## GMOs in science and research

Besides the employment of GMOs in biotechnology, genetic modification of various types of organisms is a common part of scientific work. If a scientist is interested in the function of an unknown gene, one possibility is to remove this gene from the organism's genome (using molecular biology methods) and then observe the properties of this organism. If any of the observed characteristics changes, it is possible that the studied gene is involved in the development of this characteristic (if the colouration of the organism was to change, it is likely that the gene of interest is responsible for the standard colouration, etc.). If the scientist has some basic information about the studied gene, they can also use more complicated forms of genetic modification. For example, if the gene encodes a protein whose localisation inside the cell is unknown, this gene can be combined with a gene encoding a green fluorescent protein (originally isolated from the sea jellyfish Aequorea victoria). As a result, the protein product of the studied gene will be labelled with a fluorescent label that can be visualizsed using a fluorescent microscope. Using this approach, it is possible to monitor the movement and location of various proteins in a wide variety of cells (Figure 17.4).

When investigating the properties of a certain protein, another option is to introduce mutations designed by scientists into the gene that encodes this protein. If the activity, localisation, or function of the resulting protein changes, we can conclude that the mutation has affected one of its important parts (not all parts of a protein are equally important, so some mutations have practically no consequences, while others can lead to a complete loss of function, described in detail in chapter 5 – mutations how they arise and what to do with them). In some cases, the genetic modification of a certain organism is not even used as a goal of scientific research, but rather as a tool for examining the genes of different organisms. Thus, scientists can introduce certain genes from one species into another and observe a change in its properties. Depending on how the properties change, it is possible to recognise some of the functions of the studied gene and its role in the organism in which it is naturally found. Due to these types of observations, scientists can understand the functions of individual genes and their mutual relationships.