Genetic modification

DOI: 10.4324/9780415249126-L133-2
Version: v2,  Published online: 2020
Retrieved April 20, 2021, from

1. What is genetic modification?

All biological entities consist of cells. Most cells contain a genetic material known as DNA, which is organised into genes, which in turn sit on chromosomes. Genes direct the production of materials called proteins that allow cells to grow and make the components necessary for survival. Sometimes, an error occurs in these processes, which can be trivial or serious depending on where the error lies and how many cells of the organism it is present in. Additionally, some of the cellular processes that exist in nature may be inefficient. When such errors or inefficiencies exist, the question of whether genetic modification should be used to change or ameliorate them arises. What constitutes a serious or inefficient outcome of gene expression is itself an important philosophical question. It raises issues about welfare, justice, relationships between human persons and the environment, and whether there are any biological norms by which genetic goals might be directed.

At its broadest, genetic modification means altering the complement of genetic material (also known as ‘genetic makeup’) within a cell of an organism. The intent of such an alteration is to augment the function of the cell, or the function of the organism to which the cell belongs. Such changes can include adding, removing, or substituting genetic material. Depending on the technique employed, this change could take place at the level of a DNA base (via recombinant DNA technology, which involves breaking apart and reassembling strands of DNA), via changing a whole chromosome, or by swapping either organelles (so-called mini organs within a cell, such as mitochondria) or an entire nucleus. Genetic modification is a species-neutral term and as such can be used to describe this activity in humans, non-human animals, plants, or microbes.

In philosophy and bioethics, the most common usage of the term genetic modification is to describe a direct and intentional intervention, used with the aim to create a genetically modified organism (GMO). This action can introduce genetic material from the same species, a different species, or novel genetic material not otherwise found in nature. Some have also classed activities such as selective breeding (also known as controlled breeding) or the occurrence of spontaneous (naturally occurring) changes to the genome as being genetic modifications. These have existed for thousands of years. For the purposes of this chapter, genetic modification is taken to mean direct (intentional) interventions, initiated by humans, that change a cell’s genome. That is, genetic modification is taken to mean an action that renders the total genetic complement of a cell different from that prior to the intervention occurring. In recent years, scientific techniques to allow these kinds of direct change have become faster, cheaper, and more accurate. This brings with it novel (or at least more pressing) ethical challenges.

Genetic modification is also related to a number of other terms and is often used synonymously with them. For example, an organism may be said to be ‘genetically engineered’ once genetic modification has taken place. In humans and some non-human animals, the term gene therapy is also often applied to describe a process of genetic modification that is intended to reduce or remove the chance of a genetic condition arising.

Some may distinguish between genetic and genomic modification (e.g. Resnik and Langer 2001). Genetic modification includes changes made at the level of DNA. Genomic modification includes a change made at the level of the genome, but which does not necessarily intervene at the level of DNA. For example, a change made to a human oocyte using gene editing to remove a mutation that will lead to a serious genetic condition developing in the resulting child would be genetic modification; while applying techniques of mitochondrial donation (also known as mitochondrial replacement) to create a new oocyte – intended to prevent the transmission of serious mitochondrial disease – would be genomic modification. For the purposes of this entry, genetic modification denotes both genetic and genomic modifications.

In humans and some non-human animals, another distinction is often drawn between somatic and germline (or inheritable) modifications. A somatic modification is made in a cell where there is no intention that the change will then be present in offspring of the being whose cell is changed. A germline modification is made in reproductive cells (oocytes and sperm cells) and will go on to be inherited by future generations. Traditionally, germline interventions have served as an ethical dividing line (Rasko et al. 2006) between what is permissible and impermissible. However, this distinction is not always clear-cut (Newson and Wrigley 2017), and arguments are emerging that germline changes may be countenanced when certain other considerations are satisfied (Nuffield Council on Bioethics 2018).

While the term genetic modification was once reserved for interventions in non-human animals and plants, it is now also well embedded in discussions of changes to human cells. That said, in certain nascent applications of genetic modification – particularly those for use in humans – there have also been some recent moves away from the use of ‘genetic modification’. For example, more specific terms such as gene editing or mitochondrial donation are now in wide use. This move reflects and distinguishes technological developments but is also perhaps a mechanism to distance certain interventions from other more controversial applications.

Genetic modification is thus a broad term. This general nature can be advantageous, because its scope can encompass many different activities with a common component. However, it can also raise some problems, due to ambiguity or concerns over its pejorative implications – some genetic modification activities may be considered as ethically problematic merely because of an association with another contentious activity.

Citing this article:
Newson, Ainsley J. and Anthony Wrigley. What is genetic modification?. Genetic modification, 2020, doi:10.4324/9780415249126-L133-2. Routledge Encyclopedia of Philosophy, Taylor and Francis,
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