According to Wikipedia, National DNA Day is observed by biologists, science teachers and students, anyone interested in genetics. The day celebrates the discovery and understanding of DNA and the scientific advances that understanding has made possible.
National DNA Day is a United States holiday celebrated on April 25. It commemorates the day in 1953 when James Watson, Francis Crick, Maurice Wilkins, Rosalind Franklin and colleagues published papers in the journal Nature on the structure of DNA. Furthermore, in early April 2003 it was declared that the Human Genome Project was very close to complete, and “the remaining tiny gaps were considered too costly to fill. In the United States, DNA Day was first celebrated on April 25, 2003, by proclamation of both the Senate and the House of Representatives.