Our research goal is to understand the molecular mechanisms underlying the evolution of biodiversity. Although many genes important for animal development and behavior have been identified in model organisms, little is known about the molecular mechanisms underlying naturally occurring phenotypic variation important for adaptation and speciation in wild populations. Furthermore, little is known about how newly evolved alleles important for adaptation and speciation spread within natural populations. To understand these ecological and genetic mechanisms, we mainly use stickleback fishes as a model. Our research takes an integrative approach across diverse disciplines.
Our research takes an integrative approach across diverse disciplines. The first step is to conduct a detailed ecological survey of natural variation among stickleback populations collected from diverse environments. Next, we use genetic and genomic tools to study the genetic architecture of ecologically important phenotypic traits and also identify candidate genes responsible for adaptation and speciation. Then, we use transgenic and knockout approaches to study the detailed molecular and physiological functions of these candidate genes in vivo. Furthermore, we plan to use semi-natural ponds to get insight into how different alleles behave within natural populations.
Ishikawa A, Kabeya N, Ikeya K, Kakioka R, Cech JN, Osada N, Leal MC, Inoue J, Kume M, Toyoda A, Tezuka A, Nagano AJ, Yamasaki YY, Suzuki Y, Kokita T, Takahashi H, Lucek K, Marques D, Takehana Y, Naruse K, Mori S, Monroig O, Ladd N, Schubert CJ, Matthews B, Peichel CL, Seehausen O, Yoshizaki G, Kitano J. A key metabolic gene for recurrent freshwater colonization and radiation in fishes. Science. 2019 May 31;364(6443):886-889.
Yoshida K, Ishikawa A, Toyoda A, Shigenobu S, Fujiyama A, Kitano J. Functional divergence of a heterochromatin-binding protein during stickleback speciation. Mol Ecol. 2019 Mar;28(6):1563-1578.
Ravinet M, Yoshida K, Shigenobu S, Toyoda A, Fujiyama A, Kitano J. The genomic landscape at a late stage of stickleback speciation: High genomic divergence interspersed by small localized regions of introgression. PLoS Genet. 2018 May 23;14(5):e1007358.
Ishikawa A, Kusakabe M, Yoshida K, Ravinet M, Makino T, Toyoda A, Fujiyama A, Kitano J. Different contributions of local- and distant-regulatory changes to transcriptome divergence between stickleback ecotypes. Evolution. 2017 Mar;71(3):565-581.