Environmental Genomics
Glossary of terms
DNA
DNA (deoxyribonucleic acid) is the molecule that carries the genetic information needed to produce an organism and make it work. DNA is a chain composed of four bases (Adenine, Thymine, Guanine and Cytosine). Information is coded depending on the precise sequences of these bases.
Genes
Genes are units of genetic information and are made of DNA. Some contain the instructions for producing proteins, whilst others control and regulate the activities of other genes. Genes determine the inherited characteristics that distinguish one individual from another. Each human has an estimated 30-45 thousand genes.
Genome
This is the complete genetic material of an organism including all the genes as well as additional non-coding DNA.
Genomics
Researchers have identified the entire DNA sequence of a growing number of species, and we are developing ever greater insight into how the genome functions to give rise to a complete organism. This new capacity has created the field of genomics and has revolutionised biological investigation. Genomics offers new opportunities for investigation into how the genome interacts with the environment. For example:
- researchers can identify how tens of thousands of genes respond, at any one time, to environmental change. Until recently, they could only study one gene at a time.
- scientists can say how one species is related to another on a genetic level, markedly increasing our knowledge of evolution.
Environmental genomics
The specific field of environmental genomics answers questions such as:
- which genes are important for survival and reproduction?
- how do plants, animals and microbes respond to abrupt or temporary changes, for example, seasonal temperatures or changing salt concentrations in tidal estuaries?
- why do some pollutants interfere with sexual development in fish populations?
- how did the genome evolve?
Glossary of genomic technologies
DNA sequencing
This system allows researchers to evaluate variation in DNA sequences among genes from different individuals. It also allows scientists to easily isolate and characterise different genes. Once a highly complex process, DNA sequencing is now done regularly in many laboratories using automated methods.
Genetic Markers
These are easily identified short sequences of DNA which can be used to keep track of an individual, a tissue, a cell, a nucleus, a chromosome, or a gene.
Polymerase chain reaction (PCR)
PCR involves taking a sample of DNA and placing it in a reaction mixture with the enzymes and raw chemicals needed for DNA replication. The mixture is then run through a series of repeated replication cycles to generate multiple copies of the DNA. It is likely that every single project involved in this programme used this technique at some point.
Quantitative PCR (qPCR)
This is a relatively recent advance that extends basic PCR. It enables scientists to know how much DNA has been copied, which in turn enables them to quantify the level of gene expression (the number of copies of DNA (or RNA) in a sample can be related to the activity of the genes).
Quantitative trait loci (QTL) analysis
QTL analysis allows us to simultaneously examine large numbers of genetic markers. These can be used to generate a genetic map for almost any organism. By extending these mapping exercises across large numbers of organisms, scientists can statistically determine regions on the genetic map that influence quantifiable traits, such as body size.
Microarray analysis
This is a powerful new tool that enables scientists to simultaneously evaluate the expressions of thousands of genes. The technique was introduced only shortly before the inception of the Environmental Genomics programme, and enthusiasm over the ability to examine impacts of varying environmental conditions on entire suites of genes was a major motivation for many of the projects funded under this initiative.
Bioinformatics
Bioinformatics is the term applied to the use of sophisticated computational tools to investigate large amounts of data. Statistical, computational, and data handling methods are key components of environmental genomics research.