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Abstract The genomes of many plants, animals, and fungi frequently comprise dispensable B chromosomes that rely upon various chromosomal drive mechanisms to counteract the tendency of non-essential genetic elements to be purged over time. The B chromosome of rye – a model system for nearly a century – undergoes targeted nondisjunction during first pollen mitosis, favouring segregation into the generative nucleus, thus increasing their numbers over generations. However, the genetic mechanisms underlying this process are poorly understood. Here, using a newly-assembled, ~430 Mb-long rye B chromosome pseudomolecule, we identify five candidate genes whose role as trans-acting moderators of the chromosomal drive is supported by karyotyping, chromosome drive analysis and comparative RNA-seq. Among them, we identify DCR28, coding a microtubule-associated protein related to cell division, and detect this gene also in the B chromosome of Aegilops speltoides. The DCR28 gene family is neo-functionalised and serially-duplicated with 15 B chromosome-located copies that are uniquely highly expressed in the first pollen mitosis of rye.

Background: Perianal rhabdomyosarcoma ((P)RMS) are rare and have a poor prognosis. Data in young children are limited and local therapy is not well defined. Combined brachytherapy and surgery is routinely being used for RMS at other sites in children as it provides good oncologic outcomes and allows for organ-sparing surgery. The objective of this study was to evaluate this combination treatment for local tumor control and organ-sparing surgery in young children with (P)RMS. Methods: A retrospective review of the medical records of all children who underwent surgery and brachytherapy for (P)RMS at our institution since 2009 was conducted. Results: Surgery for (P)RMS was performed in 6 patients at a median age of 19 months (range 8–50). Embryonal RMS was diagnosed in 4 patients and alveolar RMS in 2 patients, of which 1 patient had FOXO1 fusion-positive RMS. All patients underwent postoperative high-dose rate (HDR) brachytherapy. Organ-preserving surgery was achieved in 5 of 6 patients (83 %). In 1 patient, the entire sphincter was infiltrated, making organ-preserving resection impossible. 5 of 6 patients (83 %) exhibited an event-free and overall survival at a median follow-up of 26 months (range 8–107). One patient died due to locoregional recurrence. Complications were urethral leakage in 1 patient followed by urethral stenosis and delayed wound healing and vaginal stenosis in another patient. No patient reported fecal incontinence. Conclusions: Combined treatment with surgery and HDR brachytherapy is feasible in very young children with (P)RMS and leads to a favorable oncologic outcome. Preliminary data show a good functional preservation.

Abstract The presence of incompatibility alleles in primary amphidiploids constitutes a reproductive barrier in newly synthesized wheat-rye hybrids. To overcome this barrier, the genome stabilization process includes large-scale chromosome rearrangements. In incompatible crosses resulting in fertile amphidiploids, the elimination of one of the incompatible alleles Eml-A1 or Eml-R1b can occur already in the somatic tissue of the wheat × rye hybrid embryo. We observed that the interaction of incompatible loci Eml-A1 of wheat and Eml-R1b of rye after overcoming embryo lethality leads to hybrid sterility in primary triticale. During subsequent seed reproductions (R1, R2 or R3) most of the chromosomes of A, B, D and R subgenomes undergo rearrangement or eliminations to increase the fertility of the amphidiploid by natural selection. Genotyping-by-sequencing (GBS) coverage analysis showed that improved fertility is associated with the elimination of entire and partial chromosomes carrying factors that either cause the disruption of plant development in hybrid plants or lead to the restoration of the euploid number of chromosomes (2n = 56) in the absence of one of the incompatible alleles. Highly fertile offspring obtained in compatible and incompatible crosses can be successfully adapted for the production of triticale pre-breeding stocks.

Introduction: Pancreaticopleural fistula (PPF) is a very rare complication of pancreatitis. The symptoms are non-specific and the diagnosis is often missed. Case presentation: A 14-year-old adolescent was admitted to the department of pediatric surgery with several readmissions due to recurrent left pleural effusion and chest pain. The patient also had a history of a left-sided congenital diaphragmatic hernia (CDH), which was surgically corrected via laparotomy at the age of two. The pleural effusion was explained in the context of pneumonia, but elevated serum levels of amylase and lipase prompted imaging. Computer tomography (CT) and standard magnetic resonance imaging (MRI) showed a small gap in the diaphragm and the pancreatic tail nearby leading to the diagnosis of recurrent CDH. Explorative thoracoscopy was performed, but showed the diaphragm intact. Pleurodesis was realized to treat the effusion. Two months later, recurrence of the pleural effusion in the left hemithorax and pancreatitis occurred. Magnetic resonance cholangiopancreatography (MRCP) showed a small subphrenic cyst close to the pancreatic tail and multiple supradiaphragmal cysts for the first time. Persistently, the small gap in the diaphragm close to the pancreatic tail was detected and the now suspected diagnosis was PPF. Subsequently, laparoscopic resection of the pancreatic tail was performed including the closure of the diaphragmatic gap. The course was uneventful, the pleural effusion disappeared, and the levels of serum pancreatic enzymes normalized during follow-up. Conclusion: PPF is rare and various entities may masquerade the diagnosis. A massive pleural effusion in combination with pancreatitis may indicate this serious condition.