Kazuo H Takahashi

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BACKGROUND Progression of development has to be insulated from the damaging impacts of environmental and genetic perturbations to produce highly predictable phenotypes. Molecular chaperones, such as the heat shock proteins (HSPs), are known to buffer various environmental stresses, and are deeply involved in protein homeostasis. These characteristics of(More)
Cryptic genetic variation (CGV) or a standing genetic variation that is not ordinarily expressed as a phenotype is released when the robustness of organisms is impaired under environmental or genetic perturbations. Evolutionary capacitors modulate the amount of genetic variation exposed to natural selection and hidden cryptically; they have a fundamental(More)
Environmental canalization is defined as a reduction in the effect of external environmental perturbations on a phenotype, while phenotypic plasticity is defined as the production of different phenotypes in alternative environments. These terms describe different aspects of the same phenomenon, that is, the sensitivity of the phenotype to the environment.(More)
Fluctuating asymmetry (FA), defined as random deviation from perfect symmetry, has been used to assay the inability of individuals to buffer their developmental processes from environmental perturbations (i.e., developmental instability). In this study, we aimed to characterize the natural genetic variation in FA of wing shape in Drosophila melanogaster,(More)
Biological clocks regulate various behavioural and physiological traits; slower circadian clocks are expected to slow down the development, suggesting a potential genetic correlation between the developmental period and circadian rhythm. However, a correlation between natural genetic variations in the developmental period and circadian rhythm has only been(More)
Developmental processes of organisms are programmed to proceed in a finely regulated manner and finish within a certain period of time depending on the ambient environmental conditions. Therefore, variation in the developmental period under controlled genetic and environmental conditions indicates innate instability of the developmental process. In this(More)
Sexual size dimorphism (SSD), a difference in body size between sexes, is common in many taxa. In insects, females are larger than males in >70% of all taxa in most orders. The fruit fly, Drosophila melanogaster is one prominent model organism to investigate SSD since its clear and representative female-biased SSD and its growth regulation are well studied.(More)
Developmental stability is the tendency of morphological traits to resist the effects of developmental noise, and is commonly evaluated by examining fluctuating asymmetry (FA)-random deviations from perfect bilateral symmetry. Molecular mechanisms that control FA have been a long-standing topic of debate in the field of evolutionary biology and quantitative(More)
Hsp70 genes may influence the expression of wing abnormalities in Drosophila melanogaster but their effects on variability in quantitative characters and developmental instability are unclear. In this study, we focused on one of the six Hsp70 genes, Hsp70Ba, and investigated its effects on within- and among-individual variability in orbital bristle number,(More)
Developmental stability, the ability of organisms to buffer their developmental processes against developmental noise is often evaluated with fluctuating asymmetry (FA). Natural genetic variation in FA has been investigated using Drosophila wings as a model system and the recent estimation of the heritability of wing shape FA was as large as 20 %. Because(More)