Explore the vast range of titles available.

\"Explains how to use the scientific method to conduct several science experiments about genetics and evolution. Includes ideas for science fair projects\"--Provided by publisher.

Genetics is an important basic course in the field of life science, and the cultivation of students' practical ability should be emphasized in the experimental teaching of genetics. How to let students have more time to participate in the experimental practice within the limited class hours? Our genetics experimental teaching team has developed innovative teaching models on the basis of traditional teaching models. In order to improve students' independent thinking and practical ability and cultivate their interest in scientific research and scientific accomplishment, experimental teaching is carried out through the learning mode of teachers' questions raised before class, students' experimental plans designed before class and students' experimental tasks completed. Through questionnaires distributed after class, this paper investigates students' opinions and suggestions on innovative teaching mode, hoping to give full play to the role of 'innovative teaching mode' in genetics experimental teaching through interaction and continuous improvement between teachers and students, so as to lay a foundation for improving students' comprehensive ability and cultivating innovative talents.

Presents new, tested experiments related to the intriguing field of genetics. The experiments are designed to promote interest in science in and out of the classroom, and to improve critical-thinking skills.

Dual fuel engines constitute a viable solution for enhancing the environmental sustainability of the shipping operations. Although these engines comply with the Tier III NOx emissions regulations when operating at the gas mode, additional measures are required to ensure such compliance at the diesel mode. Hence, this study aimed to optimise the settings of a marine four-stroke dual fuel (DF) engine equipped with exhaust gas recirculation (EGR) and air bypass (ABP) systems by employing simulation and optimisation techniques, so that the engine when operating at the diesel mode complies with the ‘Tier III’ requirements. A previous version of the engine thermodynamic model was extended to accommodate the EGR and ABP systems modelling. Subsequently, a combination of optimisation techniques including multiobjective genetic algorithms (MOGA) and design of experiments (DoE) parametric runs was employed to identify both the engine and the EGR/ABP systems settings with the objective to minimise the engine brake specific fuel consumption and reduce the NOx emissions below the Tier III limit. The derived simulation results were employed to analyse the EGR system involved interactions and their effects on the engine performance and emissions trade-offs. A sensitivity analysis was performed to reveal the interactions between considered engine settings and quantify their impact on the engine performance parameters. The derived results indicate that EGR rates up to 35% are required, so that the investigated engine with EGR and ABP systems, when operating at the diesel mode, achieves compliance with the ‘Tier III’ NOx emissions, whereas the associated engine brake specific fuel consumption penalty is up to 8.7%. This study demonstrates that the combination of EGR and ABP systems can constitute a functional solution for achieving compliance with the stringent regulatory requirements and provides a better understating of the underlined phenomena and interactions of the engine subsystems parameters variations for the investigated engine equipped with EGR and ABP systems.

Comparison of some normal experiments involving intraclass and inter-class correlation is reduced to comparison of one-way random normal experiments. In consequence, the main result in Shaked and Tong is generalized and completed.

Andrew Feinberg, Christine Iacobuzio-Donahue and colleagues describe the epigenomic reprogramming that occurs during pancreatic cancer progression. They also show that hematogenous metastases co-evolve a dependence on the oxidative branch of the pentose phosphate pathway (oxPPP) and that oxPPP inhibition reverses chromatin reprogramming and blocks tumorigenic potential. During the progression of pancreatic ductal adenocarcinoma (PDAC), heterogeneous subclonal populations emerge that drive primary tumor growth, regional spread, distant metastasis, and patient death. However, the genetics of metastases largely reflects that of the primary tumor in untreated patients, and PDAC driver mutations are shared by all subclones. This raises the possibility that an epigenetic process might operate during metastasis. Here we report large-scale reprogramming of chromatin modifications during the natural evolution of distant metastasis. Changes were targeted to thousands of large chromatin domains across the genome that collectively specified malignant traits, including euchromatin and large organized chromatin histone H3 lysine 9 (H3K9)-modified (LOCK) heterochromatin. Remarkably, distant metastases co-evolved a dependence on the oxidative branch of the pentose phosphate pathway (oxPPP), and oxPPP inhibition selectively reversed reprogrammed chromatin, malignant gene expression programs, and tumorigenesis. These findings suggest a model whereby linked metabolic–epigenetic programs are selected for enhanced tumorigenic fitness during the evolution of distant metastasis.

Construction of a series of genomically recoded organisms whose growth is restricted by the expression of essential genes dependent on exogenously supplied synthetic amino acids introduces novel orthogonal barriers between these engineered organisms and the environment, thereby creating safer genetically modified organisms. Two routes to safer GMOs Two manuscripts published in this issue of Nature describe independent approaches towards generating an organism dependent on unnatural amino acids, a development which could find applications for biocontainment and exploration of previously unsampled fitness landscapes. George Church and colleagues redesigned essential enzymes in an organism ( Escherichia coli ) with an altered genetic code to make it metabolically dependent on non-standard amino acids for survival. The resulting genetically modified organisms (GMOs) cannot metabolically circumvent their biocontainment mechanisms and show unprecedented resistance to evolutionary escape. The few escapees are rapidly outcompeted by unmodified organisms. Using multiplex automated genome engineering, Farren Isaacs and colleagues construct a series of genomically recoded organisms whose growth is restricted by the expression of essential genes that depend on exogenously supplied synthetic amino acids. They constructed synthetic auxotrophs with advanced orthogonal barriers between engineered organisms and the environment, thereby creating safer GMOs. Genetically modified organisms (GMOs) are increasingly used in research and industrial systems to produce high-value pharmaceuticals, fuels and chemicals 1 . Genetic isolation and intrinsic biocontainment would provide essential biosafety measures to secure these closed systems and enable safe applications of GMOs in open systems 2 , 3 , which include bioremediation 4 and probiotics 5 . Although safeguards have been designed to control cell growth by essential gene regulation 6 , inducible toxin switches 7 and engineered auxotrophies 8 , these approaches are compromised by cross-feeding of essential metabolites, leaked expression of essential genes, or genetic mutations 9 , 10 . Here we describe the construction of a series of genomically recoded organisms (GROs) 11 whose growth is restricted by the expression of multiple essential genes that depend on exogenously supplied synthetic amino acids (sAAs). We introduced a Methanocaldococcus jannaschii tRNA:aminoacyl-tRNA synthetase pair into the chromosome of a GRO derived from Escherichia coli that lacks all TAG codons and release factor 1, endowing this organism with the orthogonal translational components to convert TAG into a dedicated sense codon for sAAs. Using multiplex automated genome engineering 12 , we introduced in-frame TAG codons into 22 essential genes, linking their expression to the incorporation of synthetic phenylalanine-derived amino acids. Of the 60 sAA-dependent variants isolated, a notable strain harbouring three TAG codons in conserved functional residues 13 of MurG, DnaA and SerS and containing targeted tRNA deletions maintained robust growth and exhibited undetectable escape frequencies upon culturing ∼10 11 cells on solid media for 7 days or in liquid media for 20 days. This is a significant improvement over existing biocontainment approaches 2 , 3 , 6 , 7 , 8 , 9 , 10 . We constructed synthetic auxotrophs dependent on sAAs that were not rescued by cross-feeding in environmental growth assays. These auxotrophic GROs possess alternative genetic codes that impart genetic isolation by impeding horizontal gene transfer 11 and now depend on the use of synthetic biochemical building blocks, advancing orthogonal barriers between engineered organisms and the environment.

Peter Campbell, Mel Greaves and colleagues use exome and whole-genome sequencing to characterize somatic mutations in childhood acute lymphoblastic leukemias with the ETV6 - RUNX1 fusion gene. They find that RAG-mediated deletions are the dominant mutational process. The ETV6 - RUNX1 fusion gene, found in 25% of childhood acute lymphoblastic leukemia (ALL) cases, is acquired in utero but requires additional somatic mutations for overt leukemia. We used exome and low-coverage whole-genome sequencing to characterize secondary events associated with leukemic transformation. RAG-mediated deletions emerge as the dominant mutational process, characterized by recombination signal sequence motifs near breakpoints, incorporation of non-templated sequence at junctions, ∼30-fold enrichment at promoters and enhancers of genes actively transcribed in B cell development and an unexpectedly high ratio of recurrent to non-recurrent structural variants. Single-cell tracking shows that this mechanism is active throughout leukemic evolution, with evidence of localized clustering and reiterated deletions. Integration of data on point mutations and rearrangements identifies ATF7IP and MGA as two new tumor-suppressor genes in ALL. Thus, a remarkably parsimonious mutational process transforms ETV6 - RUNX1 –positive lymphoblasts, targeting the promoters, enhancers and first exons of genes that normally regulate B cell differentiation.

Zebrafish, a popular organism for studying embryonic development and for modeling human diseases, has so far lacked a systematic functional annotation program akin to those in other animal models. To address this, we formed the international DANIO-CODE consortium and created a central repository to store and process zebrafish developmental functional genomic data. Our data coordination center ( https://danio-code.zfin.org ) combines a total of 1,802 sets of unpublished and re-analyzed published genomic data, which we used to improve existing annotations and show its utility in experimental design. We identified over 140,000 cis -regulatory elements throughout development, including classes with distinct features dependent on their activity in time and space. We delineated the distinct distance topology and chromatin features between regulatory elements active during zygotic genome activation and those active during organogenesis. Finally, we matched regulatory elements and epigenomic landscapes between zebrafish and mouse and predicted functional relationships between them beyond sequence similarity, thus extending the utility of zebrafish developmental genomics to mammals. The DANIO-CODE consortium leverages a large-scale multiomic dataset to improve zebrafish genome annotation. They identify ~140,000 cis -regulatory elements throughout development and perform a comparison with the mouse regulatory landscape.