Effect of founding events on coat colour polymorphism of Apodemus speciosus (Rodentia: Muridae) on the Izu islands

Morihiko Tomozawa, Mitsuo Nunome, Hitoshi Suzuki, Hirotake Ono

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)


To infer the evolutionary mechanism of phenotypic variation among isolated island populations, we investigated coat colour and genetic variation in the large Japanese field mouse (Apodemus speciosus) on the Izu Islands (Ohshima, Niijima, Kouzushima, and Miyakejima). Coat colour in the most remote population (Miyakejima) was unique and significantly darker than that in the other populations. Ohshima that is closest to the source population showed variation in coat colour within its population. Phylogeographical analyses using mitochondrial and microsatellite markers suggested that the island populations (except Kouzushima) were founded sequentially from the closest Ohshima to remote Niijima and Miyakejima during or before the penultimate interglacial period. Secondary gene flow from the source population was rare and occurred only for the closest (Ohshima) population. In addition, we found that an amino acid mutation in the Agouti signalling protein gene (Asip) was associated with coat colour variation among the island populations. The mutation was rare in the source population but completely fixed in the Miyakejima population. The phenotypic and genetic variation suggested that severe reduction of genetic variation and changes in allele frequency as a result of sequential colonization (i.e. the founder effect) had significant effects on colour polymorphism. The findings of the present study suggest that the founder effect, in addition to natural selection, facilitated the morphological changes below the species level over a relatively long time scale.

Original languageEnglish
Pages (from-to)522-535
Number of pages14
JournalBiological Journal of the Linnean Society
Issue number2
Publication statusPublished - 2014


  • Asip
  • Founder effect
  • Island archipelago
  • Phylogeography
  • Population history

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics


Dive into the research topics of 'Effect of founding events on coat colour polymorphism of Apodemus speciosus (Rodentia: Muridae) on the Izu islands'. Together they form a unique fingerprint.

Cite this