Finally, the morphological distinctiveness of populations in genetic units G remains to be tested.
These studies not only revealed genetic distinctiveness of populations from different Rhine tributaries, but also found sympatric co-existence of genetically distinct populations within rivers, suggesting at least partial reproductive isolation after secondary contact.
Parker et al. (1999) found Monkey Spring to be the genetically most differentiated population and the distinctiveness of this population is further supported by geological, ecological, and life history evidence.
A similar pattern is observed in an MDS plot of only Native American individuals, except that the Aché population forms a distinct cluster, in agreement with previous population genetic evidence of the distinctiveness of this population (Battilana et al. 2002; Kohlrausch et al. 2005; Wang et al. 2007; Callegari-Jacques et al. 2008).
However, different analyses disagree about which populations are distinct and no analysis strongly supported the distinctiveness of any population.
Also consistent is the distinctiveness of a population that may represent an undescribed species, from Pedernales Springs [ 10].
However, as more standardized data becomes available within a region, it will be possible to determine the distinctiveness of each population.
The mitochondrial phylogenetic analyses supported the existence of a seventh isolated lineage, J. Awlime, however clustering analysis and the nuclear phylogeny did not support the distinctiveness of this population, possibly because of the small sampling size.
If genetic variation in the existing population is low, or immigration high, trait replacement might occur through gene flow rather than evolution in isolation, reducing the genetic distinctiveness of this population complex (Waples et al. 2004).
Significant isolation by distance also confirmed the genetic proximity of geographically closely located populations, and genetic distinctiveness of remote populations.
