Genome, gene and genomics

A genome is the collection of all the DNA in our body, and in every living organism. DNA is in every cell of our body and is the blueprint for how our body develops and functions. It is a chemical structure made from long strings of smaller molecules called nucleotides.

A gene is a small sequence of these nucleotides that performs a particular function. Usually the function of a gene is to synthesise proteins, which help build and maintain the body.

Genomics describes the study of all of a person's genes - the genome. It includes the study of diseases such as heart disease, asthma, diabetes and cancer because these diseases are typically caused more by a combination of genetic and environmental factors than by individual genes. Genomics is offering new possibilities for therapies and treatments for some complex diseases, as well as new diagnostic methods.

Genotype and phenotype

Your genotype is all the genes that you have inherited from your parents. Your phenotype is all the observable traits about you. This could be your physical form (like your weight and height), your physiology, or your behaviour.

Your phenotype is a result of your genes plus environmental conditions. To understand a disease better and how we can treat it, it helps to have both genotypic and phenotypic information about the patient.

Linking the genotype (gene sequence) and phenotype data from the same person makes it possible to study these types of data together.

Personalised medicine

Personalised medicine refers to precise tailoring of a patient's diagnosis and treatment to their specific characteristics, like their age, gender, weight, medical history. This is in contrast to a 'one size fits all' approach to medicine, where each patient is given a standard treatment, and their individual characteristics have less influence on their management and care.

In recent years, personalised medicine has also come to include using a patient's linked genotype and phenotype data to decide the best diagnosis and treatment. If a patient has genes associated with an increased risk of cancer or diabetes, for example, then preventative lifestyle changes can be recommended. Clinicians can also see what genetic mutations are in a patient's cancer, and give treatment targeted to these mutations.

Personalised medicine is also fraught with potential ethical, legal and security issues. For example, not only is a patient's treatment data such as scans and the results of blood samples made available to clinicians,but also their genotype and phenotype data . This is highly sensitive and private data, so great care needs to be taken that the data is stored securely and used ethically and legally.