Within and between population diversity
Partitioning of genetic diversity within and between populations is an important factor to be considered in most conservation efforts,especially in the case of in situ conservation . Measures of genetic variation in space are strongly affected by correlation between subdivision used for sampling, especially with regard to variation in gene frequencies across populations. Usually the variance of gene frequencies is standardized by obtaining the mean gene frequency. Under the model of isolation by distance (usually called the ‘ stepping stone’ model),at the stationary state the correlation between the gene frequencies of two populations falls exponentially with the geographic distance between them. A method has been developed to compute identity coefficients of two gene in the stepping-stone model with partial selfing, which is often the case with outbreeding species.
 Though a part of the differences in subsamples or subdivisions is the result of adaptation to different environmental niches, local gene statistical properties that reflect their limitation to the interval 0-1 and the sampling behavior that occurs at reproduction. The pattern of migration additionally imposes a spatial structure. Migration, dependent on the distance between the subdivisions generates a correlation between neighbouring populations.