{ "id": "math/0511743", "version": "v2", "published": "2005-11-30T16:10:16.000Z", "updated": "2006-04-17T20:05:20.000Z", "title": "The process of most recent common ancestors in an evolving coalescent", "authors": [ "P. Pfaffelhuber", "A. Wakolbinger" ], "categories": [ "math.PR", "q-bio.PE" ], "abstract": "Consider a haploid population which has evolved through an exchangeable reproduction dynamics, and in which all individuals alive at time $t$ have a most recent common ancestor (MRCA) who lived at time $A_t$, say. As time goes on, not only the population but also its genealogy evolves: some families will get lost from the population and eventually a new MRCA will be established. For a time-stationary situation and in the limit of infinite population size $N$ with time measured in $N$ generations, i.e. in the scaling of population genetics which leads to Fisher-Wright diffusions and Kingman's coalescent, we study the process $\\mathcal A = (A_t)$ whose jumps form the point process of time pairs $(E,B)$ when new MRCAs are established and when they lived. By representing these pairs as the entrance and exit time of particles whose trajectories are embedded in the look-down graph of Donnelly and Kurtz (1999) we can show by exchangeability arguments that the times $E$ as well as the times $B$ from a Poisson process. Furthermore, the particle representation helps to compute various features of the MRCA process, such as the distribution of the coalescent at the instant when a new MRCA is established, and the distribution of the number of MRCAs to come that live in today's past.", "revisions": [ { "version": "v2", "updated": "2006-04-17T20:05:20.000Z" } ], "analyses": { "subjects": [ "60K35" ], "keywords": [ "common ancestor", "evolving coalescent", "particle representation helps", "mrca process", "reproduction dynamics" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2005math.....11743P" } } }