- 著者
-
今泉 吉典
- 出版者
- THE MAMMAL SOCIETY OF JAPAN
- 雑誌
- 哺乳動物学雑誌: The Journal of the Mammalogical Society of Japan (ISSN:05460670)
- 巻号頁・発行日
- vol.5, no.6, pp.213-223, 1973
The newly proposed method of taxonomic analysis employing the binomial distribution seems to be usefull to clarify the presence of the reproductive isolation among the members of a population from a continuous region. The binomial distribution is always observed in a local population composed of individuals belonging to a single biological species, but not in a false population containing two or more such species. The reason is briefly explained in the following lines.<BR>In a true local population, variation of a morphological character under the influence of several genes generally shows the normal distribution, so that an allelomorphic type refered to the left or the right half of the distribution always appears at the rate of one half. Therefore, all possible combinations of such allelomorphic types of several qualified characters may occur in the population. Each of the qualified characters here used is composed of two allelomorphic types which have an appearance ratio of one to one, and are not correlated to the other characters and independent with sex, age, season, etc.<BR>If the allelomorphic types of each of the qualified characters are expressed by a capital and a small letters, A a, B b, etc., variations in the number of capital letters in each individual of the true population always constitute a binomial distribution following the laws of combination and probability. But, such binomial distribution cannot occur in a false population composed of two or more distinct species, for the individuals are segregated by the reproductive isolation and random distributions of allelomorphic types are greatly disturbed.<BR>Close correlations between the nature of population and the binomial distribution were confirmed in a true population of <I>Clethriononiys bedfordiae</I> from the main island of Hokkaido and in a false population composed of <I>C. sikotanensis</I> and <I>C. rex</I> from Rishiri Island, off Hokkaido.