Genetic Testing Technologies
Learn about sequencing and other technologies used in genetic testing.
Genetic testing is any process that investigates the genome of an individual. As genetic testing has become increasingly common for research, clinical, and general interest purposes, it is now more important than ever to understand the methods used to generate these data. Different genetic tests such as karyotyping, microarrays, and sequencing can be used to examine genetic material at different levels of resolution.
The Human Genome Project was launched in 1990 with the goal of sequencing the entire human genome for the first time. This was an international collaborative project that took 13 years to complete, and the results were an enormous breakthrough for the field of genetics. Since then, sequencing technologies have evolved to become cheaper, faster, and generally more suitable for routine use. In fact, whole genome sequencing can now be completed within a single day at a relatively low cost. The increased availability of different types of genetic tests has expanded their use to the general public—many people have now taken the opportunity to use genetic testing to learn more about their ancestry and risk of various health conditions, and even the pedigrees of their pets.
In this curated selection of videos and interactive materials from the HMX Pro course on Genetic Testing and Sequencing Technologies, you’ll learn about some of the different methods used for genetic sequencing.
Please note: HMX online courses are primarily designed for those working in areas related to healthcare and genetics, including diagnostics and treatments. Given the increasing prevalence of genetic testing technologies, we’ve decided to make relevant material available to all. We understand that not everyone may have the appropriate background, and we encourage you to use other resources as needed to understand any unfamiliar terms and get the most from this material.
Topics
The Different Types and Applications of Genetic Testing
Genetic testing has a wide variety of applications, depending on the approach used. The video below provides an overview of these tools, featuring the Genetic Testing and Sequencing Technologies course instructor Dr. Caity Anderson of Harvard Medical School.
Genetic Sequencing Technologies
Genetic sequencing is a type of genetic testing that determines the sequence of individual DNA base pairs. In the video below, Dr. Christine DeGennaro presents a summary of the different sequencing approaches.
Polymerase Chain Reaction
Polymerase chain reaction (PCR) is a molecular technique used to generate many copies of a region of DNA that is of interest. This is particularly important for sequencing applications, which often require very large quantities of DNA. The following video shows how PCR can be used by scientists to amplify one specific region of DNA.
Sanger Sequencing
One of the first sequencing techniques to be used routinely was Sanger sequencing, which emerged in the 1970s and remained the most widely-used sequencing technique for over 30 years. While it has since been largely superseded by faster, more modern technologies, Sanger sequencing is still considered to be the most accurate sequencing technique. As such, it is often used for sequencing single genes or small regions of DNA, and for validating data generated by other sequencing methods. The following video shows you how it works.
Next Generation Sequencing
Next generation sequencing (NGS) is a term that refers to a collection of sequencing technologies developed after Sanger sequencing (making them the “next generation”). While Sanger sequencing is only able to sequence a single DNA fragment at a time, NGS is capable of massively parallel sequencing, which sequences millions of fragments at once. Although these technologies are considered somewhat less accurate than Sanger sequencing, the increased speed and capacity of NGS technologies have paved the way for routine use of sequencing in medicine and research. The video below shows how NGS works; it is split into sections to aid navigation should you wish to revisit any particular part.
Variant Identification and Classification
NGS produces millions of reads, each of which must be mapped to the corresponding region of the human genome. The accuracy of read mapping and variant identification depends on a variety of factors, including the depth of read coverage and the program used for analysis. The video below provides an outline of the process of variant identification and classification, as well as some of the parameters that must be considered when interpreting NGS sequencing data.
Looking for a more in-depth online learning experience? Our foundational genetics course covers key concepts in the field. If you’d like to learn more about genetic testing and the most recent sequencing technologies and their applications, consider our advanced course on genetic testing and sequencing technologies.