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Genomics FAQs

The PCGL Training Team and Patient Partnership Team have prepared some frequently asked questions (FAQs) about genomic research. For FAQs specifically about PCGL, please visit the PCGL FAQ page.

What is genomics?​

Genomics is a type of biology in which researchers study genetic material. An organism's genetic material is called its genome.

Human genomes are made of DNA (deoxyribonucleic acid). DNA is made of two long chains of chemical bases called nucleotides. There are four kinds of chemical bases in DNA, represented by the letters “A”, “C”, “G”, and “T”. The sequence of these bases in our DNA encodes the information that our cells use to make proteins, which make up our bodies.

Between people, most of our genome sequences are the same – around 99.9%! The small differences in our genomes are what give people different traits.

How do we obtain genomic information?​

First, a healthcare provider informs a person about the genomic test. The person gives their consent to have the genomic test. Next, a sample is collected. These samples may be blood, tissue, saliva, or others, depending on the reason for studying the genome. Then, DNA is extracted from the sample. The quality of the DNA is checked, and it is prepared for sequencing.

Sequencing DNA produces a huge amount of data. This data is processed by scientists who use computers and software.

  1. First, they check the quality of the data. They keep only letters (“A”, “C”, “G”, and “T”) they are sure the machine read correctly.
  2. The data is out of order, in many short pieces. The next step is to organize the data into longer genome sequences. The scientists will check that these sequences are complete enough to be used.
  3. The sequence data is then ready to be analyzed.

What does genomic information tell us? What are variants and mutations?​

Genomic tests give us information about the differences between individuals’ genomes. These differences are called variants. Most variants are inherited from our parents, but others, called mutations, occur during our lifetime.

Variants and mutations can be linked with health conditions or diseases. However, not all variants or mutations are harmful. Some result in no changes in our physical traits. Others are responsible for trait differences like eye colour. The effect of a variant or mutation depends on where it is.

A gene is a specific part of the genome that a protein is made from. Proteins serve different functions to make up our bodies. The effect of a variant or mutation in a gene will depend on which gene is affected and where it occurs.

How is genomic testing different from genetic testing?​

Both genetic and genomic tests are used to check a person’s DNA. However, these tests provide different kinds of information.

  • Genetic tests inform your doctor of differences in a small number of specific genes. Genetic tests are often used to check if a person has inherited a specific variant from their parents.
  • Genomic tests provide your doctor with information about many genes. Depending on the kind of genomic test, this can mean all of the genes in the genome. Some genomic tests also provide data from parts of the genome that are not genes but have other functions, like controlling the amount of protein made from nearby genes.

Because many more genes are tested, genomic testing creates much more data than genetic testing.

Sometimes these terms are used interchangeably, because they both provide information about a person’s DNA.

How is genomic information used in healthcare?​

Genomic information can be used to diagnose health conditions. Genomic information can also help your doctor decide how to prevent or treat a disease.

For example, cancer cells often have many changes in their DNA. These changes cause them to behave differently from normal cells. Doctors may order genomic tests to detect these changes. These tests help them decide which treatment is most likely to work on the cancer cells. To learn more about personalized treatment of cancer, visit Cancer Research UK.

How do we learn about genetic variants and mutations?​

We learn about genetic variants and mutations through clinical research studies that use genomic tests. These studies collect health information and samples from many participants. Sequencing DNA from these samples creates genomic data. Researchers then use genomic data and health data to answer research questions. For example: how likely is this genetic variant to cause a health condition? Which treatment will help a cancer patient with a specific tumour mutation?

How do patients join genomic research studies?​

Patients are often referred to genomic research studies by their doctor or genetic counselor. Patient advocacy groups may be aware of relevant research studies. Some patients join research studies by contacting the researchers who are conducting a study.

Patient registries and online databases of clinical trials can also help patients find research studies. Some examples of these are below. These resources are about clinical trials, and are not limited to genomic research.

Where can I learn more about genomics?​

PCGL has a Training Catalog for research participants and members of the public. The catalog includes webpages, documents, videos, and more, on genomics and other topics related to the Library.

References​