Genetic sex determination assays in 53 mammalian species: Literature analysis and guidelines for reporting standardization

Erstwhile, sex was determined by observation, which is not always feasible. Nowadays, genetic methods are prevailing due to their accuracy, simplicity, low costs, and time-efficiency. However, there is no comprehensive review enabling overview and development of the field. The studies are heterogeneous, lacking a standardized reporting strategy. Therefore, our aim was to collect genetic sexing assays for mammals and assemble them in a catalogue with unified terminology. Publications were extracted from online databases using key words such as sexing and molecular. The collected data were supplemented with species and gene IDs and the type of sex-specific sequence variant (SSSV). We developed a catalogue and graphic presentation of diagnostic tests for molecular sex determination of mammals, based on 58 papers published from 2/1991 to 10/2016. The catalogue consists of five categories: species, genes, SSSVs, methods, and references. Based on the analysis of published literature, we propose minimal requirements for reporting, consisting of: species scientific name and ID, genetic sequence with name and ID, SSSV, methodology, genomic coordinates (e.g., restriction sites, SSSVs), amplification system, and description of detected amplicon and controls. The present study summarizes vast knowledge that has up to now been scattered across databases, representing the first step toward standardization regarding molecular sexing, enabling a better overview of existing tests and facilitating planned designs of novel tests. The project is ongoing; collecting additional publications, optimizing field development, and standardizing data presentation are needed.