{"doi":"10.1101/2022.02.01.478588","title":"Crumpled polymer with loops recapitulates key features of chromosome organization","abstract":"Chromosomes are exceedingly long topologically-constrained polymers compacted in a cell nucleus. We recently suggested that chromosomes are organized into loops by an active process of loop extrusion. Yet loops remain elusive to direct observations in living cells; detection and characterization of myriads of such loops is a major challenge. The lack of a tractable physical model of a polymer folded into loops limits our ability to interpret experimental data and detect loops. Here, we introduce a new physical model – a polymer folded into a sequence of loops, and solve it analytically. Our model and a simple geometrical argument show how loops affect statistics of contacts in a polymer across different scales, explaining universally observed shapes of the contact probability. Moreover, we reveal that folding into loops reduces the density of topological entanglements, a novel phenomenon we refer as “the dilution of entanglements”. Supported by simulations this finding suggests that up to ∼ 1 − 2Mb chromosomes with loops are not topologically constrained, yet become crumpled at larger scales. Our theoretical framework allows inference of loop characteristics, draws a new picture of chromosome organization, and shows how folding into loops affects topological properties of crumpled polymers.","journal":"bioRxiv (Cold Spring Harbor Laboratory)","year":2022,"id":296493,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":34,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9422,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2022-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":983312,"name":"B. Slavov","orcid":"0009-0001-5230-6779","position":1,"is_corresponding":false},{"id":983313,"name":"Sergey Belan","orcid":"0000-0002-8790-3346","position":2,"is_corresponding":false},{"id":355547,"name":"Maxim Imakaev","orcid":"0000-0002-5320-2728","position":3,"is_corresponding":false},{"id":135507,"name":"Hugo B. Brandão","orcid":"0000-0001-5496-0638","position":4,"is_corresponding":false},{"id":109520,"name":"Leonid A. Mirny","orcid":"0000-0002-0785-5410","position":5,"is_corresponding":false},{"id":983311,"name":"Kirill Polovnikov","orcid":"0000-0001-9903-9623","position":0,"is_corresponding":true}],"reference_count":62,"raw_metadata":null,"created_at":"2026-07-19T00:31:16.555318Z","pmid":null,"pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}