Staging of porcine embryos: Comparison of Standard Event System‐based statistical clusters with a Carnegie‐based staging system.

Background: Methods to compare events defined as newly occurring characters in development has advanced vertebrate developmental research but events are not easily extrapolated into traditional staging systems used in biomedical research. Results: First, we scored 95 porcine embryos in the age range of 15 to 33 days post conception by stereomicroscopy using to a slightly modified version of the Standard Event System (SES). Subsequent statistical clustering allowed the embryos to be grouped into 15 clusters. Staging of the same embryos in a way that generally follow the description of external features of human embryos in the Carnegie stages 10 to 23 allowed us to describe 14 stages of porcine embryonic development that correlate to the Carnegie stages of human development with minor species differences. When arranged by average age, the statistic clusters had a distribution that correlated well with the stages produced by the Carnegie‐based staging system. Conclusions: Statistical analysis of developmental events allow grouping of porcine embryos into clusters that can be extrapolated into a Carnegie‐based staging system, thus serving the dual purpose of facilitating the use of the pig as a biomedical model animal and providing data for integrating porcine developmental events into a phylogenetic context. Key Findings: Porcine embryos (15‐33 dpi) were successfully grouped into 15 clusters by using a modified standard event system based on external characteristics and subsequent statistical clustering.Porcine embryos (15‐33 dpi) were staged using Carnegie‐based external features and some minor differences of porcine and human embryonic development were identified.The two staging systems generally correlate well. [ABSTRACT FROM AUTHOR]