**4. Conclusions**

part of the Kokai including the Oh and Sakura Rs (Fig. 9). 77.4 to 99.0 % of individuals of Pops K9, 10, 12, 13, 15 to 18 (a total of 8 populations) in the Kokai occupied members of Cluster II. Cluster II also implied to be the genetic population of the middle and upper parts of the Kokai R. The remaining individuals of Pops K1, K7, K11, K14, K19 and K20 (a total of 6 populations) in the Kokai R. were mainly classified into members of admixtures of Clus‐ ters I & II. In the analysis of Cluster B, almost all individuals (more than 99.1 %) of Pops G and A1 in the Gogyo and Ara Rs. and Pop A2 in the Ara R. were assigned to Clusters III and IV, respectively (Fig. 8). Cluster III and IV reflected the genetic populations of the Gogyo

An Integrated View of the Molecular Recognition and Toxinology - From Analytical Procedures to Biomedical

**Figure 9.** Spatial distribution and composition of genetic clusters in populations (unpublished figure). Size of circle

Consequently the four genetic populations (Clusters I to IV) and a mixed genetic population (admixture of Cluster I & II) were confirmed in the populations using this clustering analy‐ sis. Clusters I, II and a pair of Clusters III & IV nearly coincided with a pair of GroupTree 2 & 3, GroupTree 4 and GroupTree 1 in the phylogenetic tree, respectively (Fig. 7). Moreover, the presence of the mixed genetic population, which could not be usually detected in a phyloge‐ netic tree, was founded by the cluster analysis. As discussed in the previous studies [69-71, 73], this admixture of Cluster I & II may be established through gene flow caused by mi‐ grant; thus, events relative to individual movement and breeding could have occurred

reflects that of population.

Applications

366

among some populations in the past.

and one of Ara R. and another of the Ara R., respectively (Fig. 9).

A series of the exhaustive genetic analysis in this chapter demonstrated that the populations of the Hotoke loach indicated to have moderate genetic diversity and to be supported with 4 genetic populations, of which distributions depended on the populations and the geographi‐ cal locations. These 2 genetic characteristics showed that there could not be serious genetic concerns at present and the populations might be available as valuable biological resources such as bird food. To fulfill the effective utilization of this loach in near future, both biomed‐ ical and nutritional investigations for component contained in the body may also have to be practiced in the next research subjects along with proposing an optimal management plan for conserving the populations.

Further, the following 2 suggestions based on the results of this analysis should be realized in conduct of the next research. First, to sustain the present genetic features, habitats of the populations have to be maintained with monitoring the population size. As it is repeatedly described in the above, but reduction of the population size often appears to cause degrada‐ tion of the genetic diversity and the lost genetic diversity could never be regained in the populations [30-33]. Avoiding such a decrease in the genetic diversity, habitat conservation might be important for a population management. It was also investigated that this species had relatively strict water temperature resistance compared with other common freshwater fish [48, 49]; hence the control of the water quality, especially water temperature could be one of essential factors for conserving habitats of the populations.

Second, spatial distribution and composition of the genetic populations should be taken ac‐ count in the population management. In this area the genetic populations could be establish‐ ed by only geographical factors such as river and ground conditions (Fig. 9) and related to no human activities. The foregoing genetic populations often appear a kind of genetic heri‐ tages and it is recommended that their distributions do not have to be disturbed artificially [30-33, 35]. If perchance size diminishment of a specific population is observed and there is only individual translocation as a method to recover the population, selections of translated individuals and populations should be advisedly carried out based on the distribution of the genetic populations. Finally there still may be various and many biological resources left in the rural ecosystem in Japan. Genetic analyses performed in this chapter would have to con‐ tribute substantially to exploration and beneficial utilization of these resources.
