Breeding planning made easy

The mouse is considered the most commonly used model organism in biomedical research. In particular, genetically modified mouse strains are well suited for the study of gene functions in organs or different cell types as well as the interaction of these with environmental factors. However, the breeding of these special mouse lines requires an appropriate strategy to minimize the production of surplus animals (so-called surpulse animals). Surplus animals are those animals which, for example, do not have the desired genotype or sex, making their use in a study impossible. However, for ethical, practical, financial, and even legal (RL 2010/63/EU) reasons, the minimization of animals used for scientific purposes should be strived for.

Milchevskaya et al. developed the "BreedingCalculator", a software to calculate the minimum number of animals needed for an experiment. Unavoidable and random fluctuations, which are responsible for deviations of breeding results from Mendel's laws, are included by the system. Other parameters integrated into the software are fertility and litter size. Data on litter size are obtained from a collection of litter data from eight different mouse strains at the Laboratory Animal Center of the University of Zurich. They used data from the Jackson Laboratory as the basis for collecting the fertility parameter. The BreedingCalculator software contains the following two functions for breeding calculation:

• First, there is the singleGenotype function, which is intended for breeding where the offspring should have a specific target gene.
• On the other hand, the software offers the multi-Genotype function, which can be used to obtain different genotypes or sexes within a breeding.

According to the manufacturer, the algorithm of their software ensures a better outcome of breeding compared to previous models and thus makes a significant contribution to improving the reproducibility and quality of research. The BreedingCalculator is freely available as an online version, but is also available for download on the GitHub platform.

Sources: https://www.nature.com/articles/s41684-023-01213-1