Genotyping is one of the most potent tools at a biologist’s disposal. It allows them to look at the set of genes that an individual possesses, which is called their genotype, and compare it to that of others. This has a variety of medical uses, from determining an individual’s parentage to searching for genetic diseases. These uses, along with many upcoming developments, are turning biotechnology and genetics into growth industries that have the potential to revolutionize the world. As such, everyone should familiarize themselves with genotyping.
1. You Don’t Need The Whole Genome
The human genome is extraordinarily large, with billions of DNA base pairs over 23 pairs of chromosomes. It is technically possible for a researchers to sequence every gene in an individual’s genome, but doing so is both expensive and time-consuming. It is also pointless in the vast majority of cases, both because not every base pair provides useful information and because most people only need to look at a relatively small number of genes in order to get the information that they need. Ignoring the irrelevant parts of the genome is a way to save a great deal of time and money.
For example, individuals who want to estimate their risk of developing a certain disease will often have researchers look at the genes that have a known link to that disease while ignoring all others. In the case of paternity tests, the researcher will only examine a handful of regions that are likely to vary based on parentage, while ignoring those that are usually similar within a population. These areas can be as small as a single nucleotide in the sequence, so a test of this kind can be surprisingly quick and easy for a skilled researcher to perform. Full analysis of the genome is reserved for people who want to get the entire picture of their susceptibility to diseases and potential hereditary problems.
2. There Are Many Methods
People often think of genotyping as a single technique, but that is not the case. The term itself refers to any method that will allow the analysis of an individual’s genes. “Most of the modern methods involve attaching a set of highly-visible molecular markers to a gene sequence,” said Transnetyx, Inc. Each marker will only attach to a single type of nucleic acid, so researchers can look at those markers to determine the sequence.
The problem with this method is that it is difficult to do it with large sequences, since the markers are hard to differentiate in large quantities. To deal with that problem, many methods rely on looking at a large group of small fragments, and then looking at the places where they overlap or where specific markers have been attached to reconstruct the sequence as a whole. Naturally, that requires quite a bit of DNA, so researchers usually take a sample from the subject, force it to replicate, and then break it up into smaller sections for analysis. There are quite a few ways to apply these broad strategies, which is where the many different methods of analysis appear.
3. Computers Make It Practical
The greatest downside to that method of analyzing DNA is the amount of work that it takes to reconstruct the sequence. It is possible to do so by hand, and the earliest researchers did exactly that, but the process was excruciatingly slow. If researchers still relied on that type of analysis and other primitive methods, private genotyping would be impossible for all but the wealthiest people. Fortunately, those methods have long since fallen into obsolescence.
Modern methods benefit from both an increased knowledge of the genome and the chemistry that allows it to function, and from increases in computer technology. The newer techniques can do in a few hours what would have taken days to do with older technologies. That change is largely responsible for reducing the price of genotyping to the point where individuals can afford to purchase it. Since genetics is a young field and scientists still have a great deal to learn about it, the techniques are still improving. As they become cheaper and more accurate, more and more people are choosing to learn about their genome, and this trend is likely to continue long into the future.