Piebald rats and selection : $b An experimental test of the effectiveness of selection and of the theory of gametic purity in Mendelian crosses

"Piebald Rats and Selection" by W. E. Castle and John C. Phillips is a scientific publication written in the early 20th century. This work explores the genetic principles of heredity through experimental tests involving the selection of piebald rats. Its primary focus is on the effectiveness of selection in relation to Mendel's laws, specifically examining the gametic purity within Mendelian crosses. The opening of the text lays a foundation for the investigation into hereditary traits by outlining the significance of Mendelian genetics among biologists. It notes that while there is a general agreement about some aspects of Mendel's theory, significant disagreement exists regarding the nature and function of genetic determiners. The authors describe a multi-year experiment investigating the color patterns of over 25,000 rats aiming to understand how selection influences genetic traits in both positive and negative directions. They introduce the concept of both plus and minus selection series and hint at how their findings challenge prevailing theories regarding pure gametes, setting the stage for detailed empirical results that follow in subsequent chapters.