Selection Events Research Articles

Analysis of the Origin of Double Mosaic Aneuploidy in Two Cases

We present 2 cases of double mosaic aneuploidy harboring 2 or more different aneuploid cell lines, but no line with a normal chromosome constitution. One of these cases presented mosaicism of sex chromosome aneuploid cell lines (47,XXX/45,X) along with another line containing an autosomal trisomy (47,XX,+8), while the other case showed mosaicism of 2 different autosomal trisomy cell lines (47,XY,+5 and 47,XY,+8). To elucidate the mechanisms underlying these mosaicisms, we conducted molecular cytogenetic analyses. Genotyping data from the SNP microarray indicated that 2 sequential meiotic or early postzygotic segregation errors likely had occurred followed by natural selection. These cases suggest that frequent segregation errors and selection events in the meiotic and early postzygotic stages lead to this condition.

MHC Restriction: Where Are We Now?

MHC Restriction: Where Are We Now?

Elevation-related differences in annual survival of adult food-caching mountain chickadees are consistent with natural selection on spatial cognition

Animals inhabiting montane gradients experience varying winter climates that may result in differential selection on survival-related traits. Higher elevations in temperate climates are characterized by harsher winters with greater and longer-lasting snow cover compared to lower elevations, potentially leading to stronger selection for traits that improve fitness under these harsher conditions. For food-caching mountain chickadees, Poecile gambeli, inhabiting harsh high elevation environments, individual variation in spatial cognitive abilities related to cache retrieval is associated with significant differences in overwinter survival. Compared to lower elevations, stronger predicted selection on traits needed for overwinter survival at higher elevations can be expected to result in higher adult annual survival despite harsher environmental conditions, indicating that individuals that survive their first winter are better suited to survive similar subsequent selection events. Here, we used a Bayesian hierarchical Cormack-Jolly-Seber (CJS) model to estimate and compare survival of adult mountain chickadees at higher and lower elevations over 3 years. We showed that adult survival was consistently higher at higher elevations despite much harsher environmental conditions, supporting our hypothesis that selection on overwinter survival-related traits (such as spatial cognition) is stronger at our high elevation study area than at lower elevations. Understanding how environmental conditions are associated with different selection strengths on survival-related traits is an important question in behavioral ecology. Directly estimating differences in strength of selection is daunting, but comparing survival between environments may provide an alternative method. We tested for differences in adult survival in a resident food-caching species at higher and lower elevations varying in winter climate severity. These birds rely on food caches for winter survival, and juvenile birds with better spatial cognition (needed for cache retrieval) have higher survival during their first year at higher harsher elevations. Here, we report higher adult survival at higher elevations compared to lower elevations, despite much harsher winter environment. Such findings support our hypothesis for stronger selection in harsher winter conditions because individuals that survive their first year under stronger selection are better suited to survive subsequent selection events.

Expectations affect physical causation judgments.

When several causes contributed to an outcome, people often single out one as "the" cause. What explains this selection? Previous work has argued that people select abnormal events as causes, though recent work has shown that sometimes normal events are preferred over abnormal ones. Existing studies have relied on vignettes that commonly feature agents committing immoral acts. An important challenge to the thesis that norms permeate causal reasoning is that people's responses may merely reflect pragmatic or social reasoning rather than arising from causal cognition per se. We tested this hypothesis by asking whether the previously observed patterns of causal selection emerge in tasks that recruit participants' causal reasoning about physical systems. Strikingly, we found that the same patterns observed in vignette studies with intentional agents arise in visual animations of physical interactions. Our results demonstrate how deeply normative expectations affect causal cognition. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

DNA barcoding, phylogeny and phylogeography of the cyst nematode species from the genus Globodera (Tylenchida: Heteroderidae)

Summary Globodera presently contains 13 valid and three as yet undescribed species. Three species, G. rostochiensis, G. pallida and G. ellingtonae, the potato cyst nematodes (PCN), cause significant economic losses on potatoes around the world. In our study we provide comprehensive phylogenetic analyses of 455 ITS rRNA, 219 COI and 164 cytb gene sequences of 11 valid and two undescribed species of Globodera using Bayesian inference, maximum likelihood and statistical parsimony. New 205 COI, 116 cytb and 21 ITS rRNA gene sequences were obtained from 148 populations of these species collected from 23 countries. The phylogenetic analysis revealed that Globodera displayed two main clades in the trees: i) Globodera from South and North America parasitising plants from Solanaceae; and ii) Globodera from Africa, Europe, Asia and New Zealand parasitising plants from Asteraceae and other families. Based on the results of phylogeographical analysis and age estimation of clades with a molecular clock approach, it is hypothesised that Globodera species originated and diversified from several centres of speciation located in mountain regions and then dispersed across the world from these regions during the Pleistocene. High genetic diversity of Bolivian populations of G. rostochiensis was observed for both mtDNA genes. Analysis of phylogenetic relationships of G. pallida and G. rostochiensis populations revealed incongruence in topology between networks inferred from mtDNA genes, which might be an indication of possible recombination and selective introgression events through gene flow between previously isolated populations. This puts some limitations on the use of the mtDNA marker as universal DNA barcoding identifier for PCN. Globodera bravoae syn. n. is proposed as a junior synonym of G. mexicana.

Molecular mapping and identification of quantitative trait loci for domestication traits in the field cress (Lepidium campestre L.) genome

Lepidium campestre (L.) or field cress is a multifaceted oilseed plant, which is not yet domesticated. Moreover, the molecular and genetic mechanisms underlying the domestication traits of field cress remain largely elusive. The overarching goal of this study is to identify quantitative trait loci (QTL) that are fundamental for domestication of field cress. Mapping and dissecting quantitative trait variation may provide important insights into genomic trajectories underlying field cress domestication. We used 7624 single nucleotide polymorphism (SNP) markers for QTL mapping in 428 F2 interspecific hybrid individuals, while field phenotyping was conducted in F2:3 segregating families. We applied multiple QTL mapping algorithms to detect and estimate the QTL effects for seven important domestication traits of field cress. Verification of pod shattering across sites revealed that the non-shattering lines declined drastically whereas the shattering lines increased sharply, possibly due to inbreeding followed by selection events. In total, 1461 of the 7624 SNP loci were mapped to eight linkage groups (LGs), spanning 571.9 cM map length. We identified 27 QTL across all LGs of field cress genome, which captured medium to high heritability, implying that genomics-assisted selection could deliver domesticated lines in field cress breeding. The use of high throughput genotyping can accelerate the process of domestication in novel crop species. This is the first QTL mapping analysis in the field cress genome that may lay a foundational framework for positional or functional QTL cloning, introgression as well as genomics-assisted breeding in field cress domestication.

Exploring the resistome, virulome and microbiome of drinking water in environmental and clinical settings

Aquatic ecosystems harbor a vast pool of antibiotic resistance genes (ARGs), which can suffer mutation, recombination and selection events. Here, we explored the diversity of ARGs, virulence factors and the bacterial community composition in water samples before (surface raw water, RW) and after (disinfected water, DW) drinking water conventional treatment, as well as in tap water (TW) and ultrafiltration membranes (UM, recovered from hemodialysis equipment) through metagenomics. A total of 852 different ARGs were identified, 21.8% of them only in RW, which might reflect the impact of human activities on the river at the sampling point. Although a similar resistance profile has been observed between the samples, significant differences in the frequency of clinically relevant antibiotic classes (penam and peptide) were identified. Resistance determinants to last resort antibiotics, including sequences related to mcr, optrA and poxtA and clinically relevant beta-lactamase genes (i.e. blaKPC, blaGES, blaIMP, blaVIM, blaSPM and blaNDM) were detected. 830 coding sequences (CDSs - related to 217 different ARGs) were embedded in contigs associated with mobile genetic elements, specially plasmids, of which 68% in RW, DW and TW, suggesting the importance of water environments in resistance dissemination. Shifts in bacterial pathogens genera were observed, such as a significant increase in Mycobacterium after treatment and distribution. In UM, the potentially pathogenic genus Halomonas predominated. Its draft genome was closely related to H. stevensii, hosting mainly multidrug efflux pumps. These results broaden our understanding of the global ARGs diversity and stress the importance of tracking the ever-expanding environmental resistome.

Anti-PD1-Induced Immune-Related Adverse Events and Survival Outcomes in Advanced Melanoma.

Objective response rates (ORR) appear to be higher in melanoma patients who develop immune-related adverse events (irAEs), but whether there is a similar association between irAEs and survival remains unknown. Patients with advanced melanoma treated with single-agent pembrolizumab or nivolumab in the province of Alberta from June 2014 to May 2017 were identified through the provincial pharmacy database. Chart review identified and categorized all irAEs that occurred while on anti-programmed cell death protein 1 (PD-1) checkpoint inhibitors. The primary objective was to compare overall survival (OS) with patients who developed any irAEs versus those who did not. Secondary outcomes included progression-free survival (PFS) and ORR. Among 186 patients, any-grade and grade ≥3 irAEs occurred in 88 (47%) and 27 (15%) patients, respectively; one patient died of pneumonitis. In a landmark analysis excluding patients who died within the first 12 weeks, the median follow-up was 24 months, 20 months in patients without any irAEs and 26 months in patients with irAEs (p = .006). Median OS was 39 versus 23 months (hazard ratio [HR], 0.46; p = .001) for any irAE and no irAE, respectively, and median OS not reached versus 29 months for grade ≥3 irAEs and no grade ≥3 irAEs, respectively. In multivariate analysis, elevated lactate dehydrogenase correlated with reduced OS (HR, 2.34; p = .001), whereas each additional cycle of treatment received (HR, 0.94; p < .001) and development of grade ≥3 irAEs (HR, 0.29, p = .024) were significantly associated with longer OS. Anti-PD-1-associated grade ≥3 irAEs in patients with advanced melanoma is associated with better patient outcomes, including overall survival. Previous prospective randomized clinical trials demonstrate improved response rates in patients with melanoma who develop select adverse events. The current population-based real-world study in advanced melanoma reports an association with anti-programmed cell death protein 1 (PD-1)-induced grade ≥3 immune-related adverse events (irAEs) and better patient outcomes, including overall survival. These results suggest that irAEs may be a manifestation of a patient's ability to mount a systemic immune response from PD-1-directed therapies, which may be associated with therapeutic benefit. The finding of irAEs coinciding with clinical benefit from these therapies supposes that these events are, by and large, unavoidable, and the critical management of irAEs remains essential for optimizing patient outcomes.

Real-world safety of pemetrexed, carboplatin, and pembrolizumab in U.S. NSCLC patients.

50 Background: A Phase 3 KEYNOTE-189 clinical trial showed improved clinical benefit with acceptable toxicity of pemetrexed combined with pembrolizumab and platinum (Gandhi, 2018). However, the safety data with this combination has not been evaluated in a real-world setting with large number of patients with non-squamous non-small cell lung cancer (NSQ NSCLC). Methods: Flatiron Health’s electronic health record-derived data were used to identify advanced NSQ NSCLC patients (≥18 y) who received pemetrexed, pembrolizumab, and carboplatin (≤6 cycles; Pem+Pembro+Carb) as initial treatment from May 2017 to Oct 2018. Endpoints were overall occurrence of select laboratory adverse events (AEs; any Grade and Grade ≥3), which were described by treatment phase (Pem/Pembro cycles &lt; 5 vs ≥5) and pre-specified subgroups. Results: The study included 1088 patients (median age = 68 y; male, 57%). In patients with maintenance (Pem/Pembro ≥5) cohort (N = 462), the median number of treatment cycles was 9 for Pembro and 6 for Pem. The occurrence rates of neutrophil count decrease and platelet count decrease were numerically higher in the induction phase, whereas those of chronic kidney disease (CKD) showed an opposite trend (Table). Grade ≥3 CKD occurrence rate was higher in patients with mild renal impairment (5.1% vs 2.6%) and elderly (≥75 y) patients (7.5% vs 3.3%). Conclusions: Considering the heterogeneity and vulnerability of real-world population, the laboratory AE occurrence rate with Pem+Pembro+Carb in this study was comparable with those reported in KEYNOTE-189. Various trends were observed for the respective AEs by treatment phase. [Table: see text]

GENOME-WIDE DISTRIBUTION OF AUTOZYGOSITY ISLANDS IN SLOVAK WARMBLOOD HORSE

The objective of this study was to estimate the distribution of autozygosity islands represented by homozygous segments (ROHs) in the genome of the Slovak Warmblood horse. The Slovak Warmblood is a very efficient breed with the excellent characteristics of a sport horse. The study included 37 animals that were genotyped by GGP Equine70k chip (71,947 SNPs). Only animals (36) and autosomal SNPs (62,439) with call rate &gt;90% and minor allele frequency &gt;1% were included in subsequent analyses. The homozygous segments were defined as stretches with minimum 15 consecutive homozygous SNPs of &gt;500 kb with minimum density 1 SNP per 100 kb and maximum gap between markers of 1,000 kb. The heterozygous or missing calls were not accepted. The analysis indicated in total of 8,501 autozygosity islands in the genome of the Slovak Warmblood horse. The majority of identified segments (85.42%) were most likely derived from the remote ancestors in the past. Only 0.15% of detected segments resulted from the recent selection events affecting the genetic structure of studied population. The proportion of segments varied across chromosomes. The major fraction of autosome residing in ROH was found on ECA1 (8.30%), while ECA31 showed the lowest ROH coverage. The scan for overlapping homozygous segments shared by more than 50 % of animals demonstrated that the ECA6 autosome may be under strong selection pressure. Inside those selection signals, several genes were identified including them associated with immunity and reproduction.

CheckMate 171: A phase 2 trial of nivolumab in patients with previously treated advanced squamous non-small cell lung cancer, including ECOG PS 2 and elderly populations

BackgroundCheckMate 171 (NCT02409368) is an open-label, multicentre, phase 2 trial of nivolumab in previously treated advanced squamous non-small cell lung cancer (NSCLC), conducted as part of a post-approval commitment to the European Medicines Agency (EMA). We report outcomes from this trial. MethodsPatients with Eastern Cooperative Oncology Group performance status (ECOG PS) 0–2 and disease progression during/after ≥1 systemic treatment (≥1 being platinum-based chemotherapy) for advanced or metastatic disease were treated with nivolumab 3 mg/kg every 2 weeks until progression or unacceptable toxicity. The primary end-point was incidence of grade 3–4 treatment-related select adverse events (AEs). Other end-points included overall survival (OS) and safety. ResultsOf 811 patients treated, 103 had ECOG PS 2; 278 were aged ≥70 years and 125 were ≥75 years of age. Minimum follow-up was ~18 months. Safety was similar across populations; the most frequent grade 3–4 treatment-related select AEs in all treated patients were diarrhoea (1%), increased alanine aminotransferase (ALT, 1%), pneumonitis (0.7%), colitis (0.6%) and increased aspartate aminotransferase (AST, 0.5%). Median OS was similar in all treated patients and those aged ≥70 and ≥75: 10.0 months, 10.0 months and 11.2 months, respectively. Median OS was 5.2 months in patients with ECOG PS 2. ConclusionThese results suggest that nivolumab is well tolerated and active in patients with advanced, relapsed squamous NSCLC, including the elderly, with OS outcomes consistent with phase 3 data. In patients with ECOG PS 2, nivolumab had similar tolerability, but outcomes were worse, as expected in this difficult-to-treat, poor prognosis population. Clinical trial registrationNCT02409368.

Neofunctionalization of the UCP1 mediated the non-shivering thermogenesis in the evolution of small-sized placental mammals

The acquisition of UCP1-mediated non-shivering thermogenesis (NST) was an important event during the evolution of mammals. Here, we assessed the thermogenic neofunctionalization that occurred in the mammalian UCP1, by performing detailed comparative evolutionary genomics analyses (including phylogenetic and selection analyses) of the UCP family members across all major vertebrate classes. Heterogeneously distributed positive selection signatures were found in several UCPs, being preferably located in the mitochondrial matrix domains. Additionally, comparisons with non-mammalian orthologs showed increased evolutionary rates of the mammalian UCP1, not observable in the phylogenetically related UCP2 and UCP3 paralogs. Also, parallel signatures of episodic positive selection (ω > 1) were found in the ancestral branches of both Glires (rodents and lagomorphs) and Afroinsectivores (afrosoricids and macroscelids), underlining the importance of the UCP1 thermogenic activity in these mammalian groups. Finally, we hypothesize that the independent positive selection events that occurred in these two lineages resulted in two UCP1-mediated NST approaches, namely the cold acute response in the Glires and the reproduction success enhancement in the Afroinsectivores.

A phase III study of nivolumab (Nivo) in previously treated advanced gastric or gastric esophageal junction (G/GEJ) cancer (ATTRACTION-2): Three-year update data.

383 Background: Nivo is the first immune checkpoint inhibitor (ICI) to show efficacy and tolerability in G/GEJ cancer patients refractory to or intolerant of standard chemotherapy. Although Nivo has demonstrated durable efficacy in several cancer types, no long-term efficacy data in G/GEJ cancer has been reported to date. Here, we report the 3-year survival data of Nivo in G/GEJ cancer. Methods: A total of 493 patients with unresectable advanced or recurrent G/GEJ cancer after the failure of two or more chemotherapy regimens were randomized in a 2:1 ratio to receive 3 mg/kg Nivo (N = 330) or placebo (N = 163) until disease progression or unacceptable toxicity. The primary endpoint was overall survival (OS). Updated results of the efficacy and safety were based on ≥ 3 years of follow-up after last patient enrollment. In subgroup analysis, we evaluated OS by BOR and incidence of select treatment-related adverse events (TRAEs). Results: As of data cut-off in February 2019, 3 years after last patient enrollment, the hazard ratios of OS and PFS in the Nivo group compared with the placebo group remained 0.62 and 0.60, respectively. The 36-month OS rates of Nivo and placebo were 5.6% and 1.2 % and the 36-month PFS rates were 2.4% and 0%, respectively. In the OS subgroup analysis by BOR, the median OS and 3-year OS rate in CR/PR patients with Nivo were 26.7 months and 35.5%, respectively. The incidence rate and severity of TRAEs were comparable with those of the 2-year cut-off. In the OS subgroup analysis based on the presence or absence of select TRAEs, the hazard ratio in patients with select TRAEs was 0.46 compared to those without select TRAEs. We are analyzing the baseline characteristics that are associated with long-term survival with Nivo. Conclusions: Nivo showed durable efficacy and a good safety profile on long-term follow-up in heavily pretreated G/GEJ cancer patients. Clinical trial information: NCT02267343.

On the importance of specialists for lexicase selection

Lexicase parent selection filters the population by considering one random training case at a time, eliminating any individual with an error for the current case that is worse than the best error of any individual in the selection pool, until a single individual remains. This process often stops before considering all training cases, meaning that it will ignore the error values on any cases that were not yet considered. Lexicase selection can therefore select specialist individuals that have high errors on some training cases, if they have low errors on others and those errors come near the start of the random list of cases used for the parent selection event in question. We hypothesize here that selecting such specialists, which may have high total error, plays an important role in lexicase selection’s observed performance advantages over error-aggregating parent selection methods such as tournament selection, which select specialists less frequently. We conduct experiments examining this hypothesis, and find that lexicase selection’s performance and diversity maintenance degrade when we deprive it of the ability to select specialists. We also conduct experiments with a form of tournament selection that has been modified to allow for the selection of specialists, and find that it performs better than ordinary tournament selection, but not as well as lexicase selection. These findings, and other data that we present here, help explain the improved performance of lexicase selection compared to tournament selection, and suggest that specialists help drive evolution with lexicase selection toward global solutions.

Molecular Evolution of the Glutathione S-Transferase Family in the Bemisia tabaci Species Complex.

The glutathione S-transferase (GST) family plays an important role in the adaptation of herbivorous insects to new host plants and other environmental constrains. The family codes for enzymes that neutralize reactive oxygen species and phytotoxins through the conjugation of reduced glutathione. Here, we studied the molecular evolution of the GST family in Bemisia tabaci, a complex of >35 sibling species, differing in their geographic and host ranges. We tested if some enzymes evolved different functionality, by comparing their sequences in six species, representing five of the six major genetic clades in the complex. Comparisons of the nonsynonymous to synonymous substitution ratios detected positive selection events in 11 codons of 5 cytosolic GSTs. Ten of them are located in the periphery of the GST dimer, suggesting a putative involvement in interactions with other proteins. Modeling the tertiary structure of orthologous enzymes, identified additional 19 mutations in 9 GSTs, likely affecting the enzymes’ functionality. Most of the mutation events were found in the environmentally responsive classes Delta and Sigma, indicating a slightly different delta/sigma tool box in each species. At a broader genomic perspective, our analyses indicated a significant expansion of the Delta GST class in B. tabaci and a general association between the diet breadth of hemipteran species and their total number of GST genes. We raise the possibility that at least some of the identified changes improve the fitness of the B. tabaci species carrying them, leading to their better adaptation to specific environments.

Detecting Regions At Risk for Spreading COVID-19 Using Existing Cellular Wireless Network Functionalities.

Goal: The purpose of this article is to introduce a new strategy to identify areas with high human density and mobility, which are at risk for spreading COVID-19. Crowded regions with actively moving people (called at-risk regions) are susceptible to spreading the disease, especially if they contain asymptomatic infected people together with healthy people. Methods: Our scheme identifies at-risk regions using existing cellular network functionalities—handover and cell (re)selection—used to maintain seamless coverage for mobile end-user equipment (UE). The frequency of handover and cell (re)selection events is highly reflective of the density of mobile people in the area because virtually everyone carries UEs. Results: These measurements, which are accumulated over very many UEs, allow us to identify the at-risk regions without compromising the privacy and anonymity of individuals. Conclusions: The inferred at-risk regions can then be subjected to further monitoring and risk mitigation.

Practical considerations in the use of regorafenib in metastatic colorectal cancer.

Over the past 20 years, management of patients with metastatic colorectal cancer (mCRC) has improved considerably, leading to increased overall survival and more patients eligible for third- or later-line therapy. Currently, two oral therapies are recommended in the third-line treatment of mCRC, regorafenib and trifluridine/tipiracil. Selecting the most appropriate treatment in the third-line setting poses different challenges compared with treatment selection at earlier stages. Therefore, it is important for physicians to understand and differentiate between available treatment options and to communicate the benefits and challenges of these to patients. In this narrative review, practical information on regorafenib is provided to aid physicians in their decision-making and patient communications in daily practice. We discuss the importance of appropriate patient selection and adverse events management through close patient monitoring and dose adjustments to ensure patients stay on treatment for longer and receive as much benefit as possible. We also highlight key physician–patient communication points to facilitate shared decision-making.

Intrinsically disordered regions are abundant in simplexvirus proteomes and display signatures of positive selection.

Whereas the majority of herpesviruses co-speciated with their mammalian hosts, human herpes simplex virus 2 (HSV-2, genus Simplexvirus) most likely originated from the cross-species transmission of chimpanzee herpesvirus 1 to an ancestor of modern humans. We exploited the peculiar evolutionary history of HSV-2 to investigate the selective events that drove herpesvirus adaptation to a new host. We show that HSV-2 intrinsically disordered regions (IDRs)—that is, protein domains that do not adopt compact three-dimensional structures—are strongly enriched in positive selection signals. Analysis of viral proteomes indicated that a significantly higher portion of simplexvirus proteins is disordered compared with the proteins of other human herpesviruses. IDR abundance in simplexvirus proteomes was not a consequence of the base composition of their genomes (high G + C content). Conversely, protein function determines the IDR fraction, which is significantly higher in viral proteins that interact with human factors. We also found that the average extent of disorder in herpesvirus proteins tends to parallel that of their human interactors. These data suggest that viruses that interact with fast-evolving, disordered human proteins, in turn, evolve disordered viral interactors poised for innovation. We propose that the high IDR fraction present in simplexvirus proteomes contributes to their wider host range compared with other herpesviruses.

Compass SPMD: a SPMD vectorized tracking algorithm

Compass is a SPMD (Single Program Multiple Data) tracking algorithm for the upcoming LHCb upgrade in 2021. 40 Tb/s need to be processed in real-time to select events. Alternative frameworks, algorithms and architectures are being tested to cope with the deluge of data. Allen is a research and development project aiming to run the full HLT1 (High Level Trigger) on GPUs (Graphics Processing Units). Allen’s architecture focuses on data-oriented layout and algorithms to better exploit parallel architectures. GPUs already proved to exploit the framework efficiently with the algorithms developed for Allen, implemented and optimized for GPU architectures. We explore opportunities for the SIMD (Single Instruction Multiple Data) paradigm in CPUs through the Compass algorithm. We use the Intel SPMD Program Compiler (ISPC) to achieve good readability, maintainability and performance writing “GPU-like” source code, preserving the main design of the algorithm.

In den „geheimen Gärten“ der Vorauswahl. Variationen der Listenaufstellung von CDU und SPD zum 19. Deutschen Bundestag

Intra-party selection procedures that precede the conference to nominate a party list are substantively understudied . Yet, they are of utmost importance to explain and evaluate what happens at the formal selection events . This study investigates the pre-selection activities in the run-up to the 2017 Bundestag election in the Christian Democratic Party (CDU) and the Social Democratic Party (SPD) . Drawing on participant observations as well as survey and interview data, it reveals that both parties use diverse multi-stage processes that in part predetermine the subsequent nomination results . Moreover, the party’s executive boards at state level can influence list nominations to varying degrees . In some cases, the formal selectorates clearly overestimate the leadership’s power . Although the selection procedures can be regarded as a sign of a vital intra-party democracy, parties should think about formalizing them in their statutes . The widespread informal decision making entails a lack of transparency even among party members and candidacy aspirants .