Question

Who discovered nucleosome?

Answer 1

Nucleosome:

1. Nucleosomes are defined as the basic structural unit of DNA packaging in eukaryotes.
2. Structurally, nucleosomes appear as ‘beads-on-string’ in chromosomes when viewed under an electron microscope.
3. In eukaryotes, DNA is packaged in association with some basic proteins known as histone proteins rich in basic amino acids lysine and arginine. There are five types of histone proteins: H1, H2A, H2B, H3, H4.
4. Four of these histones H2A, H2B, H3, H4 occur in a pair to form a histone octamer or the core of nucleosome. Around this histone octamer is wrapped about 166 bp of DNA.
5. This structure formed by the negatively charged DNA wrapped around the positively charged histone octamer (the core particle) is called nucleosome.

Discovered by: Don and Ada Olins observed nucleosomes for the first time and Kornberg proposed their structure.