A beginning graduate student decides to try to reconstitute chromatin from Arabidopsis in vitro . He has a tube of purified Arabidopsis DNA, but he does not have purified histones from Arabidopsis ....

A beginning graduate student decides to try to reconstitute chromatin from
Arabidopsis in vitro. He has a tube of purified
Arabidopsis
DNA, but he does not have purified histones from
Arabidopsis. He does have tubes of purified histones from other species, however. He has H1 from humans, H2A and H2B from
Drosophila, H3 from
C. elegans, and H4 from maize. He knows the exact salt conditions and the proper pH for reconstitution, so he decides to mix them together. The experiment works, at least somewhat. (This type of reconstruction experiment has been done, although not with these components from these organisms.) a. What part of the structure of a chromosome do you think he was able to reconstitute? Describe this structure in as much detail as you can. b. He learns that he can reconstitute the same chromatin structure, even if he leaves out one component. Which component could he leave out? (In other words, which of these components is missing when the structure in (a) is assembled?) c. The fact that he is able to reconstitute this structure provides some important information about the underlying structure of the chromosome. What are some of the inferences that can be drawn from this successful experiment?