A gene cluster is a group of closely related genes that all code for the same function, or variations on the same function. The study of gene clusters is important for the understanding of evolution and various divergences within the same species, such as different races and ethnicities in humans. Researchers can use statistical analysis to identify such clusters and determine their genetic significance.
Clustering starts with a process known as duplication, where an organism accidentally inherits two copies of the same gene as a result of an error during DNA replication. Duplicated genes may die out, or be passed on to descendents. Over time, they start to spread through the population, until many organisms have the duplication. The genes code for identical proteins and essentially duplicate their intended function.
With each passage of the duplicate genes, the risk that the duplicates will start to diverge increases. Over time, the duplicates become two closely related genes. No longer identical, they code for different proteins that may perform slightly different functions. This can be seen with the globins in humans, a gene cluster of closely related, but still distinct, genes. The more generations pass, the more divergence in gene clusters can be observed.
Tracing gene clusters can allow a researcher to learn more about the evolutionary history of an organism. The researcher can use this information to determine the age of the duplication and how many generations have passed since then. Researchers note that this clustering activity appears to be more common with some types of organisms than others. Insects, for example, have few gene clusters, while animals may have many.
When the same gene cluster shows up in two organisms, it can demonstrate how closely related they are. The divergence may illustrate when two species split, or could allow researchers to track migration patterns. People of Jewish descent, for instance, have some distinct variations in common gene clusters that set them apart from people of other ethnic heritage. When a gene cluster leaps, as will sometimes happen through horizontal gene transfer in organisms like bacteria, it can also provide more information about the origins and history of an organism.
Statistical analysis of sampling data can identify gene clusters as well as families, larger groups of related genes. This must be done carefully to avoid the creation of a false correlation that might lead to incorrect data or conclusions. When researchers report on clusters, they discuss the methodology used in their research and the results so readers can determine the authenticity of the gene cluster study conclusion for themselves.
