Tsuyoshi Ito, D.Sc.
Assistant Professor, Department of Evolution and Phylogeny, Primate Research Institute, Kyoto University
I have a wide interest in natural history and biodiversity. Currently, I am focusing on the mechanisms and processes underlying morphological diversity in primates. Morphological evolution is not only caused as a response to selection but is also influenced by genetic drift and gene flow. The direction and magnitude of morphological evolution are constrained by genetic and developmental integrations. I strive to understand the whole picture of these evolutionary nature by combining morphometric, genomic, phylogenetic, biogeographic, and paleontological approaches. In particular, I study macaques to understand the subthemes discussed below.
Most of these studies are collaborative works with other research groups including University of the Ryukyus, Ryukoku University, Chulalongkorn University, the Systematics and Phylogeny section, Center for Human Evolution Modeling Research, and Department of Wildlife Science of PRI. Our research can be accomplished thanks to many contributors who collected and preserved specimens and to the funds granted by K-CONNEX (MEXT), KAKEN (JSPS; 11J00120, 15J00134), the Fujiwara Natural History Foundation, University of the Ryukyus, and Primate Research Institute, Kyoto University.
Evolution does not just involves the processes of speciation and divergence but is like a reticulation. Hybridization and genomic admixture provide a novel combination of genes in recombinant descendants, thereby potentially contributing to the novelty and diversity of phenotypes. I examine genome-wide markers (e.g., RAD-Seq) to understand how hybridization and genetic introgression proceed and how they influence morphology. This study originates from a general interest in evolution; however this study could also contribute to the monitoring of invasive species.
- Genomic admixture and morphological variations in the hybrids between invasive macaques and native Japanese macaques
- Genomic admixture and morphological variations in the natural hybrid zones of macaques in Southeast Asia
Modularity and evolvability
The direction and magnitude of evolution are constrained by genetic and developmental integrations. I apply geometric morphometric and quantitative genetic approaches to understand how the genetic and developmental integrations set limits on the direction of skull evolution and how the evolvability changed in primate evolution.
- Modularity and variability of the nasofacial complex in Japanese macaques
- Geographic variations of craniofacial integration and modularity in Japanese macaques
- The effects of hybridization on craniofacial integration and modularity in macaques
Phenotypic evolution can be caused by genotypic changes; however, the relationship between genotype and phenotype is not like one-to-one correspondence. A gene usually determines multiple traits (pleiotropy), whereas a trait is often caused by the expressions of multiple genes and/or by their interactions (epistasis). I combine association mapping and population/comparative genetics to understand the complex genotype–phenotype networks (multiple-to-multiple relationships) and to understand the genetic backgrounds of phenotypic diversifications.
- Admixture mapping of quantitative morphological traits using macaque hybrids
- Development of the semi-automatic method of quantifying head morphology using registration and geometric morphometrics
Phylogenetic and biogeographic diversity
Molecular data have elucidated the phylogenetic relationships of living taxa; however, these data usually cannot extend to extinct taxa with unavailable DNA. Fossils are the only evidence that directly demonstrate the locality and morphology of extinct organisms and are therefore essential for understanding the evolutionary and phylogeographic histories of the studied taxon. I combine molecular and morphometric data to reconstruct the systematics of living and extinct primates.
- Ecogeographic variations in the skulls of Asian primates (particularly macaques and langurs)
- Phylogenetic inference of living and extinct macaques based on molecular and morphological data
- Phylogenetic comparative approach to estimate the mode and tempo of primate skull evolution
- Quatitative/population genetic approach to estimate the factors on craniofacial diversity in Japanese macaques
Google Scholar Citations
We are in charge of the collection management of vertebrate (especially primate) specimens at Primate Research Institute, Kyoto University. I (like many naturalists) owe much to museum collections, which have been accumulated by many contributors. I would like to reciprocate by collecting and preserving specimens, including both morphological and molecular resources, for future generations.
- Open lecture at Primate Research Institute (Janualy 30th, 2016)
- Open lecture at Japan Monkey Centre (August 28th, 2016)
More about me
Activity database on education and research, Kyoto University
Kanrin 41-2, Inuuyama, Aichi 484-8506, Japan