有殼アメーバの遺傳學

第I報 Arcella hemisphaericaとCentropyxis aculeataで得られた遺傳性の畸形殼

抄録

1) Two kinds of shell abnormalities, double-lobed and slitted, were obtained in old cultures of both Arcella hemisphaerica and Centropyxis aculeata. The phenotypes are similar to those previously described by Reynolds (1923) and Jollos (1924) in Arcella polypora.
2) The abnormalities were inherited only to a few of their progeny most of which were quite normal individuals.
3) It has been shown that the time (2 to 12 months) during which the progenitor of the clones had been kept in old culture favoring the appearance of the abnormal individuals, has nothing to do with the degree of inheritance of the characters in question.
4) Though the old cultures are liable to yield more shell abnormalities than the new ones, as found in Arcella polypora by previous investigators, it is somewhat doubtful whether the change is the enduring modification in Jollos' sense (1924, 1939).
5) The necessity has been pointed out in relation to enduring modification to make distinction between the mechanism of appearance of the new character and the mechanism of its inheritance.
6) There is no causal relation between the abnormality of the shell and the nuclear number in Arcella hemisphaerica.
7) In Arcella hemisphaerica, the nuclear number is heritable. The shell of the trinucleate line is larger than that of the binucleate line, the ratio being 1.24 to 1.00 in diameter.