(6 pts.) A survey of soil samples from Patagonia uncovers two new species of fungi (A and B). Chromatin was extracted from each species and treated to remove non-histone proteins, followed by a treatment with micrococcal nuclease (MNase). MNase cuts DNA not protected by proteins but it cannot cut DNA bound by histone proteins. After the MNase treatment, the DNA is purified from the histones and analyzed by gel electrophoresis. The figure shows the patterns of DNA bands for the two new species, after staining the gel with ethidium bromide.
The number of base pairs (bp) in the bands is shown at the left of the gel.
Based on the observed band patterns what can you tell about the spacing of the nucleosomes in the chromatin of each species?
by SOO — GOO — 400 — ?00
Species A B
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