Genetic Engineering Of Animals Research Articles

Social acceptance of genetic engineering technology.

Genetic engineering of animals has been proposed to address societal problems, but public acceptance of the use of this technology is unclear. Previous work has shown that the source of information proposing the technology (e.g. companies, universities), the term used to describe the technology (e.g. genome editing, genetic modification), and the genetic engineering application (e.g. different food products) affects technology acceptance. We conducted three mixed-method surveys and used a causal trust-acceptability model to understand social acceptance of genetic engineering (GE) by investigating 1) the source of information proposing the technology, 2) the term used to describe the technology, and 3) the GE application for farm animals proposed. Further, participants expressed their understanding of technology using a range of terms interchangeably, all describing technology used to change an organism's DNA. We used structural equation modelling and confirmed model fit for each survey. In each survey, perceptions of benefit had the greatest effect on acceptance. Following our hypothesized model, social trust had an indirect influence on acceptance through similar effects of perceived benefit and perceived risk. Additional quantitative analysis showed that the source of information and technology term had little to no effect on acceptance. Applications involving animals were perceived as less beneficial than a plant application, and an application for increased cattle muscle growth was perceived as more risky than a plant application. When assessing the acceptability of applications participants considered impacts on plants, animals, and people, trust in actors and technologies, and weighed benefits and drawbacks of GE. Future work should consider how to best measure acceptability of GE for animals, consider contextual factors and consider the use of inductive frameworks.

Recovery in Function in Olfactory Escheating Cell Transplanted Rat Spinal Cord After Stopping the Injection of Cyclosporine

The study aimed to check whether animals can retain directed forepaw reaching (DFR) function after stopping cyclosporine which is used to prevent immunorejection in xenotransplant of Olfactory Encheating cells (OECs) in Albino Swiss Strain (AS) rat corticospinal tract lesion. The Hematoxylin & Eosin (H&E) staining and immunohistochemistry techniques have been performed on the cryostat sections of corticospinal tract (CST) lesion post-surgery to check the immunorejection and the existence of OEC transplanted tissue before and after injection of cyclosporine. The DFR function have been checked after each stage to see whether animals retain the DFR tasks after stopping cyclosporine . The results show that the daily injection of 100ml diluted cyclosporine avoids immune attack and reduces inflammatory cells infiltrate in delayed CST ipsilateral rat model and also our study proved that stop of cyclosporine injection would not prevent DFR function and the regenerated fibres can still be visualised after 6 months post-operation period.Despite the fact that so many methods such as animal genetic engineering is used to avoid imminuregection after xenotrasplantation in animal model, daily cyclosporine injection for some period after surgery seems to be effective and effortless method to not only deter immunorejection in host animal but it also preserve function such as DFR for a long period post-surgery

Enhancing Animal Disease Resistance, Production Efficiency, and Welfare through Precise Genome Editing.

The major goal of animal breeding is the genetic enhancement of economic traits. The CRISPR/Cas system, which includes nuclease-mediated and base editor mediated genome editing tools, provides an unprecedented approach to modify the mammalian genome. Thus, farm animal genetic engineering and genetic manipulation have been fundamentally revolutionized. Agricultural animals with traits of interest can be obtained in just one generation (and without long time selection). Here, we reviewed the advancements of the CRISPR (Clustered regularly interspaced short palindromic repeats)/Cas (CRISPR associated proteins) genome editing tools and their applications in animal breeding, especially in improving disease resistance, production performance, and animal welfare. Additionally, we covered the regulations on genome-edited animals (GEAs) and ways to accelerate their use. Recommendations for how to produce GEAs were also discussed. Despite the current challenges, we believe that genome editing breeding and GEAs will be available in the near future.

Genetic Engineering in the Twenty-First Century: Genetically modified organisms

In agriculture, animals and plants are engineered to produce pharmaceuticals, and crops are modified to be nutritious, tolerant of herbicides and the natural environment, and resistant to disease. While these goals may seem practical, is it wise to modify plant systems without a clear idea of the long-term effects of genetic engineering in animals and humans? [1].

Rat Model of Intra-articular Chondrocyte Xenotransplantation.

Current treatment options are not providing an adequate solution for cartilage defects. Articular cartilage lesions in particular are not able to repair spontaneously and progressively degenerate with an arthrosic pattern. Aiming to solve this pressing medical need, xenotransplantation of porcine chondrocytes could be developed as a new therapeutic approach. Xenotransplantation is gaining much attention, thanks to the advances in animal genetic engineering and progress in the characterization of the rejection mechanisms that prevent long-term graft survival. In this regard, our team has identified various targets for intervention that should be tested in a meaningful animal model to prove their relevance in rejection of xenogeneic cartilage. To this end, we have recently established a discordant xenotransplantation model by injecting three million porcine articular chondrocytes (PAC) into the femorotibial joint of Lewis rats. This chapter describes this new model, which can be used to assess the immunoregulatory effect of a variety of strategies designed to inhibit rejection of xenogeneic PAC both at the humoral and cellular levels.

Gene editing in livestock: promise, prospects and policy.

Abstract Although genetically engineered livestock were first introduced in the 1980s, only three biomedical applications (ATryn®, Ruconest®, Kanuma®) and one food animal application (AquAdvantage® salmon) have been brought to market. The initial promise of this technology was hampered by low efficiency, random site integration, public resistance and regulatory hurdles. Gene editing has made it possible to precisely target changes in livestock genomes, overcoming previous challenges. Livestock and poultry editing applications include disease resistance, animal welfare, production traits, animals as bioreactors, xenotransplantation and the development of models for human diseases. The extent to which any of these applications are utilized beyond research laboratories will depend upon regulatory frameworks, uptake by livestock producers and industry, and public acceptance. The 2017 draft US Food and Drug Administration regulatory guidance for gene edited animals, which proposes to regulate 'intentional' genomic alterations introduced by editing as new animal drugs irrespective of product novelty or risk, is at odds with emerging regulations around gene edited plants. Lengthy process-based regulation triggered by human 'intention' rather than novel product risk may dissuade animal genetics companies and breeders from employing gene editing to introduce beneficial genetic alterations into livestock populations, effectively the same fate encountered by genetic engineering in animals. Goal conflicts will likely continue between genetic innovations to address problems like animal disease and welfare and concerns around the use of modern molecular genetics in food animals. The early applications that successfully navigate regulatory hurdles will influence the public discussion around gene edited animals and impact the trajectory of future applications.

The Genetic Engineering of Animals and Plants and the Boundaries of Stewardship

Genetic engineering can change the biology of a plant or animal by altering its genome. Historically, selective breeding, induced mutation, and screening have been used to adapt animals and plants for human uses. The advent of specific, more accurate gene editing systems, coupled with cellular and embryological systems for selecting genetically engineered organisms, provides even greater possibilities for altering animals and plants to meet human needs but necessitates an analysis of when and how such tools should be used. Bioethical questions concerning the reasonableness of a genetic experiment, the well-being of the modified organism, the integrity of a species and the environment, and the potential benefit to humans should be addressed before any genetic manipulations are undertaken. Animals and plants can be genetically engineered ethically, but certain lines should not be crossed if we are to be good stewards.

Stakeholder Views on the Creation and Use of Genetically-Engineered Animals in Research

This interview-based study examined the diversity of views relating to the creation and use of genetically-engineered (GE) animals in biomedical science. Twenty Canadian participants (eight researchers, five research technicians and seven members of the public) took part in the interviews, in which four main themes were discussed: a) how participants felt about the genetic engineering of animals as a practice; b) governance of the creation and use of GE animals in research, and whether current guidelines are sufficient; c) the Three Rs (Replacement, Reduction, Refinement) and how they are applied during the creation and use of GE animals in research; and d) whether public opinion should play a greater role in the creation and use of GE animals. Most of the participants felt that the creation and use of GE animals for biomedical research purposes (as opposed to food purposes) is acceptable, provided that tangible human health benefits are gained. However, obstacles to Three Rs implementation were identified, and the participants agreed that more effort should be placed on engaging the public on the use of GE animals in research.

Mammalian interspecies substitution of immune modulatory alleles by genome editing.

We describe a fundamentally novel feat of animal genetic engineering: the precise and efficient substitution of an agronomic haplotype into a domesticated species. Zinc finger nuclease in-embryo editing of the RELA locus generated live born domestic pigs with the warthog RELA orthologue, associated with resilience to African Swine Fever. The ability to efficiently achieve interspecies allele introgression in one generation opens unprecedented opportunities for agriculture and basic research.

An improved Tet-on system to tightly conditionally regulate reporter gene expression

Reporter genes are often used as markers to track the integration and expression of target genes in animal genetic engineering. To avoid potential side effects from reporter genes, in this study an improved Tet-on system was developed to control reporter gene expression, and its effectiveness was explored in transgenic cells. First, the rtTA protein was fused with Tat and NLS proteins to obtain the prokaryotic expression vector pET32a-Tat-rtTA-NSL. A eukaryotic transgenic vector was constructed, p-HS4-BPA-TmA-HS4, in which the reporter (mCherry) and target (PRL) genes were promoted by TRE and BCN, respectively. After confirming the functionality of the transgenic vector, purified rtTA protein and Dox were added to induce expression of the mCherry gene. The optimal amount of purified rtTA protein, its influence on target gene expression, and the time of rtTA protein action were each investigated separately. The results showed that rtTA protein was expressed in transformed E. coli with IPTG induction. TRE could promote mCherry gene expression by co-transfecting the constructed transgenic vector and prtTA plasmid. When purified rtTA protein and Dox were added, red fluorescence was observed in Bcap-37 cells transfected with the p-HS4-BPA-TmA-HS4 vector, and the exogenous PRL gene was expressed regardless of mCherry gene expression. The optimal amount of rtTA protein was 16 μg/mL, and it needed about 6 h to promote mCherry gene expression in transfected cells. These results demonstrate that the expression of the mCherry reporter gene can be tightly and conditionally regulated by our Tet-on system.

Ethical Issues in Behavioral Neuroscience : Ethics of Human Research in Behavioral Neuroscience: Overview of Section II.

Section I. Experimental Animal Research.- Ethical Issues Associated with the Use of Animal Experimentation in Behavioural Neuroscience Research.- The use of animal models in behavioural neuroscience research.- Does the goal justify the methods? Harm and Benefit in Neuroscience Research Using Animals.- A Framework for investigating animal consciousness.- Telos, Conservation of Welfare, and Ethical Issues in Genetic Engineering of Animals.- Would the elimination of the capacity to suffer evolve ethical dilemmas in experimental animal research?.- Section II. Clinical Research.- Ethics of human research in behavioral neuroscience: Overview of section II.- What's special about the ethical challenges of studying disorders with altered brain activity?.- Effects of brain injury on moral agency: Ethical dilemmas in investigating human behavior.- Genetic testing and neuroimaging for youth at risk for mental illness: Trading off benefit and risk.- Externalization of consciousness: Scientific possibilities and clinical implications.- How does enhancing cognition affect human values? How does this translate into social responsibility?.- Deep brain stimulation: A principled and pragmatic approach to understanding the ethical and clinical challenges of an evolving technology.- Ethical issues and ethical therapy associated with anxiety disorders.- Just like a circus: The public consumption of sex differences.- Money and morals: Ending clinical trials for financial reasons.

Role of stem cells in large animal genetic engineering in the TALENs–CRISPR era

The establishment of embryonic stem cells (ESCs) and gene targeting technologies in mice has revolutionised the field of genetics. The relative ease with which genes can be knocked out, and exogenous sequences introduced, has allowed the mouse to become the prime model for deciphering the genetic code. Not surprisingly, the lack of authentic ESCs has hampered the livestock genetics field and has forced animal scientists into adapting alternative technologies for genetic engineering. The recent discovery of the creation of induced pluripotent stem cells (iPSCs) by upregulation of a handful of reprogramming genes has offered renewed enthusiasm to animal geneticists. However, much like ESCs, establishing authentic iPSCs from the domestic animals is still beset with problems, including (but not limited to) the persistent expression of reprogramming genes and the lack of proven potential for differentiation into target cell types both in vitro and in vivo. Site-specific nucleases comprised of zinc finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs) and clustered regulated interspaced short palindromic repeats (CRISPRs) emerged as powerful genetic tools for precisely editing the genome, usurping the need for ESC-based genetic modifications even in the mouse. In this article, in the aftermath of these powerful genome editing technologies, the role of pluripotent stem cells in livestock genetics is discussed.

The Use of Genetically-engineered Animals in Science: Perspectives of Canadian Animal Care Committee Members

The genetic engineering of animals for their use in science challenges the implementation of refinement and reduction in several areas, including the invasiveness of the procedures involved, unanticipated welfare concerns, and the numbers of animals required. Additionally, the creation of genetically-engineered animals raises problems with the Canadian system of reporting animal numbers per Category of Invasiveness, as well as raising issues of whether ethical limits can, or should, be placed on genetic engineering. A workshop was held with the aim of bringing together Canadian animal care committee members to discuss these issues, to reflect on progress that has been made in addressing them, and to propose ways of overcoming any challenges. Although previous literature has made recommendations with regard to refinement and reduction when creating new genetically-engineered animals, the perception of the workshop participants was that some key opportunities are being missed. The participants identified the main roadblocks to the implementation of refinement and reduction alternatives as confidentiality, cost and competition. If the scientific community is to make progress concerning the implementation of refinement and reduction, particularly in the creation and use of genetically-engineered animals, addressing these roadblocks needs to be a priority.

Welfare applications of genetically engineered animals for use in agriculture1

The application of genetic engineering to food animals is often viewed as a means to further increase animal productivity without regard for the welfare of the resulting animals. We offer the perspective that, on the contrary, genetic engineering can, and is, being used to improve animal welfare in modern production systems. Several examples are cited from the current work in the field of animal genetic engineering that should be included in the debate over whether genetically engineered animals should be used in production agriculture. The current debate has slowed the advancement of this technology, which could play a key role in improving animal welfare and sustainability, without considering the potential benefits.

A New Positive/Negative Selection Scheme for Precise BAC Recombineering

Recombineering technology allows the modification of large DNA constructs without using restriction enzymes, enabling the use of bacterial artificial chromosomes (BACs) in genetic engineering of animals and plants as well as in the studies of structures and functions of chromosomal elements in DNA replication and transcription. Here, we report a new selection scheme of BAC recombineering. A dual kanamycin and streptomycin selection marker was constructed using the kanamycin resistance gene and bacterial rpsL (+) gene. Recombination cassettes generated using this dual marker was used to make precise modifications in BAC constructs in a two-step procedure without leaving behind any unwanted sequences. The dual marker was first inserted into the site of modifications by positive selection of kanamycin resistance. In the second step, the counter-selection of streptomycin sensitivity resulted in the replacement of the dual marker with intended modified sequences. This method of BAC modification worked as efficiently as the previously reported galK method and provided a faster and more cost-effective alternative to the galK method.

Intrinsic Value and the Genetic Engineering of Animals

The concept of intrinsic value is often invoked to articulate objections to the genetic engineering of animals, particularly those objections that are not directed at the negative effects the technique might have on the health and welfare of the modified animals. However, this concept was not developed in the context of genetic engineering. Given this external origin, this paper critically examines the assumption that the concept of intrinsic value is suitable to articulate and justify moral objections more specifically directed at the genetic engineering of animals. I discuss four different theories of intrinsic value, two of which defend a moral concept of intrinsic value and two a non-moral one. I conclude that only a particular non-moral concept of intrinsic value is suitable to express specific objections to genetic engineering, because these objections can only be defended in the form of indirect duties regarding animals.

Würde oder Integrität - Verlangt die gentechnische Veränderung von Tieren neue tierethische Konzepte?

Animal genetic engineering seems to point at a normative gap beyond pathocentric welfare theories in animal ethics. Recently developed approaches aim to bridge this gap by means of new normative criteria such as animal dignity and animal integrity. The following comparison of dignity and integrity in the context of animal ethics shows that the dignity concept faces serious problems because of its necessarily anthroporelational character and the different functions of contingent and inherent dignity within ethical reasoning. Unlike animal dignity the concept of animal integrity could prove to be a useful enhancement for pathocentric approaches.

Genetic Engineering and the Integrity of Animals

Genetic engineering evokes a number of objections that are not directed at the negative effects the technique might have on the health and welfare of the modified animals. The concept of animal integrity is often invoked to articulate these kind of objections. Moreover, in reaction to the advent of genetic engineering, the concept has been extended from the level of the individual animal to the level of the genome and of the species. However, the concept of animal integrity was not developed in the context of genetic engineering. Given this external origin, the aim of this paper is to critically examine the assumption that the concept of integrity, including its extensions to the level of the genome and the species, is suitable to articulate and justify moral objections more specifically directed at the genetic engineering of animals.

‘Ethical concepts regarding the genetic engineering of laboratory animals’

Intrinsic value and animal integrity are two key concepts in the debate on the ethics of the genetic engineering of laboratory animals. These concepts have, on the one hand, a theoretical origin and are, on the other hand, based on the moral beliefs of people not directly involved in the genetic modification of animals. This 'external' origin raises the question whether these concepts need to be adjusted or extended when confronted with the moral experiences and opinions of people directly involved in the creation or use of transgenic laboratory animals. To answer this question, 35 persons from the practice of biomedical research who are directly involved in genetic engineering (scientists, biotechnicians, animal caretakers and laboratory animal scientists) were interviewed. They were asked to give their moral opinion on different aspects of the genetic engineering of animals and to react to statements about the concepts of intrinsic value and animal integrity. Analysis of the interviews showed that, contrary to what is often assumed, the respondents embraced these concepts, even those senses that (more) specifically apply to genetic engineering. And although the respondents raised some objections that go beyond issues of animal welfare, these objections could quite well be expressed in terms of the concepts of intrinsic value and animal integrity. In short, the results of the present study strongly suggest that these concepts do not have to be adjusted or extended in the light of the moral experiences and opinions from practice.

Current status of animal-to-human transplantation

The transplantation of animal organs into humans as a way of treating organ failure has been pursued for 100 years. Clinical xenotransplantation, as such, has always failed because the transplanted organ is rejected by the recipient. Recent advances in transplant immunology have revealed some mechanisms underlying the rejection of xenografts, and these discoveries have sparked efforts to use genetic engineering of animals and therapeutics directed at the recipient to overcome this problem. This paper reviews the current understanding of the mechanisms of xenograft rejection and efforts to overcome rejection and other hurdles.