Details

Autor(en) / Beteiligte

• Caujapé-castells, Juli

Titel

General G ST and [theta] inflation due to biased intra-population sampling, and its consequences for the conservation of the Canarian Flora

Ist Teil von

• Conservation genetics, 2010-06, Vol.11 (3), p.709

Ort / Verlag

Dordrecht: Springer Nature B.V

Erscheinungsjahr

2010

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• While knowledge of the degree of inter-population genetic differentiation underlies the understanding of microevolutionary processes in any organism, its calculation through G ^sub ST^, F ^sub ST^, or [theta] (which, unlike the previous two, was designed to correct for unequal and small sample sizes) is often based in severely restricted intra-population samples, which are nonetheless tacitly assumed adequate to their accurate estimation. Empirical assessment of the influence of the number and intra-population distribution of samples on the values of G ^sub ST^ and [theta] for several Canarian endemic plants compellingly suggests that (1) contrary to expectations based on simulated datasets, [theta] does not account for empirical sampling bias better than G ^sub ST^; (2) sample sizes being equal, collections scattered across each population's occupancy area entail significantly lower over-estimates of G ^sub ST^ and [theta] than if they only consider one of the population extremes, especially in narrow allogamous taxa with small populations; (3) in small samples, a scattered sampling strategy is significantly less sensitive to G ^sub ST^ inflation than sampling in one of the population extremes; and (4) a software-related component of bias should be considered when pooling values of G ^sub ST^ from different studies to calculate averages. Thus, unlike the sampling methods used for many plant endemics from the Canaries and other regions, collections for a reliable estimation of inter-population differentiation using molecular markers should encompass the whole occupancy area of each population, and include a higher proportion of individuals respect to the total size in narrow endemics than in widespread congeners. Critically, the high average allozyme inter-population differentiation reported for the Canarian endemic Flora is possibly an over-estimate, and could be explained predominantly by the generally biased intra-population sampling associated with G ^sub ST^ estimates, rather than by specific factors of insularity that restrict gene flow radically, as it has been hitherto assumed.[PUBLICATION ABSTRACT]