ترغب بنشر مسار تعليمي؟ اضغط هنا

A limit theorem for trees of alleles in branching processes with rare neutral mutations

639   0   0.0 ( 0 )
 نشر من قبل Jean Bertoin
 تاريخ النشر 2009
  مجال البحث
والبحث باللغة English
 تأليف Jean Bertoin




اسأل ChatGPT حول البحث

We are interested in the genealogical structure of alleles for a Bienayme-Galton-Watson branching process with neutral mutations (infinite alleles model), in the situation where the initial population is large and the mutation rate small. We shall establish that for an appropriate regime, the process of the sizes of the allelic sub-families converges in distribution to a certain continuous state branching process (i.e. a Jirina process) in discrete time. It^os excursion theory and the Leevy-It^o decomposition of subordinators provide fundamental insights for the results.



قيم البحث

اقرأ أيضاً

115 - Mathias Rousset 2017
In this paper, we prove convergence in distribution of Langevin processes in the overdamped asymptotics. The proof relies on the classical perturbed test function (or corrector) method, which is used both to show tightness in path space, and to ident ify the extracted limit with a martingale problem. The result holds assuming the continuity of the gradient of the potential energy, and a mild control of the initial kinetic energy.
We consider the branching process in random environment ${Z_n}_{ngeq 0}$, which is a~population growth process where individuals reproduce independently of each other with the reproduction law randomly picked at each generation. We focus on the super critical case, when the process survives with a positive probability and grows exponentially fast on the nonextinction set. Our main is goal is establish Fourier techniques for this model, which allow to obtain a number of precise estimates related to limit theorems. As a consequence we provide new results concerning central limit theorem, Edgeworth expansions and renewal theorem for $log Z_n$.
321 - Nobuo Yoshida 2007
We consider branching random walks in $d$-dimensional integer lattice with time-space i.i.d. offspring distributions. When $d ge 3$ and the fluctuation of the environment is well moderated by the random walk, we prove a central limit theorem for the density of the population, together with upper bounds for the density of the most populated site and the replica overlap. We also discuss the phase transition of this model in connection with directed polymers in random environment.
Let $(Z_n,ngeq 0)$ be a supercritical Galton-Watson process whose offspring distribution $mu$ has mean $lambda>1$ and is such that $int x(log(x))_+ dmu(x)<+infty$. According to the famous Kesten & Stigum theorem, $(Z_n/lambda^n)$ converges almost sur ely, as $nto+infty$. The limiting random variable has mean~1, and its distribution is characterised as the solution of a fixed point equation. par In this paper, we consider a family of Galton-Watson processes $(Z_n(lambda), ngeq 0)$ defined for~$lambda$ ranging in an interval $Isubset (1, infty)$, and where we interpret $lambda$ as the time (when $n$ is the generation). The number of children of an individual at time~$lambda$ is given by $X(lambda)$, where $(X(lambda))_{lambdain I}$ is a c`adl`ag integer-valued process which is assumed to be almost surely non-decreasing and such that $mathbb E(X(lambda))=lambda >1$ for all $lambdain I$. This allows us to define $Z_n(lambda)$ the number of elements in the $n$th generation at time $lambda$. Set $W_n(lambda)= Z_n(lambda)/lambda^n$ for all $ngeq 0$ and $lambdain I$. We prove that, under some moment conditions on the process~$X$, the sequence of processes $(W_n(lambda), lambdain I)_{ngeq 0}$ converges in probability as~$n$ tends to infinity in the space of c`adl`ag processes equipped with the Skorokhod topology to a process, which we characterise as the solution of a fixed point equation.
141 - Jean Bertoin 2009
We consider a (sub) critical Galton-Watson process with neutral mutations (infinite alleles model), and decompose the entire population into clusters of individuals carrying the same allele. We specify the law of this allelic partition in terms of th e distribution of the number of clone-children and the number of mutant-children of a typical individual. The approach combines an extension of Harris representation of Galton-Watson processes and a version of the ballot theorem. Some limit theorems related to the distribution of the allelic partition are also given.
التعليقات
جاري جلب التعليقات جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
mircosoft-partner

هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا