A new mutation in the timing of autogamy in Paramecium tetraurelia.
We have isolated a new type of Paramecium tetraurelia mutant, named rie-2, that has a long immaturity period until autogamy. We previously isolated such an autogamy mutant, designated rie-1. These two mutants had some additional common features such as dependence of the occurrence of autogamy on the temperature, involvement of a single recessive gene, lower fission rate and shorter clonal life span. However, rie-2 was considered a new type mutant distinguishable from rie-1 because of their different natures of temperature sensitivity. First, the temperature at which they resembled the wild-type phenotype was low (19 degrees C) in rie-2, although it was high (32 degrees C) in rie-1. Second, the clonal life span of rie-2 at 25 degrees C was similar to that of the wild-type, but it was extremely shorter at 32 degrees C than at 25 degrees C, although it was similarly shorter at both temperatures in rie-1. Third, the difference of the fission rate between mutant and wild-type was greater at 32 degrees C than at 25 degrees C in rie-2, although it was similar at both temperatures in rie-1. This report shows that a gene mutation to elongate the period until sexual maturation does not necessarily assure the long life span.
Komori
Rie
R
Department of Biological Science, Faculty of Science, Nara Women's University, Japan.
Sato
Hiroaki
H
Harumoto
Terue
T
Takagi
Yoshiomi
Y
D000818:Animals; D017125:Genes, Protozoan; D005808:Genes, Recessive; D008136:Longevity / Q000235:genetics*; D009154:Mutation; D016805:Paramecium tetraurelia / Q000235:genetics*; D012741:Sexual Maturation / Q000235:genetics