Time to start intervening in the human germline? A utilitarian perspective.

Focusing on present-day possibilities raised by existing technology, I consider the normative aspects of genetically modifying the human germline from a utilitarian standpoint. With reference to a hypothetical case, I examine the probable consequences of permitting a well-conceived attempt to correct a disease-associated gene in the human germline using current CRISPR gene-editing technology. I consider inter alia the likely effects on utility of creating healthy new lives, of discouraging adoption, and of kickstarting a revolution in human germline genetic modification (HGGM). I reject various objections to HGGM, including claims that the risks of genetic harm outweigh the likely benefits. From this utilitarian analysis, I conclude that strong grounds exist to support intervening in the human germline using current technology. Delay in commencing such work will impose a utility cost, because the longer we wait until commencing the HGGM revolution and moving towards a world of increased utility, the greater will be the quantity of suffering accrued meantime through genetically influenced disease. Nevertheless, considering residual safety concerns and the negative publicity engendered by an ethically problematic recent (2018) first attempt at HGGM, it seems prudent-and ultimately generative of the greatest amount of utility-to delay implementing HGGM for a modest period of time, in the order of 1-2 years.

Germline gene editing and the precautionary principle.

The precautionary principle aims to influence decision-making in contexts where some activity poses uncertain but potentially grave threats. This perfectly describes the controversy surrounding germline gene editing. This article considers whether the precautionary principle should influence how we weigh the risks and benefits of human germline interventions, focusing especially on the possible threats to the health of future generations. We distinguish between several existing forms of the precautionary principle, assess their plausibility and consider their implications for the ethics of germline modification. We also offer a novel form of the precautionary principle: the sufficientarian precautionary principle. Some plausible versions of the precautionary principle recommend placing somewhat greater weight on avoiding threats to future generations than on achieving short-term benefits. However, no plausible versions of the precautionary principle entail that we should outright reject the use germline gene editing in human reproduction and some, such as the sufficientarian version, might endorse its use.

Mitochondrial Replacement Techniques: Divergence in Global Policy.

In 2015, the UK became the first country permitting the clinical application of mitochondrial replacement techniques (MRT). Here, we explore how MRT have led to diverging international policy. In response, we recommend focused regulatory efforts coupled with United Nations (UN) leadership to build international consensus on the future of MRT.

"Editing" Genes: A Case Study About How Language Matters in Bioethics.

Metaphors used to describe new technologies mediate public understanding of the innovations. Analyzing the linguistic, rhetorical, and affective aspects of these metaphors opens the range of issues available for bioethical scrutiny and increases public accountability. This article shows how such a multidisciplinary approach can be useful by looking at a set of texts about one issue, the use of a newly developed technique for genetic modification, CRISPRcas9.

Germline Manipulation and Our Future Worlds.

Two genetic technologies capable of making heritable changes to the human genome have revived interest in, and in some quarters a very familiar panic concerning, so-called germline interventions. These technologies are: most recently the use of CRISPR/Cas9 to edit genes in non-viable IVF zygotes and Mitochondrial Replacement Therapy (MRT) the use of which was approved in principle in a landmark vote earlier this year by the United Kingdom Parliament. The possibility of using either of these techniques in humans has encountered the most violent hostility and suspicion. However it is important to be aware that much of this hostility dates back to the fears associated with In Vitro Fertilization (IVF) and other reproductive technologies and by cloning; fears which were baseless at the time concerning both IVF and cloning the use of both of which have proved to be highly beneficial to humanity and which have been effectively regulated and controlled. This paper argues that CRISPR should by pursued through researh until it is safe enough for use in humans but there is no reason to suppose at this stage that such use will be unsafe or unethical (Collins 2015).

Human Germline CRISPR-Cas Modification: Toward a Regulatory Framework.

CRISPR germline editing therapies (CGETs) hold unprecedented potential to eradicate hereditary disorders. However, the prospect of altering the human germline has sparked a debate over the safety, efficacy, and morality of CGETs, triggering a funding moratorium by the NIH. There is an urgent need for practical paths for the evaluation of these capabilities. We propose a model regulatory framework for CGET research, clinical development, and distribution. Our model takes advantage of existing legal and regulatory institutions but adds elevated scrutiny at each stage of CGET development to accommodate the unique technical and ethical challenges posed by germline editing.

Direct modification of spermatogonial stem cells using lentivirus vectors in vivo leads to efficient generation of transgenic rats.

Spermatogonial stem cells (SSCs) transmit genetic information to the next progeny in males. Thus, SSCs are a potential target for germline modifications to generate transgenic animals. In this study, we report a technique for the generation of transgenic rats by in vivo manipulation of SSCs with a high success rate. SSCs in juvenile rats were transduced in vivo with high titers of lentivirus harboring enhanced green fluorescent protein and mated with wild-type females to create founder rats. These founder rats expressed the transgene and passed on the transgene with an overall success rate of 50.0%. Subsequent generations of progeny from the founder rats both expressed and passed on the transgene. Thus, direct modification of SSCs in juvenile rats is an effective means of generating transgenic rats through the male germline. This technology could be adapted to larger animals, in which existing methods for gene modification are inadequate or inapplicable, resulting in the generation of transgenic animals in a variety of species.

Germline Modification and Policymaking: The Relationship between Mitochondrial Replacement and Gene Editing.

'Mitochondrial replacement' and 'germline gene editing' are relatively new techniques that represent a significant moral, technological, and legal threshold, as they would introduce permanent and heritable changes to the human gene pool. This article examines the close relationship between these two technologies over time, considering what regulatory lessons can be learned from the former as attention turns to the latter. It argues that the UK's 'mitochondrial replacement' approval process should not be taken as a model for the wider regulation of germline gene editing, and that policy-making needs to contend with a comprehensive picture of the social and political meaning of these technologies in the world.

Human germline editing: a historical perspective.

The development of the genome editing system called CRISPR-Cas9 has opened a huge debate on the possibility of modifying the human germline. But the types of changes that could and/or ought to be made have not been discussed. To cast some light on this debate, I will describe the story of the CRISPR-Cas9 system. Then, I will briefly review the projects for modification of the human species that were discussed by biologists throughout the twentieth century. Lastly, I will show that for plenty of reasons, both scientific and societal, germline modification is no longer a priority for our societies.

Genome engineering through CRISPR/Cas9 technology in the human germline and pluripotent stem cells.

BACKGROUND: With the recent development of CRISPR (clustered regularly interspaced short palindromic repeats)/Cas9 genome editing technology, the possibility to genetically manipulate the human germline (gametes and embryos) has become a distinct technical possibility. Although many technical challenges still need to be overcome in order to achieve adequate efficiency and precision of the technology in human embryos, the path leading to genome editing has never been simpler, more affordable, and widespread. OBJECTIVE AND RATIONALE: In this narrative review we seek to understand the possible impact of CRISR/Cas9 technology on human reproduction from the technical and ethical point of view, and suggest a course of action for the scientific community. SEARCH METHODS: This non-systematic review was carried out using Medline articles in English, as well as technical documents from the Human Fertilisation and Embryology Authority and reports in the media. The technical possibilities of the CRISPR/Cas9 technology with regard to human reproduction are analysed based on results obtained in model systems such as large animals and laboratory rodents. Further, the possibility of CRISPR/Cas9 use in the context of human reproduction, to modify embryos, germline cells, and pluripotent stem cells is reviewed based on the authors' expert opinion. Finally, the possible uses and consequences of CRISPR/cas9 gene editing in reproduction are analysed from the ethical point of view. OUTCOMES: We identify critical technical and ethical issues that should deter from employing CRISPR/Cas9 based technologies in human reproduction until they are clarified. WIDER IMPLICATIONS: Overcoming the numerous technical limitations currently associated with CRISPR/Cas9 mediated editing of the human germline will depend on intensive research that needs to be transparent and widely disseminated. Rather than a call to a generalized moratorium, or banning, of this type of research, efforts should be placed on establishing an open, international, collaborative and regulated research framework. Equally important, a societal discussion on the risks, benefits, and preferred applications of the new technology, including all relevant stakeholders, is urgently needed and should be promoted, and ultimately guide research priorities in this area.

Germline Modification and Engineering in Avian Species.

Production of genome-edited animals using germline-competent cells and genetic modification tools has provided opportunities for investigation of biological mechanisms in various organisms. The recently reported programmed genome editing technology that can induce gene modification at a target locus in an efficient and precise manner facilitates establishment of animal models. In this regard, the demand for genome-edited avian species, which are some of the most suitable model animals due to their unique embryonic development, has also increased. Furthermore, germline chimera production through long-term culture of chicken primordial germ cells (PGCs) has facilitated research on production of genome-edited chickens. Thus, use of avian germline modification is promising for development of novel avian models for research of disease control and various biological mechanisms. Here, we discuss recent progress in genome modification technology in avian species and its applications and future strategies.

Direct modification of spermatogonial stem cells using lentivirus vectors in vivo leads to efficient generation of transgenic rats / 亚洲男科学杂志(英文版)

Spermatogonial stem cells (SSCs) transmit genetic information to the next progeny in males. Thus, SSCs are a potential target for germline modifications to generate transgenic animals. In this study, we report a technique for the generation of transgenic rats by in vivo manipulation of SSCs with a high success rate. SSCs in juvenile rats were transduced in vivo with high titers of lentivirus harboring enhanced green fluorescent protein and mated with wild-type females to create founder rats. These founder rats expressed the transgene and passed on the transgene with an overall success rate of 50.0%. Subsequent generations of progeny from the founder rats both expressed and passed on the transgene. Thus, direct modification of SSCs in juvenile rats is an effective means of generating transgenic rats through the male germline. This technology could be adapted to larger animals, in which existing methods for gene modification are inadequate or inapplicable, resulting in the generation of transgenic animals in a variety of species.