Fst increases more rapidly with distance for mitochondrial DNA than for autosomal DNA for some ...

Fst indicates the degree of genetic differentiation between populations. When it comes to increases/decreases in population size, the number of segregating sites is more affected by current population size, and nucleotide diversity is more affected by past population size. In a population that is going through a bottleneck, for example. the number of segregating sites will fall more rapidly than that of a nucleotide diversity leading to a positive Tajima's D value. In a population that is increasing from a bottleneck the number of segregating sites will increase more rapidly than that of nucleotide diversity leading to a negative D.