  We review pro and contra of the hypothesis that generic polymer properties of
topological constraints are behind many aspects of chromatin folding in
eukaryotic cells. For that purpose, we review, first, recent theoretical and
computational findings in polymer physics related to concentrated,
topologically-simple (unknotted and unlinked) chains or a system of chains.
Second, we review recent experimental discoveries related to genome folding.
Understanding in these fields is far from complete, but we show how looking at
them in parallel sheds new light on both.
