Aeroelasticity has become a critical issue for Multi-Megawatt wind turbine due to the longer and more flexible blade. In this paper, the development of aeroelasticity and aeroelastic codes for wind turbine is reviewed and the aeroelastic models for wind turbine blade are described, based on which, the current research focuses for large scale wind turbine are discussed, including instability problems for onshore and offshore wind turbines, effects of complex inflow, nonlinear effects of large blade deflection, smart structure technologies, and aerohydroelasticity. Finally, the future development of aeroelastic code for large scale wind turbine: aeroservoelasticity and smart rotor control; nonlinear aeroelasticity due to large blade deflection; full-scale 3D computational fluid dynamics (CFD) solution for dynamics; and aerohydroelasticity are presented.
Base editing has the potential to improve important economic traits in agriculture and can precisely convert single nucleotides in DNA or RNA sequences into minimal double-strand DNA breaks (DSB). Adenine base editors (ABE) have recently emerged as a base editing tool for the conversion of targeted A:T to G:C, but have not yet been used in sheep. ABEmax is one of the latest versions of ABE, which consists of a catalytically-impaired nuclease and a laboratory-evolved DNA-adenosine deaminase. The Booroola fecundity (FecB B) mutation (g.A746G, p.Q249R) in the bone morphogenetic protein receptor 1B (BMPR1B) gene influences fecundity in many sheep breeds. In this study, by using ABEmax we successfully obtained lambs with defined point mutations that result in an amino acid substitution (p.Gln249Arg). The efficiency of the defined point mutations was 75% in newborn lambs, since six lambs were heterozygous at the FecB B mutation site (g.A746G, p.Q249R), and two lambs were wild-type. We did not detect off-target mutations in the eight edited lambs. Here, we report the validation of the first gene-edited sheep generated by ABE and highlight its potential to improve economically important traits in livestock.
Background
After domestication, the evolution of phenotypically-varied sheep breeds has generated rich biodiversity. This wide phenotypic variation arises as a result of hidden genomic changes that range from a single nucleotide to several thousands of nucleotides. Thus, it is of interest and significance to reveal and understand the genomic changes underlying the phenotypic variation of sheep breeds in order to drive selection towards economically important traits.
Review
Various traits contribute to the emergence of variation in sheep phenotypic characteristics, including coat color, horns, tail, wool, ears, udder, vertebrae, among others. The genes that determine most of these phenotypic traits have been investigated, which has generated knowledge regarding the genetic determinism of several agriculturally-relevant traits in sheep. In this review, we discuss the genomic knowledge that has emerged in the past few decades regarding the phenotypic traits in sheep, and our ultimate aim is to encourage its practical application in sheep breeding. In addition, in order to expand the current understanding of the sheep genome, we shed light on research gaps that require further investigation.
Conclusions
Although significant research efforts have been conducted in the past few decades, several aspects of the sheep genome remain unexplored. For the full utilization of the current knowledge of the sheep genome, a wide practical application is still required in order to boost sheep productive performance and contribute to the generation of improved sheep breeds. The accumulated knowledge on the sheep genome will help advance and strengthen sheep breeding programs to face future challenges in the sector, such as climate change, global human population growth, and the increasing demand for products of animal origin.
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