Benchmark 10H
Historical Perspectives: Explaining the Diversity of Life
Grades 9-12, page 255

After the publication of Origin of Species, biological evolution was supported by the rediscovery of the genetics experiments of an Austrian monk, Gregor Mendel, by the identification of genes and how they are sorted in reproduction, and by the discovery that the genetic code found in DNA is the same for almost all organisms.
 

See Content Standard G History and Nature of Science (grades 9-12): Historical Perspectives