Between 1957 and 1959, Arthur Pardee, Francois Jacob, and Jacques Monod conducted a set of experiments at the Pasteur Institute in Paris, France, that was later called the PaJaMa Experiments, a moniker derived from the researchers' last names. In these experiments, they described how genes of a species of single-celled bacteria, called Escherichia coli (E. coli), controlled the processes by which enzymes were produced in those bacteria. In 1959, the researchers published their results in a paper titled 'The Genetic Control and Cytoplasmic Expression of 'Inducibility' in the Synthesis of b-galactosidase by E. coli'. When they compared mutated strains of E. coli to a normal strain, Pardee, Jacob, and Monod identified the abnormal regulation processes and enzymes produced by the mutated genes. The results showed how enzymes break down the molecules that the bacteria ingested. The PaJaMas experiments uncovered some of the molecular mechanisms that regulate how some genes yield enzymes in many species.

Roy John Britten studied DNA sequences in the US in the second
half of the twentieth century, and he helped discover repetitive
elements in DNA sequences. Additionally, Britten helped propose
models and concepts of gene regulatory networks. Britten studied the
organization of repetitive elements and, analyzing data from the
Human Genome Project, he found that the repetitive elements in DNA
segments do not code for proteins, enzymes, or cellular parts.
Britten hypothesized that repetitive elements helped cause cells to
differentiate into more specific cell kinds among different
organisms.

The Cell in Development and Inheritance, by Edmund Beecher Wilson, provided a textbook introduction to cell biology for generations of biologists in the twentieth century. In his book, Wilson integrated information about development, inheritance, chromosomes, organelles, and the structure and functions of cells. First published in 1896, the book started with 371 pages, grew to 483 pages in the second edition that appeared in 1900, and expanded to 1,231 pages by the third and final edition in 1925. Wilson dedicated the book to the cell biologist Theodor Boveri, whose work established the roles of chromosomes in cell division. With its explanations and many illustrations and diagrams, The Cell in Development and Inheritance enabled embryologists to better understand development in terms of cell structure and function.

Walter Stanborough Sutton studied grasshoppers and connected the phenomena of meiosis, segregation, and independent assortment with the chromosomal theory of inheritance in the early twentieth century in the US. Sutton researched chromosomes, then called inheritance mechanisms. He confirmed a theory of Wilhelm Roux, who studied embryos in Breslau, Germany, in the late 1880s, who had argued that chromosomes and heredity were linked. Theodor Boveri, working in Munich, Germany, independently reached similar conclusions about heredity as Sutton. Later scientists named the theory The Sutton-Boveri Theory, or The chromosomal theory of inheritance.

Schizophrenia affects 1.1% of the population worldwide. Schizophrenia is a complex, multifactorial disorder. Stress can trigger psychotic episodes and exacerbate schizophrenic symptoms. For humans, one gene implicated in stress and schizophrenia in humans is the early growth response 3 (EGR3). Patients with genomic variations in EGR3 have reduced levels of EGR3 in the prefrontal brain region compared with healthy patients. Schizophrenic patients also have less serotonin 2A receptor (5HT2AR), which is coded by the gene Htr2a, in their prefrontal cortex. Mice that are Egr3-deficient also have decreased levels of 5HT2AR, suggesting that Egr3 may be involved in the regulation of 5HT2AR. The purpose of the experiment is to determine if EGR3 binds to the Htr2a gene promoter region by using a Chromatin immunoprecipitation (ChIP) assay. We will use ECS to increase EGR3 expression. Previously we have identified two upstream sites of interest where EGR3 potentially binds to the Htr2a gene, one which is distal and one proximal to the transcription start site. After ECS, increased binding is seen in the Htr2a distal region with EGR3 via the ChIP assay. Increased binding was not observed at either of the promoter sites; however, the t-test comparing the distal site of the ECS and the No ECS groups to have a p-value of 0.056, suggesting that increasing the number of animals (n=7) could possibly give a more accurate representation to test our hypothesis. However, the experiment still suggests increased expression and that EGR3 may bind to the distal site of Htr2a. Keywords: stress, environment, genetics, schizophrenia, EGR3, chromatin immunoprecipitation