TAILIEUCHUNG - Báo cáo sinh học: " Measuring genetic distances between breeds: use of some distances in various short term evolution models"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học thế giới đề tài: Measuring genetic distances between breeds: use of some distances in various short term evolution models | 481 Genet Sei. Evol. 34 2002 481-507 INRA EDP Sciences 2002 DOI gse 2002019 Original article Measuring genetic distances between breeds use of some distances in various short term evolution models Guillaume Laval Magali SanCristobal Claude Chevalet Laboratoire de génétique cellulaire Institut national de la recherche agronomique BP 27 Castanet-Tolosan cedex France Received 9 May 2001 accepted 21 December 2001 Abstract - Many works demonstrate the benefits of using highly polymorphic markers such as microsatellites in order to measure the genetic diversity between closely related breeds. But it is sometimes difficult to decide which genetic distance should be used. In this paper we review the behaviour of the main distances encountered in the literature in various divergence models. In the first part we consider that breeds are populations in which the assumption of equilibrium between drift and mutation is verified. In this case some interesting distances can be expressed as a function of divergence time t and therefore can be used to construct phylogenies. Distances based on allele size distribution such as 5m 2 and derived distances taking a mutation model of microsatellites the Stepwise Mutation Model specifically into account exhibit large variance and therefore should not be used to accurately infer phylogeny of closely related breeds. In the last section we will consider that breeds are small populations and that the divergence times between them are too small to consider that the observed diversity is due to mutations divergence is mainly due to genetic drift. Expectation and variance of distances were calculated as a function of the Wright-Malecot inbreeding coefficient F. Computer simulations performed under this divergence model show that the Reynolds distance 57 is the best method for very closely related breeds. microsatellites breeds divergence mutation genetic drift 1. introduction Assuming a species-like evolution pattern evolution scheme as

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