Canonical correspondence analysis for estimating spatial and environmentaleffects on microsatellite gene diversity in brook charr (Salvelinus fontinalis)

The understanding of the relationships between environmental factors and ev olutionary forces is of importance to preserve opportunities for the contin uation of dynamic evolutionary and ecological processes. This involves the identification and quantification of the relative importance of environment al factors that may influence these processes. Nevertheless, environmental factors are generally interpreted in terms of hypothetical inferences as re lationships between environmental and genetic variables are often difficult to quantify. In this study, we used a statistical framework based on canon ical correspondence analysis in order to determine the relative contributio n of drainage pattern and environmental factors in structuring inter- and i ntrapopulational genetic diversity among brook charr populations as depicte d by microsatellite analysis. These procedures simultaneously analyse sever al sets of variables and determine their relative contribution. The results revealed the influence of drainage pattern, altitude and human-induced fac tors on the pattern of genetic diversity and, particularly, the important r ole of historical events in explaining patterns of contemporary genetic div ersity among populations. The statistical framework used in this study prov ides an efficient way to empirically relate variations of genetic diversity and descriptive variables in general.