Biology subjects

Fukutomi, Y.

Publications and source records attributed to Fukutomi, Y..

4 recordsLinked to original sources

bioRxiv2026

Interspecific differences in second-site modifiers reshape dominance in a Mendelian trait by altering environmental plasticity

Dominance is an important and evolvable property of the genotype-phenotype map. A longstanding debate in evolutionary genetics concerns whether dominance is determined primarily by intrinsic properties of alleles at the focal locus or by modifiers elsewhere in the genome. Theoretical models show that second-site modifiers of dominance can evolve under some conditions. However, direct empirical tests of these models are rare because they require holding the focal heterozygous genotype constant while changing the rest of the genome. In the Drosophila montium species subgroup, female pigmentation is a Mendelian trait controlled by a single gene, POU domain motif 3 (pdm3), but the dominance relationships between pdm3 alleles differ among species. Using reciprocal introgressions among three closely related species, we compared females carrying the same Light/Dark pdm3 allele combinations in different homozygous or heterozygous genomic backgrounds and across different temperatures. In both species-pair comparisons, changing genomic background significantly altered the phenotype of identical pdm3 heterozygotes, demonstrating the existence of second-site modifiers of dominance. The effects of dominance modifiers depend on the particular pair of pdm3 alleles and on rearing temperature. These results show that dominance in this system is a genotype-by-genotype-by-environment trait, rather than a fixed attribute of individual alleles. The finding that second-site modifiers can alter dominance by reshaping reaction norms provides a developmental mechanism that links the evolution of dominance to phenotypic plasticity.

evolutionary biology↗

bioRxiv2025

Evolution of dominance in a Mendelian trait is linked to the evolution of environmental plasticity.

Allelic dominance and phenotypic plasticity both influence how genetic variation is expressed in phenotypes, shaping evolutionary responses to selection. In both cases, changes in genotype or environment can cause sharp, nonlinear phenotypic shifts, hinting at shared underlying features of development that may link dominance and plasticity. Here, we investigate these links using a Mendelian, female-limited color dimorphism found in many species of the Drosophila montium lineage. In most species, the Dark allele is dominant, but two species--D. jambulina and D. cf. bocqueti--have been reported to have dominant Light alleles. We show that in both Dark-dominant and Light-dominant species, the color dimorphism is linked to the same locus: the POU domain motif 3 (pdm3) transcription factor. We then demonstrate that the interspecific differences in dominance relationships between pdm3 alleles are due to changes in phenotypic plasticity. In the Dark-dominant species D. rufa and D. burlai, the Dark allele is dominant across all developmental temperatures. In contrast, in both Light-dominant species, dominance is temperature-dependent, with the Light allele becoming increasingly dominant at higher temperatures. These results suggest a mechanistic connection between the evolution of dominance and phenotypic plasticity. We propose this connection may emerge from threshold-like properties of developmental systems. Teaser textThis study reveals a direct relationship between the evolution of dominance and phenotypic plasticity in a Mendelian, female-limited color dimorphism. This trait is linked to the same transcription factor gene, pdm3, in multiple species of the Drosophila montium lineage. However in some species, the Light pdm3 allele becomes increasingly dominant at higher temperature, while in others the Dark allele is fully dominant under all conditions. Based on these results, we propose that the evolution of dominance and plasticity may be connected by threshold-like properties of developmental systems.

evolutionary biology↗

bioRxiv2023

Thermal plasticity of wing spot size in Drosophila guttifera: investigating the relevance to Wingless morphogen

Thermal plasticity of animal color patterns has been studied to investigate the molecular mechanisms of phenotypic plasticity. There are examples in which the formation of color patterns is controlled by a morphogen. The extracellular distribution of a morphogen can be plastic with temperature change. Whether alteration of morphogen distribution with temperature change produces thermal plasticity in color patterns has not been studied. To address this question, polka-dotted wing spots of Drosophila guttifera, whose inducer is wingless morphogen, can be a suitable model system. In this study, we reared D. guttifera at different temperatures to test whether wing spots show thermal plasticity. We found that wing size becomes larger and spot size adjusted with wing size becomes smaller at lower temperatures. We also changed the rearing temperature in the middle of the pupal period and found that the most sensitive developmental period for wing size and spot size is different. The results suggest that developmental mechanisms for the thermal plasticity of wing size and spot size are different. We also found that the most sensitive stage for spot size was part of the pupal period including stages at which wingless is expressed in the polka-dotted pattern. Therefore, it is suggested that temperature change might affect the process of specifying spot areas by Wingless in the extracellular region.

zoology↗

bioRxiv2020

Transcriptome analysis reveals evolutionary co-option of neural development and signaling genes for the wing pigmentation pattern of the polka-dotted fruit fly.

How evolutionary novelties have arisen is one of the central questions in evolutionary biology. Pre-existing gene regulatory networks or signaling pathways have been shown to be co-opted for building novel traits in several organisms. However, the structure of entire gene regulatory networks and evolutionary events of gene co-option for emergence of a novel trait are poorly understood. In this study, we used a novel wing pigmentation pattern of the polka-dotted fruit fly, and identified the complete set of genes for pigmentation pattern formation by de novo genome sequencing and transcriptome analyses. In pigmentation areas of wings, 151 genes were positively or negatively regulated by wingless, a master regulator of wing pigmentation. Genes for neural development, Wnt signaling, Dpp signaling, Zinc finger transcription factors, and effectors (such as enzymes) for melanin pigmentation were included among these 151 genes. None of the known regulatory genes that regulate pigmentation pattern formation in other fruit fly species were included. Our results suggest that the novel pigmentation pattern of the polka-dotted fruit fly emerged through multi-step co-options of multiple gene regulatory networks, signaling pathways, and effector genes, rather than recruitment of one large gene circuit.

developmental biology↗