The Dynamics of Adaptation to Stress from Standing Genetic Variation and de novo Mutations.

Adaptation from standing genetic variation is an important process underlying evolution in natural populations, but we rarely get the opportunity to observe the dynamics of fitness and genomic changes in real time. Here, we used experimental evolution and Pool-Seq to track the phenotypic and genomic changes of genetically diverse asexual populations of the yeast Saccharomyces cerevisiae in four environments with different fitness costs. We found that populations rapidly and in parallel increased in fitness in stressful environments. In contrast, allele frequencies showed a range of trajectories, with some populations fixing all their ancestral variation in <30 generations and others maintaining diversity across hundreds of generations. We detected parallelism at the genomic level (involving genes, pathways, and aneuploidies) within and between environments, with idiosyncratic changes recurring in the environments with higher stress. In particular, we observed a tendency of becoming haploid-like in one environment, whereas the populations of another environment showed low overall parallelism driven by standing genetic variation despite high selective pressure. This work highlights the interplay between standing genetic variation and the influx of de novo mutations in populations adapting to a range of selective pressures with different underlying trait architectures, advancing our understanding of the constraints and drivers of adaptation.

Combining Experimental Evolution and Genomics to Understand How Seed Beetles Adapt to a Marginal Host Plant.

Genes that affect adaptive traits have been identified, but our knowledge of the genetic basis of adaptation in a more general sense (across multiple traits) remains limited. We combined population-genomic analyses of evolve-and-resequence experiments, genome-wide association mapping of performance traits, and analyses of gene expression to fill this knowledge gap and shed light on the genomics of adaptation to a marginal host (lentil) by the seed beetle Callosobruchus maculatus. Using population-genomic approaches, we detected modest parallelism in allele frequency change across replicate lines during adaptation to lentil. Mapping populations derived from each lentil-adapted line revealed a polygenic basis for two host-specific performance traits (weight and development time), which had low to modest heritabilities. We found less evidence of parallelism in genotype-phenotype associations across these lines than in allele frequency changes during the experiments. Differential gene expression caused by differences in recent evolutionary history exceeded that caused by immediate rearing host. Together, the three genomic datasets suggest that genes affecting traits other than weight and development time are likely to be the main causes of parallel evolution and that detoxification genes (especially cytochrome P450s and beta-glucosidase) could be especially important for colonization of lentil by C. maculatus.

Dynamics of genomic change during evolutionary rescue in the seed beetle Callosobruchus maculatus.

Rapid adaptation can prevent extinction when populations are exposed to extremely marginal or stressful environments. Factors that affect the likelihood of evolutionary rescue from extinction have been identified, but much less is known about the evolutionary dynamics (e.g., rates and patterns of allele frequency change) and genomic basis of successful rescue, particularly in multicellular organisms. We conducted an evolve-and-resequence experiment to investigate the dynamics of evolutionary rescue at the genetic level in the cowpea seed beetle, Callosobruchus maculatus, when it is experimentally shifted to a stressful host plant, lentil. Low survival (~1%) at the onset of the experiment caused population decline. But adaptive evolution quickly rescued the population, with survival rates climbing to 69% by the F5 generation and 90% by the F10 generation. Population genomic data showed that rescue likely was caused by rapid evolutionary change at multiple loci, with many alleles fixing or nearly fixing within five generations of selection on lentil. Selection on these loci was only moderately consistent in time, but parallel evolutionary changes were evident in sublines formed after the lentil line had passed through a bottleneck. By comparing estimates of selection and genomic change on lentil across five independent C. maculatus lines (the new lentil-adapted line, three long-established lines and one case of failed evolutionary rescue), we found that adaptation on lentil occurred via somewhat idiosyncratic evolutionary changes. Overall, our results suggest that evolutionary rescue in this system can be caused by very strong selection on multiple loci driving rapid and pronounced genomic change.

Sources of Variation in the Gut Microbial Community of Lycaeides melissa Caterpillars.

Microbes can mediate insect-plant interactions and have been implicated in major evolutionary transitions to herbivory. Whether microbes also play a role in more modest host shifts or expansions in herbivorous insects is less clear. Here we evaluate the potential for gut microbial communities to constrain or facilitate host plant use in the Melissa blue butterfly (Lycaeides melissa). We conducted a larval rearing experiment where caterpillars from two populations were fed plant tissue from two hosts. We used 16S rRNA sequencing to quantify the relative effects of sample type (frass versus whole caterpillar), diet (plant species), butterfly population and development (caterpillar age) on the composition and diversity of the caterpillar gut microbial communities, and secondly, to test for a relationship between microbial community and larval performance. Gut microbial communities varied over time (that is, with caterpillar age) and differed between frass and whole caterpillar samples. Diet (host plant) and butterfly population had much more limited effects on microbial communities. We found no evidence that gut microbe community composition was associated with caterpillar weight, and thus, our results provide no support for the hypothesis that variation in microbial community affects performance in L. melissa.

Canine mammary tumors in Santos, Brazil: clinicopathological and survival profile / Neoplasias mamárias caninas em Santos, Brasil: perfil clinicopatológico e de sobrevida

Tumors of the mammary glands are the most common neoplasms in dogs in our country; however, there are few Brazilian reports dedicated to clinicopathological and survival studies about this disease. This report aims the clinical and pathological study of canine mammary tumors in the Santos Metropolitan Region, an area in Sao Paulo state with an estimated canine population of 120,000 animals. Data of 14,298 dogs were collected retrospectively from the medical records of the Veterinary Medical Teaching Hospital of the Metropolitan University of Santos – São Paulo – Brazil. During the study period, from records of 317 females with histopathological diagnosis of neoplasia, 170 were mammary epithelial lesions distributed in 13 benign tumors, 152 malignant (89.4% of diagnosis) and 5 non-neoplasic epithelial lesions (ductal hyperplasia). The highest prevalent malignant tumor was tubular carcinoma (38.2% of diagnosis) and Grade I tumors, corresponding to 73.0% of all diagnosis. The results have shown clinical staging of canine mammary neoplasms as an important prognostic survival factor and, in a multivariate analysis, tumor diameter, tumor grade, adjuvant chemotherapy and recurrence as covariates with predictive value for survival. Moreover, the high prevalence of tubular carcinoma qualifies the canine population of Santos as a promising model for the translational study of this disease.

Os tumores das glândulas mamárias são as neoplasias mais comuns em cadelas em nosso país; no entanto, são poucos os trabalhos brasileiros dedicados ao estudo clinicopatológico e de sobrevida nesta doença. O presente trabalho teve por objetivo o estudo clínico e patológico dos tumores mamários caninos na Região Metropolitana de Santos, uma área no estado de São Paulo com uma população canina estimada em 120 mil animais. Dados de 14.298 cães foram coletados retrospectivamente dos prontuários médicos do Hospital Veterinário da Universidade Metropolitana de Santos – São Paulo – Brasil. Durante o período do estudo, foram atendidas 317 fêmeas com diagnóstico histopatológico de neoplasia, dos quais, 170 se referiam a lesões mamárias epiteliais distribuídas em 13 tumores benignos, 152 malignos (89,4% dos diagnósticos) e 5 lesões epiteliais não-neoplásicas (hiperplasia ductal). O tumor mais frequente foi o carcinoma tubular (38,2% dos tumores malignos) e tumores de grau I, respondendo por 73,0% do total diagnosticado. Estudos de sobrevida apontaram para o estadiamento clínico das neoplasias mamárias caninas como importante fator prognóstico, e na análise multivariada, diâmetro do tumor, grau histológico, quimioterapia adjuvante e recorrência apresentaram-se como covariáveis com valor preditivo de sobrevida. Levando-se em conta a elevada prevalência de carcinoma tubular simples na população canina de Santos, pode-se considerá-la como promissor modelo translacional para o estudo da doença.

Necropsy findings in dogs that died during grooming or other pet service procedures.

Procedures involved in grooming, bathing, and other pet services can often lead animals to death. Of the necropsies of 1391 animals carried out at a private diagnostic laboratory in Sao Paulo, Brazil from 2004 to 2009, 94 were dogs that died during the above-mentioned procedures. Young male dogs and small breeds like Poodle Miniature, Yorkshire Terrier, and Lhasa Apso were most frequently observed. Blunt-force trauma was responsible for the deaths of 31% of the animals, with a higher incidence of trauma to the head, characterized chiefly by fractures and nervous tissue lesions. In the other 69% of cases, the animals showed signs of stress, and died due to pulmonary edema and hemorrhage. As we cannot rule out the intentional character in some situations, this article provides veterinary forensic support for veterinarians and pet owners, especially in lawsuits, helping in finding the cause of animal's death in such pet services.

Análise comparativa entre métodos de previsão das dimensões mesio-distais de caninos e pré-molares não irrompidos durante a fase de dentição mista / Comparative analysis of forecasting methods mesiodistal dimensions of canines and premolars not erupted during the mixed dentition

O objetivo deste trabalho foi avaliar e comparar, aos diferentes métodos, o prognóstico do espaço requerido para caninos e pré-molares permanentes inferiores, por meio de mensurações em telerradiografias à 45 graus para ambos lados, radiografias panorâmicas e em modelos de estudo. Foram utilizados pacientes jovens, brasileiros, de ambos os gêneros, selecionados de documentações ortodônticas já existentes, pertencentes ao arquivo de clínica particular. Fizeram parte os indivíduos que possuíam dentição mista e apresentavam caninos e pré-molares permanentes em estágio de formação e não irrompidos. Estas documentações são compostas de modelos e das radiografias. Inicialmente, foram medidas as larguras do canino, primeiro e segundo molares decíduos em ambos os lados nos modelos de estudo, utilizando-se de um compasso com pontas secas e transportadas a um paquímetro digital para obter as medidas em milímetros. Em adição, foram medidas, da mesma forma, as larguras mésio-distais dos dentes localizados na região anterior, caninos e pré-molares permanentes nas radiografias, em ambos os lados. Foram separados os dados que se apresentavam nos três métodos de avaliação e aplicado à estatística. Os resultados mostraram que as avaliações foram semelhantes entre si. Com relação à avaliação comparativa entre os métodos modelo; telerradiografia 45 graus e da radiografia panorâmica somente na comparação entre os métodos modelo e telerradiografia 45 graus a diferença foi estatisticamente pouco significante. Na comparação com os quatro métodos da literatura, os métodos foram similares. Pode-se concluir que o método que mais se aproximou das medidas reais para os dentes permanentes não irrompidos foi a telerradiografia 45 graus corrigida.

The aim of this search was evaluated and compared by different methods the prognostic of the space necessary to lowers canines and premolars, using cephalometric lateral radiographs in 45 degree for both sides, panoramic radiographies and studies models. Young Brazilian both gender’s patients were used and selected existent handbooks by particular clinical archive. Individual that had mix dentition and permanents canines and premolars, in formation stages and no eruption, were selected. These handbooks are composed by studies models and radiographies. Initially, in both sides, width of deciduous canines, first and second molars were measured in studies models using a dry compass and transporting to a digital pachymeter to obtain the measures in millimeters. In addiction, using the same measure method, in both sides, the mesio-distal width of the permanents teeth localizing in anterior region, canines and premolars in radiographies were considered. The data that appeared in the three methods of evaluation was separated and applied the statistical analysis. The results showed that the evaluation was similar. In relation with a comparative analysis between the methods, only the comparison between the model’s method and cephalometric radiographies in 45 degrees was statistically insignificant. It’s possible to conclude that the method that was more proximal than real values for the no eruption permanent teeth was the revised cephalometric radiographies in 45 degrees