{"about":{"site":"https://codewithpapers.app","non_affiliation":"Code with Papers and Syntology are not affiliated with, endorsed by, or sponsored by Papers with Code, Meta, or the pwc-archive mirror.","licence":"CC BY-SA 4.0","licence_url":"https://creativecommons.org/licenses/by-sa/4.0/legalcode","attribution":"https://codewithpapers.app/attribution","modified":"archive material modified by Syntology; see the attribution page"},"url":"/paper/likelihood-models-for-forensic-genealogy","title":"Likelihood Models for Forensic Genealogy","arxiv_id":"2010.02985","date":"2020-10-06","proceeding":null,"authors":["William H. Press","John Hawkins"],"abstract":"In the idealized Morgan model of crossover, we study the probability distributions of shared DNA (identical by descent) between individuals having a wide range of relationships (not just lineal descendants), especially cases for which previous work produces inaccurate results. Using Monte Carlo simulation, we show that a particular, complicated functional form with just one continuous fitted parameter accurately approximates the distributions in all cases tried. Analysis of that functional form shows that it is close to a normal distribution, not in shared fraction f, but in the square-root of f. We describe a multivariate normal model in this variable for use as a practical framework for several general tasks in forensic genealogy that are currently done by less-accurate and less well-founded methods.","url_abs":"https://arxiv.org/abs/2010.02985v1","url_pdf":"https://arxiv.org/pdf/2010.02985v1.pdf","source":{"archive":"pwc-archive (Hugging Face), CC BY-SA 4.0","snapshot":"2025-07-28","licence_url":"https://creativecommons.org/licenses/by-sa/4.0/legalcode","row_kind":"links_only","authors_date_abstract":"arXiv metadata, CC0 1.0 (https://info.arxiv.org/help/license), from the Kaggle arXiv metadata snapshot of 2026-09-12"},"code_links":[{"paper_slug":"likelihood-models-for-forensic-genealogy","repo_url":"https://github.com/whpress/forensicgenealogy","is_official":1,"mentioned_in_paper":1,"mentioned_in_github":1,"framework":"none","reach":null}],"tasks":[],"methods":[],"datasets_introduced":[],"methods_introduced":[],"results":[],"syntology":{"atlas_url":null,"mcp":null,"developers":"https://syntology.ai/developers"},"arxiv_metadata":null,"syntology_extracted_results":null}