Proposal for standardization of laparoscopic D3 lymphadenectomy for right colon cancer.

BACKGROUND: This study presents a laparoscopic surgical protocol for right hemicolectomy and D3 lymphadenectomy (R-D3L) in right colon cancer and reports the oncological outcomes based on a prospective series. METHODS: The study comprises two phases. In the first phase, a dynamic demonstration of the R-D3L surgical protocol is provided through textual explanation, illustrations, and edited surgical videos. The protocol emphasizes technical steps such as dissection of the embryological plane of the right mesocolon, high tie of ileocolic vessels, surgical trunk of Gillot dissection, and high tie of superior right colic vein (SRCV). In the second phase, a prospective observational study was conducted involving patients undergoing R-D3L surgery with this protocol between July 2015 and July 2021. Demographic, perioperative, and postoperative variables are analyzed, along with anatomopathological variables and oncological outcomes. RESULTS: A total of 33 patients were analyzed. Median operative time was 202 min. Perioperative bleeding occurred in 6%. Postoperative complications were mild (Clavien-Dindo III in 2%). Postoperative ileus was observed in 15%. No anastomotic dehiscence was reported. The median postoperative stay was 7 days. The median number of resected lymph nodes was 26, with 27% having positive nodes and 70% were classified as stage T3 or T4. After a median follow-up of 45 months, local recurrence, distant recurrence, and carcinomatosis rates were 0%. Mortality rate from other causes was 9%. CONCLUSION: The surgical protocol shown in the present study could help in the implementation of this technique in those units that consider it appropriate.

Genome-wide SNP assessment of contemporary European red deer genetic structure highlights the distinction of peripheral populations and the main admixture zones in Europe.

Genome-wide technologies open up new possibilities to clarify questions on genetic structure and phylogeographic history of taxa previously studied with microsatellite loci and mitochondrial sequences. Here, we used 736 individual red deer (Cervus elaphus) samples genotyped at 35,701 single nucleotide polymorphism loci (SNPs) to assess the population structure of the species throughout Europe. The results identified 28 populations, with higher degrees of genetic distinction in peripheral compared to mainland populations. Iberian red deer show high genetic differentiation, with lineages in Western and Central Iberia maintaining their distinctiveness, which supports separate refugial ranges within Iberia along with little recent connection between Iberian and the remaining Western European populations. The Norwegian population exhibited the lowest variability and the largest allele frequency differences from mainland European populations, compatible with a history of bottlenecks and drift during post-glacial colonization from southern refugia. Scottish populations showed high genetic distance from the mainland but high levels of diversity. Hybrid zones were found between Eastern and Western European lineages in Central Europe as well as in the Pyrenees, where red deer from France are in close contact with Iberian red deer. Anthropogenic restocking has promoted the Pyrenean contact zone, admixture events in populations on the Isle of Rum and in the Netherlands, and at least partly the admixture of the two main lineages in central-eastern Europe. Our analysis enabled detailed resolution of population structure of a large mammal widely distributed throughout Europe and contributes to resolving the evolutionary history, which can also inform conservation and management policies.

Selection leads to remarkable variability in the outcomes of hybridisation across replicate hybrid zones.

Hybrid zones have been viewed as an opportunity to see speciation in action. When hybrid zones are replicated, it is assumed that if the same genetic incompatibilities are maintaining reproductive isolation across all instances of secondary contact, those incompatibilities should be identifiable by consistent patterns in the genome. In contrast, changes in allele frequencies due to genetic drift should be idiosyncratic for each hybrid zone. To test this assumption, we simulated 20 replicates of each of 12 hybrid zone scenarios with varied genetic incompatibilities, rates of migration, selection and different starting population size ratios of parental species. We found remarkable variability in the outcomes of hybridisation in replicate hybrid zones, particularly with Bateson-Dobzhansky-Muller incompatibilities and strong selection. We found substantial differences among replicates in the overall genomic composition of individuals, including admixture proportions, inter-specific ancestry complement and number of ancestry junctions. Additionally, we found substantial variation in genomic clines among replicates at focal loci, regardless of locus-specific selection. We conclude that processes other than selection are responsible for some consistent outcomes of hybridisation, whereas selection on incompatibilities can lead to genomically widespread and highly variable outcomes. We highlight the challenge of mapping between pattern and process in hybrid zones and call attention to how selection against incompatibilities will commonly lead to variable outcomes. We hope that this study informs future research on replicate hybrid zones and encourages further development of statistical techniques, theoretical models and exploration of additional axes of variation to understand reproductive isolation.

Anthropogenic Change and the Process of Speciation.

Anthropogenic impacts on the environment alter speciation processes by affecting both geographical contexts and selection patterns on a worldwide scale. Here we review evidence of these effects. We find that human activities often generate spatial isolation between populations and thereby promote genetic divergence but also frequently cause sudden secondary contact and hybridization between diverging lineages. Human-caused environmental changes produce new ecological niches, altering selection in diverse ways that can drive diversification; but changes also often remove niches and cause extirpations. Human impacts that alter selection regimes are widespread and strong in magnitude, ranging from local changes in biotic and abiotic conditions to direct harvesting to global climate change. Altered selection, and evolutionary responses to it, impacts early-stage divergence of lineages, but does not necessarily lead toward speciation and persistence of separate species. Altogether, humans both promote and hinder speciation, although new species would form very slowly relative to anthropogenic hybridization, which can be nearly instantaneous. Speculating about the future of speciation, we highlight two key conclusions: (1) Humans will have a large influence on extinction and "despeciation" dynamics in the short term and on early-stage lineage divergence, and thus potentially speciation in the longer term, and (2) long-term monitoring combined with easily dated anthropogenic changes will improve our understanding of the processes of speciation. We can use this knowledge to preserve and restore ecosystems in ways that promote (re-)diversification, increasing future opportunities of speciation and enhancing biodiversity.

Diverse data sources and new statistical models offer prospects for improving the predictability of anthropogenic hybridization.

Human disturbance can theoretically influence the rates of hybridization, but few studies have convincingly identified a causal link. Grabenstein et al. (2022) used a genomic and phenotypic study of chickadees to associate hybridization with human disturbance. Additionally, this is consistent with citizen science reports of chickadee hybrids across the range. We highlight the exciting aspects of this work and make suggestions about a role for broad geographic and genomic sampling, and new statistical methods to better connect hybridization outcomes to anthropogenic disturbance in diverse study systems.

Who moves in vulnerable Caribbean neighborhoods? Positive deviance for physical activity: Findings from the Jamaica health and Lifestyle Survey 2017 (JHLS III).

Decreased physical activity (PA) has been associated with residents living in neighborhoods perceived as being disordered or having high crime levels. What is unknown are the characteristics of individuals who engage in moderate to vigorous levels of PA (MVPA) despite living in these vulnerable neighborhoods, or who may be referred to as positive deviants (PD). We examined the factors associated with PD for PA among Jamaicans. Between 2016 and 2017 the Jamaica Health and Lifestyle Survey, a cross-sectional nationally representative survey (n = 2807), was conducted on individuals aged 15 years and older. Regression analyses were performed to identify associations with PD, defined using engagement in MVPA among persons living in vulnerable neighborhoods (N = 1710). Being female (odds ratio [OR]a = 0.64 (0.48, 0.86); p = 0.003), obese while living in an urban area (ORa = 0.39; 95 % CI = 0.26, 0.59; p < 0.0001), unemployed (ORa = 0.53; 95 % CI = 0.39, 0.73; p < 0.0001), or a student (ORa = 0.62; 95 % CI = 0.39, 0.98); p = 0.041) was associated with a significantly lower likelihood of PD, while having a personal medical history of at least one chronic disease significantly increased likelihood (ORa = 1.43; 95 % CI = 1.08, 1.90; p = 0.014). Taking a PD approach may be one angle to consider in trying to determine what is working and for whom, so that this may be harnessed in policy, prevention and intervention programming to increase PA.

Expanding indication of laparoscopic intracorporeal rectus aponeuroplasty (LIRA) to suprapubic area: LIRA & TAPE / Indicación extendida de la aponeuroplastia intracorpórea de rectos laparoscópica (LIRA) al área suprapúbica: LIRA & TAPE

Laparoscopic intracorporeal rectus aponeuroplasty (LIRA) is a minimally invasive technique described to repair M2–M4 primary and incisional hernias. Defects below this area (M5 – Suprapubic area) could be treated using the concept associated to LIRA, expanding the indication of this technique in combination with a transabdominal partially extraperitoneal (TAPE) repair. The aim of this video is to show the surgical steps in the combination of LIRA & TAPE for M2–M5 ventral hernias (AU)

La aponeuroplastia intracorpórea de rectos laparoscópica (LIRA) es una técnica mínimamente invasiva para la reparación de las hernias incisionales de M2 a M4. Los defectos por debajo de esta zona (M5 – área suprapúbica) se pueden reparar mediante una indicación extendida de LIRA combinada con la reparación transabdominal parcialmente extraperitoneal (TAPE). El objetivo de este video es demostrar los pasos quirúrgicos en la combinación de LIRA & TAPE para hernias ventrales de M2 a M5 (AU)

Admixture mapping reveals loci for carcass mass in red deer x sika hybrids in Kintyre, Scotland.

We deployed admixture mapping on a sample of 386 deer from a hybrid swarm between native red deer (Cervus elaphus) and introduced Japanese sika (Cervus nippon) sampled in Kintyre, Scotland to search for quantitative trait loci (QTLs) underpinning phenotypic differences between the species. These two species are highly diverged genetically [Fst between pure species, based on 50K single nucleotide polymorphism (SNPs) = 0.532] and phenotypically: pure red have on average twice the carcass mass of pure sika in our sample (38.7 kg vs 19.1 kg). After controlling for sex, age, and population genetic structure, we found 10 autosomal genomic locations with QTL for carcass mass. Effect sizes ranged from 0.191 to 1.839 kg and as expected, in all cases the allele derived from sika conferred lower carcass mass. The sika population was fixed for all small carcass mass alleles, whereas the red deer population was typically polymorphic. GO term analysis of genes lying in the QTL regions are associated with oxygen transport. Although body mass is a likely target of selection, none of the SNPs marking QTL are introgressing faster or slower than expected in either direction.

Low Heritability but Significant Early Environmental Effects on Resting Metabolic Rate in a Wild Passerine.

AbstractPredicting the impact of climate change on biodiversity requires understanding the adaptation potential of wild organisms. Evolutionary responses depend on the additive genetic variation associated with the phenotypic traits targeted by selection. We combine 5 years of cross-fostering experiments, measurements of resting metabolic rate (RMR) on nearly 200 wild collared flycatcher (Ficedula albicollis) nestlings, and animal models using a 17-year pedigree to evaluate the potential for an evolutionary response to changing environmental conditions. Contrary to other avian studies, we find no significant heritability of whole-organism, mass-independent, or mass-specific RMR, but we report a strong effect of nest environment instead. We therefore conclude that variation in nestling RMR is explained by variation in the early-life environment provided by the parents. We discuss possible underlying specific parental effects and the importance of taking different mechanisms into account to understand how animals phenotypically adapt (or fail to adapt) to climate change.

Locus-specific introgression in young hybrid swarms: Drift may dominate selection.

Closely related species that have previously inhabited geographically separated ranges are hybridizing at an increasing rate due to human disruptions. These human-mediated hybrid zones can be used to study reproductive isolation between species at secondary contact, including examining locus-specific rates of introgression. Introgression is expected to be heterogenous across the genome, reflecting variation in selection. Those loci that introgress especially slowly are good candidates for being involved in reproductive isolation, while those loci that introgress quickly may be involved in adaptive introgression. In the context of conservation, policy makers are especially concerned about introduced alleles moving quickly into the background of a native or endemic species, as these alleles could replace the native alleles in the population, leading to extinction via hybridization. We applied genomic cline analyses to 44,997 SNPs to identify loci introgressing more or less when compared to the genome wide expectation in a human-mediated hybridizing population of red deer and sika in Kintyre Scotland. We found 11.4% of SNPs had cline centres that were significantly different from the genome wide expectation, and 17.6% of all SNPs had excess rates of introgression. Based on simulations, we believe that many of these markers have diverged from the genome-wide average due to drift, rather than because of selection, and we suggest that these simulations can be useful as a null distribution for future studies of genomic clines. Future work on red deer and sika could determine the policy implications of allelic-replacement due to drift rather than selection, and could use replicate, geographically distinct hybrid zones to narrow down those loci that are responding to selection.

Fluctuating optimum and temporally variable selection on breeding date in birds and mammals.

Temporal variation in natural selection is predicted to strongly impact the evolution and demography of natural populations, with consequences for the rate of adaptation, evolution of plasticity, and extinction risk. Most of the theory underlying these predictions assumes a moving optimum phenotype, with predictions expressed in terms of the temporal variance and autocorrelation of this optimum. However, empirical studies seldom estimate patterns of fluctuations of an optimum phenotype, precluding further progress in connecting theory with observations. To bridge this gap, we assess the evidence for temporal variation in selection on breeding date by modeling a fitness function with a fluctuating optimum, across 39 populations of 21 wild animals, one of the largest compilations of long-term datasets with individual measurements of trait and fitness components. We find compelling evidence for fluctuations in the fitness function, causing temporal variation in the magnitude, but not the direction of selection. However, fluctuations of the optimum phenotype need not directly translate into variation in selection gradients, because their impact can be buffered by partial tracking of the optimum by the mean phenotype. Analyzing individuals that reproduce in consecutive years, we find that plastic changes track movements of the optimum phenotype across years, especially in bird species, reducing temporal variation in directional selection. This suggests that phenological plasticity has evolved to cope with fluctuations in the optimum, despite their currently modest contribution to variation in selection.

Tissue-specific patterns of regulatory changes underlying gene expression differences among Ficedula flycatchers and their naturally occurring F1 hybrids.

Changes in interacting cis- and trans-regulatory elements are important candidates for Dobzhansky-Muller hybrid incompatibilities and may contribute to hybrid dysfunction by giving rise to misexpression in hybrids. To gain insight into the molecular mechanisms and determinants of gene expression evolution in natural populations, we analyzed the transcriptome from multiple tissues of two recently diverged Ficedula flycatcher species and their naturally occurring F1 hybrids. Differential gene expression analysis revealed that the extent of differentiation between species and the set of differentially expressed genes varied across tissues. Common to all tissues, a higher proportion of Z-linked genes than autosomal genes showed differential expression, providing evidence for a fast-Z effect. We further found clear signatures of hybrid misexpression in brain, heart, kidney, and liver. However, while testis showed the highest divergence of gene expression among tissues, it showed no clear signature of misexpression in F1 hybrids, even though these hybrids were found to be sterile. It is therefore unlikely that incompatibilities between cis-trans regulatory changes explain the observed sterility. Instead, we found evidence that cis-regulatory changes play a significant role in the evolution of gene expression in testis, which illustrates the tissue-specific nature of cis-regulatory evolution bypassing constraints associated with pleiotropic effects of genes.

Differences in incubation behaviour and niche separation of two competing flycatcher species.

ABSTRACT: Food availability sets the stage for incubation behaviour of a female bird and thereby indirectly determines the nest temperature, which in turn affects development and metabolism of avian embryos. Changes in development and metabolism in turn are known to influence offspring's ability to adjust to environmental changes later in life. However, few studies have investigated the role of interspecific differences in incubation behaviour in relation to niche separation between competing sibling species. We studied the effects of habitat quality (in terms of caterpillar availability) on incubation behaviour of two ecologically similar and closely related species, collared and pied flycatchers (Ficedula albicollis and F. hypoleuca), in their hybrid zone on the island of Öland, Sweden. Even though both species prefer caterpillar-rich deciduous forests as nesting sites, collared flycatchers, whose nestlings have higher energetic demands, are able to nest only in deciduous forests, whereas pied flycatchers have more flexible habitat requirements. Overall, higher food availability was associated with increased nest attendance, higher incubation temperature and a lower number of foraging trips across species. In addition, collared flycatchers had more frequent and shorter foraging trips across habitat types, allocated more heat to eggs and therefore maintained higher nest temperatures compared to pied flycatchers. We argue that the higher heat allocation or the need to maintain a higher nest temperature for embryo development may constrain collared flycatchers to focus on relatively more profitable prey. Our results highlight the importance of considering incubation behaviour in the context of understanding species differences in niche use. SIGNIFICANCE STATEMENT: Niche separation plays an important role in mitigating effects of competition between closely related species. Whether species differences in incubation behaviour relate to differences in niche use remains unknown. We compared incubation behaviour of two sympatric flycatcher species that differ in sensitivity to food availability. The competitively more dominant and larger species, the collared flycatcher, whose nestlings are more sensitive to food shortages, made more frequent foraging trips but allocated more heat to eggs, leading to higher nest temperature despite lower nest attendance, compared to pied flycatchers. These interspecific differences may be a result of differences in embryo sensitivity or female physiology and contribute to the niche separation between the species, which in turn can facilitate coexistence.

Increased genetic marker density reveals high levels of admixture between red deer and introduced Japanese sika in Kintyre, Scotland.

Hybridization is a natural process at species range boundaries, but increasing numbers of species are hybridizing due to direct or indirect human activities. In such cases of anthropogenic hybridization, subsequent introgression can threaten the survival of native species. To date, many such systems have been studied with too few genetic markers to assess the level of threat resulting from advanced backcrossing. Here, we use 44,999 single nucleotide polymorphisms (SNPs) and the ADMIXTURE program to study two areas of Scotland where a panel of 22 diagnostic microsatellites previously identified introgression between native red deer (Cervus elaphus) and introduced Japanese sika (Cervus nippon). In Kintyre, we reclassify 26% of deer from the pure species categories to the hybrid category whereas in the NW Highlands we only reclassify 2%. As expected, the reclassified individuals are mostly advanced backcrosses. We also investigate the ability of marker panels selected on different posterior allele frequency criteria to find hybrids assigned by the full marker set and show that in our data, ancestry informative markers (i.e. those that are highly differentiated between the species, but not fixed) are better than diagnostic markers (those markers that are fixed between the species) because they are more evenly distributed in the genome. Diagnostic loci are concentrated on the X chromosome to the detriment of autosomal coverage.

Detecting the True Extent of Introgression during Anthropogenic Hybridization.

Hybridization among naturally separate taxa is increasing owing to human impact, and can result in taxon loss. Previous classification of anthropogenic hybridization has largely ignored the case of bimodal hybrid zones, in which hybrids commonly mate with parental species, resulting in many backcrossed individuals with a small proportion of introgressed genome. Genetic markers can be used to detect such hybrids, but until recently too few markers have been used to detect the true extent of introgression. Recent studies of wolves and trout have employed thousands of markers to reveal previously undetectable backcrosses. This improved resolution will lead to increased detection of late-generation backcrosses, shed light on the consequences of anthropogenic hybridization, and pose new management issues for conservation scientists.