flow between mirror-image snails

Variation in the shell coiling, or chirality, of land snails provides an opportunity to investigate the potential for “single-gene” speciation, because mating between individuals of opposite chirality is believed not possible if the snails mate in a face-to-face position. However, the evidence in support of single-gene speciation is sparse, mostly based upon single-gene mitochondrial studies and patterns of chiral variation between species. Previously, we used a theoretical model to show that as the chiral phenotype of offspring is determined by the maternal genotype, occasional chiral reversals may take place and enable gene flow between mirror image morphs, preventing speciation. Here, we show empirically that there is recent or ongoing gene flow between the different chiral types of Japanese Euhadra species. We also report evidence of mating between mirror-image morphs, directly showing the potential for gene flow. Thus, theoretical models are suggestive of gene flow between oppositely coiled snails, and our empirical study shows that they can mate and that there is gene flow in Euhadra. More than a single gene is required before chiral variation in shell coiling can be considered to have created a new species

The astrometric Gaia-FUN-SSO observation campaign of 99 942 Apophis

Astrometric observations performed by the Gaia Follow-Up Network for Solar System Objects (Gaia-FUN-SSO) play a key role in ensuring that moving objects first detected by ESA's Gaia mission remain recoverable after their discovery. An observation campaign on the potentially hazardous asteroid (99 942) Apophis was conducted during the asteroid's latest period of visibility, from 12/21/2012 to 5/2/2013, to test the coordination and evaluate the overall performance of the Gaia-FUN-SSO . The 2732 high quality astrometric observations acquired during the Gaia-FUN-SSO campaign were reduced with the Platform for Reduction of Astronomical Images Automatically (PRAIA), using the USNO CCD Astrograph Catalogue 4 (UCAC4) as a reference. The astrometric reduction process and the precision of the newly obtained measurements are discussed. We compare the residuals of astrometric observations that we obtained using this reduction process to data sets that were individually reduced by observers and accepted by the Minor Planet Center. We obtained 2103 previously unpublished astrometric positions and provide these to the scientific community. Using these data we show that our reduction of this astrometric campaign with a reliable stellar catalog substantially improves the quality of the astrometric results. We present evidence that the new data will help to reduce the orbit uncertainty of Apophis during its close approach in 2029. We show that uncertainties due to geolocations of observing stations, as well as rounding of astrometric data can introduce an unnecessary degradation in the quality of the resulting astrometric positions. Finally, we discuss the impact of our campaign reduction on the recovery process of newly discovered asteroids.Comment: Accepted for publication in A&

The astrometric Gaia-FUN-SSO observation campaign of 99942 Apophis

© 2015 ESO. Aims. Astrometric observations performed by the Gaia Follow-Up Network for Solar System Objects (Gaia-FUN-SSO) play a key role in ensuring that moving objects first detected by ESA's Gaia mission remain recoverable after their discovery. An observation campaign on the potentially hazardous asteroid (99 942) Apophis was conducted during the asteroid's latest period of visibility, from 12/21/2012 to 5/2/2013, to test the coordination and evaluate the overall performance of the Gaia-FUN-SSO. Methods. The 2732 high quality astrometric observations acquired during the Gaia-FUN-SSO campaign were reduced with the Platform for Reduction of Astronomical Images Automatically (PRAIA), using the USNO CCD Astrograph Catalogue 4 (UCAC4) as a reference. The astrometric reduction process and the precision of the newly obtained measurements are discussed. We compare the residuals of astrometric observations that we obtained using this reduction process to data sets that were individually reduced by observers and accepted by the Minor Planet Center. Results. We obtained 2103 previously unpublished astrometric positions and provide these to the scientific community. Using these data we show that our reduction of this astrometric campaign with a reliable stellar catalog substantially improves the quality of the astrometric results. We present evidence that the new data will help to reduce the orbit uncertainty of Apophis during its close approach in 2029. We show that uncertainties due to geolocations of observing stations, as well as rounding of astrometric data can introduce an unnecessary degradation in the quality of the resulting astrometric positions. Finally, we discuss the impact of our campaign reduction on the recovery process of newly discovered asteroids

A novel Tn antigen epitope‑recognizing antibody for MUC1 predicts clinical outcome in patients with primary lung adenocarcinoma

Mucin 1 (MUC1) expression is upregulated in multiple types of cancer, including lung cancer. However, the conventional anti‑MUC1 antibody is not useful for the differentiation of malignant lung tumors and benign lesions due to its limited specificity. Our previous study screened a novel epitope‑defined antibody against cancer‑associated sugar chain structures that specifically recognizes the MUC1 Tn antigen (MUC1‑Tn ED Ab). In the present study, its potential utility as a diagnostic marker and therapeutic tool for lung adenocarcinoma (ADC) was examined. Immunohistochemical analysis of a lung ADC tissue microarray was performed using the MUC1‑Tn ED Ab (clone SN‑102), and the results were compared with those of another clone and commercially available MUC1 antibodies. The association between positive immunoreactivity of SN‑102 and clinicopathologic factors was analyzed. Furthermore, the association between MUC1‑Tn expression and epithelial‑mesenchymal transition markers and radiological characteristics was analyzed. Moderate or high MUC1‑Tn expression (MUC1‑Tn‑H) was observed in 138 (78.9%) of the 175 lung ADC cases. MUC1‑Tn‑H was associated with male sex, cigarette smoking, tumor extension, pleural invasion, and higher preoperative serum carcinoembryonic antigen and cytokeratin 19 fragment levels. Tumors with MUC1‑Tn‑H had higher consolidation/tumor ratios according to computed tomography and greater uptakes of 18F‑fluorodeoxyglucose. A total of 46 (26.9%) of the tumors had mesenchymal features, and MUC1‑Tn positivity was higher in the mesenchymal group than in the epithelial and intermediate groups (P<0.01 and P<0.01, respectively). Patients with tumors exhibiting MUC1‑Tn‑H had significantly shorter 5‑year overall and disease‑free survival times (P=0.011 and P<0.001, respectively). Additionally, MUC1‑Tn‑H was identified as an independent prognostic factor in multivariate analysis (P=0.024). MUC1‑Tn is specific for lung cancer cells and can improve diagnostic capabilities. Additionally, it may be a potential therapeutic target in lung ADC

Laparoscopic and endoscopic cooperative surgery as palliative treatment for elderly patients with gastric cancer

Oncological gastrectomy, despite remaining a mainstay of gastric cancer treatment, is reportedly associated with high morbidity and mortality in elderly patients. Less invasive modalities suitable for senior gastric cancer patients with insufficient surgical tolerance are thus needed. We adopted laparoscopic and endoscopic cooperative surgery as an alternative for elderly gastric cancer cases unsuitable for aggressive gastrectomy. To date, we have experienced three cases (80–86 years old) undergoing palliative laparoscopic and endoscopic cooperative surgery. Postoperative courses were uneventful in two cases, while sutural leakage occurred in the other, which was managed conservatively. Postoperative loss of body weight and skeletal muscle mass appeared to be minimal according to bioelectrical impedance analyses. No gastric cancer recurrence was detected in any of our three cases. As to the balance between radicality and safety, laparoscopic and endoscopic cooperative surgery is potentially a viable option for geriatric gastric cancer patients in whom conventional gastrectomy is contraindicated