Genetic assimilation and the postcolonization erosion of phenotypic plasticity in Island tiger snakes

Fabien Aubret*, Richard Shine

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

78 Citations (Scopus)

Abstract

In 1942, C.H. Waddington [1] suggested that colonizing populations could initially succeed by flexibly altering their characteristics (phenotypic plasticity; [2-4]) in fitness-inducing traits, but selective forces would rapidly eliminate that plasticity to result in a canalized trait [1, 5, 6]. Waddington termed this process "genetic assimilation" [1, 7]. Despite the potential importance of genetic assimilation to evolutionary changes in founder populations [8-10], empirical evidence on this topic is rare, possibly because it happens on short timescales and is therefore difficult to detect except under unusual circumstances [11, 12]. We exploited a mosaic of snake populations isolated (or introduced) on islands from less than 30 years ago to more than 9000 years ago and exposed to selection for increased head size (i.e., ability to ingest large prey [13-16]). Here we show that a larger head size is achieved by plasticity in "young" populations and by genetic canalization in "older" populations. Island tiger snakes (Notechis scutatus) thus show clear empirical evidence of genetic assimilation, with the elaboration of an adaptive trait shifting from phenotypically plastic expression through to canalization within a few thousand years.

Original languageEnglish
Pages (from-to)1932-1936
Number of pages5
JournalCurrent Biology
Volume19
Issue number22
DOIs
Publication statusPublished - 1 Dec 2009
Externally publishedYes

Keywords

  • EVO_ECOL

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