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Recent population decline and selection shape diversity of taxol‐related genes
Author(s) -
BURGARELLA C.,
NAVASCUÉS M.,
ZABALAGUIRRE M.,
BERGANZO E.,
RIBA M.,
MAYOL M.,
VENDRAMIN G. G.,
GONZÁLEZMARTÍNEZ S. C.
Publication year - 2012
Publication title -
molecular ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.619
H-Index - 225
eISSN - 1365-294X
pISSN - 0962-1083
DOI - 10.1111/j.1365-294x.2012.05532.x
Subject(s) - biology , approximate bayesian computation , balancing selection , natural selection , evolutionary biology , selection (genetic algorithm) , population , genetic diversity , effective population size , gene , genetics , genetic variation , demography , artificial intelligence , sociology , computer science
Taxanes are defensive metabolites produced by Taxus species (yews) and used in anticancer therapies. Despite their medical interest, patterns of natural diversity in taxane‐related genes are unknown. We examined variation at five main genes of Taxus baccata in the Iberian Peninsula, a region where unique yew genetic resources are endangered. We looked at several gene features and applied complementary neutrality tests, including diversity/divergence tests, tests solely based on site frequency spectrum (SFS) and Zeng’s compound tests. To account for specific demography, microsatellite data were used to infer historical changes in population size based on an Approximate Bayesian Computation (ABC) approach. Polymorphism‐divergence tests pointed to positive selection for genes TBT and TAT and balancing selection for DBAT . In addition, neutrality tests based on SFS found that while a recent reduction in population size may explain most statistics’ values, selection may still be in action in genes TBT and DBAT , at least in some populations. Molecular signatures on taxol genes suggest the action of frequent selective waves with different direction or intensity, possibly related to varying adaptive pressures produced by the host–enemy co‐evolution on defence‐related genes. Such natural selection processes may have produced taxane variants still undiscovered.