What is Homology?
Homology is described as similarity in structure between two different taxa. On a genetic level, it means that species contain the same or similar DNA sequence, genes and proteins. Structures as well as proteins are thought to have the same or similar functions across a variety of species. This similarity is typically thought to exist because of a shared common ancestor. While homologs are defined as very similar to each other, it is important to note that this does not mean that they are exactly the same or allow for the same function to be carried out in the body.
Homologs are able to be broken down further into two more categories: paralogs and orthologs. These groupies are based on how emerged from the original species, or common ancestor. Gene duplication in paralogs can change the function depending on the species in question, while orthologs and their function remain the same and are caused by speciation events. The history and relationships of these are often visualized by utilizing phylogenetic trees.
Homology is useful when looking at the relatedness of some species. In order to accurately understand how particular genes function in the human body, we must find animals that have the same or similar genes. Because testing is not allowed on humans, identifying and obtaining model organisms is vital for researching a gene or genetic disease. In the case of MSTN, it is very well conserved across species, with the exception of monkey, zebra fish and fruit fly, while all others have upwards of 90% identities.
The following organisms are all homologous and contain a similar sequence for MSTN as in humans.
Figure
1. https://biology-forums.com/index.php?action=gallery;sa=view;id=686
1. https://biology-forums.com/index.php?action=gallery;sa=view;id=686
This site was created as part of a project for Genetics 564