@article{oai:twcu.repo.nii.ac.jp:00024652,
 author = {福田, 一郎},
 issue = {2},
 journal = {東京女子大學論集},
 month = {Mar},
 note = {Recently population biologists have become deeply interested in the problem of species concept. It is thought that the problem should be discussed by all biologists on the bases of all biological views. This paper has discussed the species problem on the basis of population genetics. Population genetics uses "Mendelian Population" as a standard unit, which is a reproductive community of individuals which share in a common gene pool (Do-bzhansky 1951). For example, Trillium kamtschaticum P_<ALL>. has natural population of a various type (Fig. 1). Kojima population is a small number which shows the same chromosome composition in all individuals. By contrast, Toyoni population is a large number which shows the same chromosome composition in the samples from two quadrates Q_3 and Q_4 (P>0.10, non-significant in statistical). Erimo population has a disjunctive distribution on both sides of the small mountain. However, A and B samples from each position show the same chromosome composition (P>0.10). Because the gene exchanges are practically continuing, the above three are called "Mendelian Population". Such a mendelian population forms a "Race", which show a different chromosome variation. Three races, S, N and E, were discovered by chromosome analyses in northern Japan (Fig. 2). The races form the "Species", Trillium kamtschaticum P_<ALL>. A species cannot exchange genes among other species under normal conditions because an isolating mechanism has developed. Therefore, a species may be difined as a reproductive community which has possible gene exchange. The species is not a static unit. It is one stage in the process of evolution. Trillium ovatum is distributed in the Pacific coast and the Rocky mountain regions of western United States and Canada. Population in the Pacific coast region have a simple variation in their chromosome composition, whereas population in the Rocky mountain region have a complex variation in their composition (Fig. 3). It seems possible from the above data that the plants of the Pacific, coast region were fixed by a natural selection, but migrants which have gone from the coast region to the Rocky mountain region, have had gene exchanges and formed a new adaptation in the mountain region after the Wisconsin ice age. At present, the Harney and Great basins exist as a great isolating mechanism between the coast and mountains. This is one example of speciation in the process of the evolutionary pattern. It must be divided into two species in the not-too-distant future. In conclusion, a characteristic view of the species concept from the population genetics accepts the definition of the species having the possibility of gene exchange and the meaning of a dynamic unit as a stage in the process of evolution. I wish to express my gratitude to Prof. Mrs. John N. Nicholson for her English teaching to me.},
 pages = {117--130},
 title = {"種"の概念 : その集団遺伝学的見解},
 volume = {16},
 year = {1966}
}