The history of genetics is generally held to have started with the work of an Augustinian friar, Gregor Mendel. His work on pea plants, published in 1866, described what came to be known as Mendelian Inheritance. In the centuries before—and for several decades after—Mendel's work, a wide variety of theories of heredity proliferated (see below). 1900 marked the "rediscovery of Mendel" by Hugo de Vries, Carl Correns and Erich von Tschermak, and by 1915 the basic principles of Mendelian genetics had been applied to a wide variety of organisms—most notably the fruit fly Drosophila melanogaster. Led by Thomas Hunt Morgan and his fellow "drosophilists", geneticists developed the Mendelian-chromosome theory of heredity, which was widely accepted by 1925. Alongside experimental work, mathematicians developed the statistical framework of population genetics, bring genetical explanations into the study of evolution.
With the basic patterns of genetic inheritance established, many biologists turned to investigations of the physical nature of the gene. In the 1940s and early 1950s, experiments pointed to DNA as the portion of chromosomes (and perhaps other nucleoproteins) that held genes. A focus on new model organisms such as viruses and bacteria, along with the discovery of the double helical structure of DNA in 1953, marked the transition to the era of molecular genetics. In the following years, chemists developed techniques for sequencing both nucleic acids and proteins, while others worked out the relationship between the two forms of biological molecules: the genetic code. The regulation of gene expression became a central issue in the 1960s; by the 1970s gene expression could be controlled and manipulated through genetic engineering. In the last decades of the 20th century, many biologists focused on large-scale genetics projects, sequencing entire genomes.
During 1990s years, Zeng B.J. (Institute of Microbiology, CAS, Beijing) established the concepts of "systems genetics" and "system biological engineering" for the third wave of genetics and engineering of artificial biosystems, and created the genbrain biosystem network of the (world) associates for biosystem science and engineering in Jan. 1999. The history of genetics can be divided into three periods: (1). Mendelian Genetics (the gene theory of Morgan TH); (2). Molecular Genetics (the operon model and central dogma theory). (3). Systems (Pattern) Genetics (structurity theory of biosystems evolution), from 1978 Lewis EB, 1980 Nuslein-Volhard C. and Wieschaus EF discovered segments of body to 1963 -1986 years, Brenner S, Horvitz HR and Sulston JE discovered genes interacting and cell lineages mapping, which is investigated in the field of patterns of signalling network and cells lineage mapping (19th and 20th InternatioNAl Congress of Genetics, 2003 and 2008).
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