DNA Day celebration, not an annual holiday. Every year from 2003 onward, annual DNA Day celebrations have been organized by the National Human Genome Research Institute (NHGRI), starting as early as April 23 in 2010, April 15 in 2011 and April 20 in 2012. April 25 has since been declared "International DNA Day" and "World DNA Day" by several groups. DNA Day National DNA Day is a 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, on
Solenoid (DNA) Solenoid (DNA) The solenoid structure of chromatin is a model for the structure of the 30 nm fibre. It is a secondary chromatin structure which helps to package eukaryotic DNA into the nucleus. Chromatin was first discovered by Walther Flemming by using aniline dyes to stain it. In 1974, it was first proposed by Roger Kornberg that chromatin was based on a repeating unit of a histone octamer and around 200 base pairs of DNA. The solenoid model was first proposed by John Finch and Aaron Klug in 1976. They used electron microscopy images and X-ray diffraction patterns to determine