TY - JOUR
T1 - Genetic assimilation and the postcolonization erosion of phenotypic plasticity in Island tiger snakes
AU - Aubret, Fabien
AU - Shine, Richard
PY - 2009/12/1
Y1 - 2009/12/1
N2 - 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.
AB - 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.
KW - EVO_ECOL
UR - http://www.scopus.com/inward/record.url?scp=70450240766&partnerID=8YFLogxK
U2 - 10.1016/j.cub.2009.09.061
DO - 10.1016/j.cub.2009.09.061
M3 - Article
C2 - 19879141
AN - SCOPUS:70450240766
VL - 19
SP - 1932
EP - 1936
JO - Current Biology
JF - Current Biology
SN - 0960-9822
IS - 22
ER -