Much has changed since Streisinger initially proposed the zebrafish as a model system for developmental biology. Originally designed as a vertebrate genetic model for developmental research, the zebrafish today plays an important and increasing role in a wide range of scientific fields, including biomedicine, neurology, genomics, toxicology, and evolutionary biology. Parallel to the growth in our understanding of zebrafish biology has been a fast increase in the number of wild-type lines utilised for research. A wild-type line has traditionally been described as a closed breeding population of fish with no specified phenotypic alterations. Because certain lines with known mutations are utilised as wild-type lines, the phrase “standard line” is more commonly employed. Forward genetic mutagenesis and mutation introgression onto known backgrounds have also resulted in a large number of mutant lines with genetic backgrounds comparable to those of a given wild-type line. The Zebrafish Information Network presently has 19 wild-type lines as of publishing. These lines define the genetic backgrounds that are now utilised in the majority of zebrafish labs. The growing number of zebrafish strains utilised in research poses a number of serious concerns. The precise identification of zebrafish lines is essential in determining the generality of study findings. Because each zebrafish line is generally descended from a different founder stock, it may have a distinct genetic background. The genetic background of a particular line might have significant eVects on experimental findings due to epistatic gene activity. DiVerences across the backgrounds of diVerent wild-type lines might result in a particular mutation exhibiting diVerent phenotypes, which could have a range of eVects. Because of the widespread use of forward genetic mutagenesis screens in developmental biology, this is especially relevant. The possibility of genetic background diversity among lines emphasises the necessity for a precise naming system that allows correct identification of the genetic lines and backgrounds utilised in studies.

The current standard (wild-type) zebrafish line nomenclature is given at. Standard strain names are nonitalicized with the initial letter capitalised, whereas abbreviations are all uppercase and nonitalicized. In its current form, zebrafish standard line nomenclature does not account for the complete range of potential standard line types. Lines should be assigned a unique identification (name) that also shows their connection to other lines. These historically descriptive names will grow more complicated as line pedigrees develop. Current mouse nomenclature covers circumstances that zebrafish have not yet defined, such as inbred lines, substrain derivation, hybrid strains, and congenic lines that differ by a single allele. Zebrafish lines are now called based on their history, line originators, or fish suppliers. Informal line nomenclature has also been used to mark how many generations a line has passed through in a propagation system.

According to common knowledge, standard lines are largely employed to provide genetic backgrounds for induction, modification, mapping, and mutation detection. This is the primary motivation for the development of all major zebrafish wildtype lines. However, as zebrafish become more widely used as a genetic model organism, new applications in disciplines such as toxicology and evolutionary biology will emerge. Even within the current zebrafish research community, there are frequently competing agendas when it comes to the usage of standard lines. A line suitable for mutagenesis, for example, may not be suitable for toxicological research or genetic mapping. Because embryonic lethals have been eliminated from the population, several lines (AB, TU, and AB/TU) are often utilised for mutagenic screening. Furthermore, alleles that disrupt or interfere with embryonic phenotypes are frequently eliminated, allowing for a more fruitful screen for embryonic morphologies. In certain situations, specific alleles are required for complementation, enhancer, or suppressor testing. Prior to mutagenesis, suitable genetic material must be introgressed into the background of the standard line in these cases. Mapping strains (often SJD and WIK) differ sufficiently from AB and TU backgrounds to yield effective sets of polymorphic molecular markers. Mapping compatibility with another line should be established in order to map new mutations rapidly. SJD and WIK are the most commonly utilised mutation mapping genes on the AB and TU backgrounds. The highly inbred SJD provides more consistently mappable markers, but the line is more difficult to maintain for many people. WIK is also thought to be molecularly different enough from AB and TU to be useful in mapping. TL is a line that has not been cleansed of background mutations, but is thought to be extremely resilient and helpful for easy mutant maintenance.