Ancestral population reconstitution from isofemale lines as a tool for experimental evolution

Experimental evolution is a powerful tool to study adaptation under controlled conditions. Laboratory natural selection experiments mimic adaptation in the wild with better-adapted genotypes having more offspring. Because the selected traits are frequently not known, adaptation is typically measured as fitness increase by comparing evolved populations against an unselected reference population maintained in a laboratory environment. With adaptation to the laboratory conditions and genetic drift, however, it is not clear to what extent such comparisons provide unbiased estimates of adaptation. Alternatively, ancestral variation could be preserved in isofemale lines that can be combined to reconstitute the ancestral population. Here, we assess the impact of selection on alleles segregating in newly established Drosophila isofemale lines. We reconstituted two populations from isofemale lines and compared them to two original ancestral populations (AP) founded from the same lines shortly after collection. No significant allele frequency changes could be detected between both AP and simulations showed that drift had a low impact compared to Pool-Seq-associated sampling effects. We conclude that laboratory selection on segregating variation in isofemale lines is too weak to have detectable effects, which validates ancestral population reconstitution from isofemale lines as an unbiased approach for measuring adaptation in evolved populations.Pierre Nouhaud, Ray Tobler, Viola Nolte, Christian Schlöttere

Ancestral population reconstitution from isofemale lines as a tool for experimental evolution

Experimental evolution is a powerful tool to study adaptation under controlled conditions. Laboratory natural selection experiments mimic adaptation in the wild with better-adapted genotypes having more offspring. Because the selected traits are frequently not known, adaptation is typically measured as fitness increase by comparing evolved populations against an unselected reference population maintained in a laboratory environment. With adaptation to the laboratory conditions and genetic drift, however, it is not clear to what extent such comparisons provide unbiased estimates of adaptation. Alternatively, ancestral variation could be preserved in isofemale lines that can be combined to reconstitute the ancestral population. Here, we assess the impact of selection on alleles segregating in newly established Drosophila isofemale lines. We reconstituted two populations from isofemale lines and compared them to two original ancestral populations (AP) founded from the same lines shortly after collection. No significant allele frequency changes could be detected between both AP and simulations showed that drift had a low impact compared to Pool-Seq-associated sampling effects. We conclude that laboratory selection on segregating variation in isofemale lines is too weak to have detectable effects, which validates ancestral population reconstitution from isofemale lines as an unbiased approach for measuring adaptation in evolved populations.Pierre Nouhaud, Ray Tobler, Viola Nolte, Christian Schlöttere

Instability of natural selection at candidate barrier loci underlying speciation in wood ants

doi: 10.1111/mec.15606Speciation underlies the generation of novel biodiversity. Yet, there is much to learn about how natural selection shapes genomes during speciation. Selection is assumed to act against gene flow at barrier loci, promoting reproductive isolation. However, evidence for gene flow and selection is often indirect and we know very little about the temporal stability of barrier loci. Here we utilize haplodiploidy to identify candidate male barrier loci in hybrids between two wood ant species. As ant males are haploid, they are expected to reveal recessive barrier loci, which can be masked in diploid females if heterozygous. We then test for barrier stability in a sample collected 10 years later and use survival analysis to provide a direct measure of natural selection acting on candidate male barrier loci. We find multiple candidate male barrier loci scattered throughout the genome. Surprisingly, a proportion of them are not stable after 10 years, natural selection apparently switching from acting against to favouring introgression in the later sample. Instability of the barrier effect and natural selection for introgressed alleles could be due to environment-dependent selection, emphasizing the need to consider temporal variation in the strength of natural selection and the stability of the barrier effect at putative barrier loci in future speciation work.Peer reviewe

Comparison of open and robotic-assisted partial nephrectomy approaches using multicentric data (UroCCR-47 study)

We compared the outcomes of robotic-assisted partial nephrectomy (RPN) and open partial nephrectomy (OPN) using contemporary data to respond to unmet clinical needs. Data from patients included in the registry who underwent partial nephrectomy between January 01, 2014 and June 30, 2017 within 20 centres of the French Network for Research on Kidney Cancer UroCCR were collected (NCT03293563). Statistical methods included adjusted multivariable analyses. Rates of peri- and post-operative transfusion, and of surgical revision, were lower in the RPN (n = 1434) than the OPN (n = 571) group (2.9% vs. 6.0%, p = 0.0012; 3.8% vs. 11.5%, p < 0.0001; 2.4% vs. 6.7%, p < 0.0001, respectively). In multivariable analyses, RPN was independently associated with fewer early post-operative complications than OPN (overall: odds-ratio [95% confidence interval, CI] = 0.48 [0.35–0.66]; severe: 0.29 [0.16–0.54], p < 0.0001 for both) and shorter hospital stays (34% [30%; 37%], p < 0.0001). RPN was also a significantly associated with a decresedrisk of post-operative acute renal failure, and new-onset chronic kidney disease at 3 and 12 months post-surgery. There were no between-group differences in oncological outcomes. In comparison with OPN, RPN was associated with improved peri- and post-operative morbidity, better functional outcomes, and shorter hospital stays. Our results support the use of RPN, even for large and complex tumours

No selection for change in polyandry under experimental evolution

What drives mating system variation is a major question in evolutionary biology. Female multiple mating (polyandry) has diverse evolutionary consequences, and there are many potential benefits and costs of polyandry. However, our understanding of its evolution is biased towards studies enforcing monandry in polyandrous species. What drives and maintains variation in polyandry between individuals, genotypes, populations and species remains poorly understood. Genetic variation in polyandry may be actively maintained by selection, or arise by chance if polyandry is selectively neutral. In Drosophila pseudoobscura, there is genetic variation in polyandry between and within populations. We used isofemale lines to found replicate populations with high or low initial levels of polyandry and tracked polyandry under experimental evolution over seven generations. Polyandry remained relatively stable, reflecting the starting frequencies of the experimental populations. There were no clear fitness differences between high versus low polyandry genotypes, and there was no signature of balancing selection. We confirmed these patterns in direct comparisons between evolved and ancestral females and found no consequences of polyandry for female fecundity. The absence of differential selection even when initiating populations with major differences in polyandry casts some doubt on the importance of polyandry for female fitness

Genome of Diuraphis noxia, a global aphid pest of small grains

Background: The Russian wheat aphid, Diuraphis noxia Kurdjumov, is one of the most important pests of small grains throughout the temperate regions of the world. This phytotoxic aphid causes severe systemic damage symptoms in wheat, barley, and other small grains as a direct result of the salivary proteins it injects into the plant while feeding.Results: We sequenced and de novo assembled the genome of D. noxia Biotype 2, the strain most virulent to resistance genes in wheat. The assembled genomic scaffolds span 393 MB, equivalent to 93% of its 421 MB genome, and contains 19,097 genes. D. noxia has the most AT-rich insect genome sequenced to date (70.9%), with a bimodal CpG(O/E) distribution and a complete set of methylation related genes. The D. noxia genome displays a widespread, extensive reduction in the number of genes per ortholog group, including defensive, detoxification, chemosensory, and sugar transporter groups in comparison to the Acyrthosiphon pisum genome, including a 65% reduction in chemoreceptor genes. Thirty of 34 known D. noxia salivary genes were found in this assembly. These genes exhibited less homology with those salivary genes commonly expressed in insect saliva, such as glucose dehydrogenase and trehalase, yet greater conservation among genes that are expressed in D. noxia saliva but not detected in the saliva of other insects. Genes involved in insecticide activity and endosymbiont-derived genes were also found, as well as genes involved in virus transmission, although D. noxia is not a viral vector.Conclusions: This genome is the second sequenced aphid genome, and the first of a phytotoxic insect. D. noxia's reduced gene content of may reflect the influence of phytotoxic feeding in shaping the D. noxia genome, and in turn in broadening its host range. The presence of methylation-related genes, including cytosine methylation, is consistent with other parthenogenetic and polyphenic insects. The D. noxia genome will provide an important contrast to the A. pisum genome and advance functional and comparative genomics of insects and other organisms.Peer reviewedBiochemistry and Molecular Biolog

Sequential treatment with ProACT™ device implantation after male sling failure for male urinary incontinence

International audienceThere is no strong evidence for second line therapy after male sling failure for post-prostatectomy urinary incontinence (PPUI). We report the outcomes after periurethral balloons implantation for persistence or recurrence of mild PPI symptoms after male sling implantation.L’inefficacité d’une bandelette sous-urétrale TOMS dans le traitement de l’incontinence urinaire légère à modérée amène à rechercher des alternatives thérapeutiques de seconde intention. Il existe très peu de données sur la pose de ballons ACT après bandelette sous-urétrale

Semipermeable species boundaries create opportunities for gene flow and adaptive potential

International audienceHybridisation and gene flow can have both deleterious and adaptive consequences for natural populations and species. To better understand the extent of hybridisation in nature and the balance between its beneficial and deleterious outcomes in a changing environment, information on naturally hybridising nonmodel organisms is needed. This requires the characterisation of the structure and extent of natural hybrid zones. Here, we study natural populations of five keystone mound-building wood ant species in the Formica rufa group across Finland. No genomic studies across the species group exist, and the extent of hybridisation and genomic differentiation in sympatry is unknown. Combining genome-wide and morphological data, we demonstrate more extensive hybridisation than was previously detected between all five species in Finland. Specifically, we reveal a mosaic hybrid zone between Formica aquilonia, F. rufa and F. polyctena, comprising further generation hybrid populations. Despite this, we find that F. rufa, F. aquilonia, F. lugubris and F. pratensis form distinct gene pools in Finland. We also find that hybrids occupy warmer microhabitats than the nonadmixed populations of cold-adapted F. aquilonia, and suggest that warm winters and springs, in particular, may benefit hybrids over F. aquilonia, the most abundant F. rufa group species in Finland. In summary, our results indicate that extensive hybridisation may create adaptive potential that could promote wood ant persistence in a changing climate. Additionally, they highlight the potentially significant ecological and evolutionary consequences of extensive mosaic hybrid zones, within which independent hybrid populations face an array of ecological and intrinsic selection pressures

Apprentissage de l’HoLEP : vers une formation standardisée et une stratégie d’équipe

International audienc

Long-term outcomes of I-Stop TOMS™ male sling implantation for post-prostatectomy incontinence management

International audienceOBJECTIVES:To report long-term outcomes after I-Stop TOMS™ implantation for PPI.PATIENTS AND METHODS:A retrospective evaluation was conducted in three tertiary reference centers. All consecutive patients implanted with an I-Stop TOMS™ sling between 2007 and 2012 for mild to moderate PPI (24-hour Pad test<400g) without history of pelvic radiation therapy were included. Evaluation had been conducted preoperatively, at one and six months postoperative and yearly thereafter. The main outcome criterion was the number of pads per day. Secondary criteria were International Consultation on Incontinence Questionnaire (ICIQ), SF-36 questionnaire, and complications.RESULTS:A hundred patients were evaluated with a median follow-up of 58months [19-78]. Pad use was significantly reduced and quality of life improved at last follow-up (P<0.0001). The percentage of patients dry and socially continent (0 or 1 pad) were 40% and 77% at 1 year, then dropped to 15% and 22%, respectively after 5years. Twelve patients were treated by artificial urinary sphincter implantation, five by ProACT™ balloons and one by a re-do I-Stop TOMS™. No severe complications were recorded at last follow-up.CONCLUSIONS:I-Stop TOMS™ implantation is a safe and effective option in the short-term for mild to moderate PPI management. However, a significant trend to recurrence of leakage has been established after long-term follow-up. If confirmed by further studies, these results may substantially impact patient information before male sling implantation