Forward genetics a bare minimum for the appearance of specific phenotypes. However, such initial screens were either incomplete as they were missing redundant loci and epigenetic effects, and such screens were difficult to undertake for certain phenotypes that lack directly measurable phenotypes. Additionally a classical genetics approach takes significantly longer. Gregor Mendel experimented with pea plant phenotypes and published his conclusions about genes and inheritance in 1865. Around the early 1900s Thomas Hunt Morgan was mutating Drosophila using radium and attempting to find heritable mutations Alfred Sturtevant later began mapping genes of Drosophila with mutations they had been following. In the 1990s
Christianity and science its leadership, grew rapidly in Europe in the 11th and 12th centuries. St.Thomas Aquinas, the Church's "model theologian," argued that reason is in harmony with faith, and that reason can contribute to a deeper understanding of revelation, and so encouraged intellectual development. The Church's priest-scientists, many of whom were Jesuits, have been among the leading lights in astronomy, genetics, geomagnetism, meteorology, seismology, and solar physics, becoming some of the "fathers" of these sciences. Examples include important churchmen such as the Augustinian abbot Gregor Mendel (pioneer in the study of genetics), Roger Bacon (a Franciscan friar who was one of the