How can model organisms be used to study genes?
Model organisms are used to study certain biological processes and diseases without having to conduct experiments on humans. Different species of model organisms can be used based on relevant factors such as their similarity to humans (specific genes, whole genome, or biologically/physiologically), the cost to maintain them, and their generation times. Using a variety of methods, researchers can manipulate specific genes in model organisms to study those genes and their functions.
What model organisms can be used to study schizophrenia and C4A?
Mouse (Mus musculus)
The mouse homolog of C4A is named "sex-limited protein" and is expressed mainly in the liver . Although C4A knockout mice lines have not been studied, knockouts of other genes related to schizophrenia in mice (such as DISC1, NRG1, ERBB4, Dysbindin and Reelin) have been shown to cause behavioral defects and are a useful way to model schizophrenia .
Zebrafish (Danio rerio)
Although there have not been any C4A mutant zebrafish identified in the literature thus far, zebrafish have been utilized to discover novel schizophrenia genes and to model the underlying processes of the disease. Some of the complex psychological symptoms associated with schizophrenia cannot be studied in zebrafish, however the basic development defects implicated by certain schizophrenia genes has been studied . In 2007, researchers discovered a zebrafish endophenotype associated with schizophrenia called prepulse inhibition (PPI) . PPI is involved in the startle response and is impaired in schizophrenia patients .
C4A knockout lines have not been studied in model organisms since the association between variants of C4A and schizophrenia was recently discovered in 2016 . In the coming years, researchers will likely be studying C4A knockouts and evaluating the behavioral and anatomical phenotypes that have already been established in model organisms such as mice and zebrafish.