A Study of Deleterious Genes in Some Natural Populations of <i>Drosophila melanogaster</i> in Japan

Relation of Infection to Population Structure in Drosophila melanogaster

“…About 400,000 flies were counted for testing homozygote viabilities of about 400 quasinormal lines and of more than 200 lines of random heterozygotes (Table 8). The mean viabilities of these quasinormals in homozygous condition were similar to that obtained on the sample collected from the Midori Station in the summer of 1959 (31.7%, Minamori and Azuma, 1962). The mean viability of the autumn collection decreased significantly when compared with that of the summer collection.…”

“…It is of interest to students of population genetics to determine whether or not the infection has effects on the population structure of flies. Minamori and Azuma ( 1962) , and Minamori and Saito (1964) have surveyed natural populations of Drosophila melanogaster from Hiroshima City and its vicinity annually from 1959 to 1962. The populations surveyed were recognized to have annual seasonal changes in actual size, that is, the size increases from spring to autumn and contracts in winter.…”

GENETIC VARIABILITIES IN SECOND AND THIRD CHROMOSOMES FROM KOREAN POPULATIONS OF <i>DROSOPHILA MELANOGASTER</i>

“…In S62g, N-2400 ; In S62j, N-17500 ; In K62i, N 3400. The mean of three Ns(-7800) is very much larger than those estimated both for the Korean populations studied in 1957-1958 and the Japanese populations studied by Oshima et al (1961) and Minamori et al (1962), but smaller than that for Madison population (N-20000, estimated by Oshima, 1961 3. The two autosomes differed significantly in three viability categories (incidence in lethals, subvitals supervitals) of the five, considered when chromosomes II and III data are combined.…”

“…More recently, Oshima and Kitagawa (1961), Oshima (1962), and Minamori et al (1962Minamori et al ( , 1964 have analysed populations of Drosophila melanogaster in Japan and found them to be small, in some cases similar to Korean populations. Oshima et al (1961), however, suggested that the breeding unit in a majority of the Japanese populations is larger than that in Korean populations and they estimated the mean effective breeding unit to be about 1700 pairs of flies for the former and 300 for the latter.…”

FREQUENCY OF DELETERIOUS CHROMOSOMES AND ALLELISM BETWEEN LETHAL GENES IN JAPANESE NATURAL POPULATIONS OF <i>DROSOPHILA MELANOGASTER</i>

“…Oshima and Kitagawa (1961) analyzed the second chromosomes extracted from Suyama-Juriki natural populations under the Samarkand isogenic background. Minamori and Azuma (1962) isolated the second chromosomes from Hiroshima populations under an isogenic background derived from an inbred Hiroshima strain.…”