Exploring the potential of genetic improvement of insects : a case study using the haplodiploid parasitoid wasp Nasonia vitripennis

Insects have gained increasing interests in diverse agricultural applications, ranging from the use of insect-derived protein in animal feed to the use of insects as natural enemies of agricultural pests. Using the knowledge of genetics is a powerful way to improve the application of insects in agriculture. The exploitation of genetic variation in insects has been discussed for long time, however, the nature of genetic variation is still largely unexplored for insects outside of well-studies species. The main aim of this thesis was to explore the potential of genetic improvement of insects. To this end, I investigated the genetic basis of wing morphology and associated phenotypic traits in the parasitoid wasp Nasonia vitripennis as a case study. First, I used a modified Animal Model with a pedigree relationship matrix, and the Genomic Restricted Maximum Likelihood method to quantify the amount of genetic variation and variation due to host effects for these traits. Host effects occur because Nasonia species are gregarious wasps, which lay more than one egg into a single host, so that the offspring share a common developmental environment. The results have shown substantial host effects on wing morphology traits, especially for size traits: hosts explained up to 64% of the total phenotypic variation. Significant additive genetic variation were also observed for all traits. Second, I conducted genome-wide association study (GWAS) to further reveal the genetic basis of these traits. Several genomic regions that significantly associated with wing morphology variation were identified. Third, I implemented genomic prediction for wing morphology traits in N. vitripennis to explore its potential in insects. The results have showed promising accuracies based on a cross-validation strategy, which suggests that genomic prediction is feasible in insects. Furthermore, I investigated the relationship between the level of inbreeding and inbreeding depression for wing morphology traits using sex-biased gene expression. I found no evidence for a relationship between inbreeding and sex-biased gene expression, and I did not observe any inbreeding depression for wing morphology traits. Finally, I discussed the potential of improvement of insect parasitoids by selecting better hosts and the implications of the exploration of genetic variation for potential applications in insects selective breeding. Together, this thesis provides important insights into the genetic architecture of wing morphology in the parasitoid wasp Nasonia vitripennis. The findings contribute to the knowledge of the genetic basis of wing morphology traits in insects, and also show the promising potential of using genetic tools to improve insects

Genotype by environment interaction for sexual maturity in Atlantic salmon (Salmo salar)

Genetic parameters and genotype by environment interactions were estimated for early sexual maturity in Atlantic salmon. About 23984 (24999) individuals from 115 (118) full-sib families were tested in six sea-cages at five different locations in Norway. After 15 to 16 months in the sea, all individuals were classified for indications of maturation. Large variation in percentage of maturing were observed at different farms for two year-classes . The heritabilities estimated for early sexual maturity ranged from 0.02 to 0.11 on observed scales, and varied from 0.04 to 0.21 on liability scale. Besides, the heritability estimates on observed scale were roughly two times higher than those on the linear scale. The effects common to full-sibs other than additive genetic effects accounted for less than 5% of the total phenotypic variance on observed scale and less than 7% on liability scale . Gentic correlation were estimated between pairs of test environments, for 0.67 to 0.99 in year-class 1983, and 0.36 to 0.99 in year-class 1987. Most estimates of genetic correlation were significantly different from unity which indicated the presence of genotype by environment interaction. The low and significant correlations of effects common to full-sibs were estimated which indicates the effects common to full-sibs became smaller after separating into production environments. The genetic gain was calculated based on estimated breeding values of full-sib families, and unfavorable genetic gains were observed in present study both for expect gain and and realized gain.M-A

A New Theoretical View of Rockburst and Its Engineering Application

Traditionally, rockburst is considered as a dynamic phenomenon of sudden destruction of coal/rock mass. In this study, rockburst is treated as an event process rather than a phenomenon. This paper introduces typical rockburst process, its classification, mechanism of internal and external causes, and energy criterion. Analysis indicates that rockburst is a dynamic process that includes three sequential phases: burst start-up, burst energy transfer, and rockburst pressure behavior. Excessive static stress concentration in the strata nearby the target zone appears to be the internal cause of rockburst start-up, while the external cause is the disturbance of the static stress concentration and additional load transfer by the concentrated dynamic load occurred at further distance. Potential burst start-up area is the highest stress concentration zone within the region where stress is in the critical equilibrium state. With the identified internal and external factors that contribute to rockburst start-up, it is concluded that the rockburst preventive measures should focus on the monitoring and controlling of originating source of static and dynamic stress concentrations. Field practice proves that the reunderstanding of rockburst and the derived preventive measures are feasible and successful

A comparative analysis of US toll policy

In the US, there is a long tradition of toll roads, beginning with the Lancaster Turnpike that was built at the end of the 18th century connecting Philadelphia and Lancaster. There are currently more than 300 toll facilities in the US, which is probably the largest number of toll facilities in the world. These facilities represent a wide range of conditions, from hypercongested facilities in large metropolitan areas such as New York City to toll highways in rural areas. The toll structures are equally diverse, ranging from multi-tier price structures with frequent user, carpool, and time of day discounts; to simpler structures in which the only differentiation is made on the basis of the number of axles per vehicle. The toll rates are typically set by the agencies that operate or own the toll facilities. The rules or formulas by which these tolls are determined are not generally available to the public, though it is safe to say that toll decisions are made taking into account technical considerations, as well as the all important criterion of political acceptability. However, data on toll rates and how they change by vehicle types and by some other attributes are readily available. The overall objective of this paper is to analyze the toll data from various facilities across the US to gain insight into the overall factors affecting the tolls. A more specific objective is to assess--though in a rather approximate fashion--if the tolls by vehicle type, relative to each other, are appropriate and consistent with economic theory. This is achieved by comparing tolls to approximate indicators of road space consumption and pavement deterioration. The literature review confirmed that this is the first time such research has been conducted which is an important first step toward an analysis of the efficiency of current toll policies. The analyses in this paper are based on a random sample of all toll facilities across the US. The toll dataset, which include toll rates for passenger cars, busses, and three different truck types, is assembled mainly from the available information on the web sites of various toll agencies. After cleaning the data, the authors used econometric modeling to estimate a set of ordinary least squares (OLS) regression models that express tolls as functions of independent variables. Three families of models were estimated: linear models, models based on expansions of Taylor series, and models based on piece-wise linear approximations to non-linear effects. The resulting models were analyzed to identify the salient features of current toll policies towards different vehicle types.

Application Effect of Fast Track Surgery for Patients with Lung Cancer: A Meta-analysis

Background and objective Fast track surgery (FTS) can accelerate rehabilitation and reduce postoperative hospital stay. It has been effectively applied to several surgical diseases. However, the safety and effectiveness of FTS for patients with lung cancer in China is unclear. This meta-analysis aimed to evaluate the effect of FTS undergoing lung cancer surgery in China. Methods Using home and abroad databases to search all documents required. The deadline of retrieval was January 31, 2016. Then the studies were screened according to the inclusion and exclusion criteria. Data were analyzed by RevMan 5.3 software. Results 8 randomized controlled trials (RCTs) and 5 clinical controlled trials (CCTs) with 1,241 patients were eligible for analysis. Compared with control group, FTS group can significantly shorten postoperative hospital time (MD=-3.61, 95%CI: -5.05--2.16, P<0.000,01) and chest tube duration (MD=-2.62, 95%CI: -3.07-2.17, P<0.000,01), reduce incidence of postoperative complications (OR=0.30, 95%CI: 0.19-0.47, P<0.000,01) and hospitalization costs (MD=-0.92, 95%CI: -1.19--0.65, P<0.000,01). Conclusion FTS can safely and effectively accelerate the recovery of patients with lung cancer in China, it exhibits important clinical values

Occurrence law and classification prevention of rock burst in coal mines of Shaanxi Province

With coal resource extraction areas are constantly shifting towards the west and deeper regions, and the number of rock burst mines in the western region is increasing rapidly. As a major coal province, Shaanxi Province has a stable scale of coal development and supply, ranking among the top in the country. However, rock burst disasters are particularly prominent. In order to effectively curb the frequent occurrence of rock burst in local coal mines and provide reference for rock burst prevention and control in areas with similar conditions, the occurrence law of rock burst has been basically clarified by analyzing 24 mines and 85 rock burst cases in Shaanxi coal mines over the past 10 years, and conducted classified prevention and control research based on the main control factors. The research results indicate that coal mine rock burst in Shaanxi Province has the characteristics of concentrated disaster mines, severe disaster severity, significant overlapping effects of multiple disasters, and high difficulty in prevention and control; The monitoring technology and prevention technology of rock burst are almost synchronized with the construction process of local regulations, achieving a late start, high starting point, and demonstration effect;Based on the main controlling factors of rock burst, rock burst in Shaanxi Province is divided into three categories: hard roof dominant type, wide coal pillar dominant type, and geological structure dominant type. In response to the main controlling factors, prevention and control methods for weakening hard roof, transferring high concentrated stress of coal pillar, and releasing structural stress are proposed.Through 10 years of engineering practice, continuous optimization of mine mining design, exploration of new fracturing technologies for drilling areas along the thick and hard roof of coal seams, and increased implementation of anti burst and pressure relief technologies, the occurrence of rock burst has been decreasing year by year, with significant achievements

Quantitative genetics of wing morphology in the parasitoid wasp Nasonia vitripennis : hosts increase sibling similarity

The central aim of evolutionary biology is to understand patterns of genetic variation between species and within populations. To quantify the genetic variation underlying intraspecific differences, estimating quantitative genetic parameters of traits is essential. In Pterygota, wing morphology is an important trait affecting flight ability. Moreover, gregarious parasitoids such as Nasonia vitripennis oviposit multiple eggs in the same host, and siblings thus share a common environment during their development. Here we estimate the genetic parameters of wing morphology in the outbred HVRx population of N. vitripennis, using a sire-dam model adapted to haplodiploids and disentangled additive genetic and host effects. The results show that the wing-size traits have low heritability (h2 ~ 0.1), while most wing-shape traits have roughly twice the heritability compared with wing-size traits. However, the estimates increased to h2 ~ 0.6 for wing-size traits when omitting the host effect from the statistical model, while no meaningful increases were observed for wing-shape traits. Overall, host effects contributed to ~50% of the variation in wing-size traits. This indicates that hosts have a large effect on wing-size traits, about fivefold more than genetics. Moreover, bivariate analyses were conducted to derive the genetic relationships among traits. Overall, we demonstrate the evolutionary potential for morphological traits in the N. vitripennis HVRx-outbred population, and report the host effects on wing morphology. Our findings can contribute to a further dissection of the genetics underlying wing morphology in N. vitripennis, with relevance for gregarious parasitoids and possibly other insects as well.</p