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Extreme changes to gene expression associated with homoploid hybrid speciation
Author(s) -
HEGARTY MATTHEW J.,
BARKER GARY L.,
BRENNAN ADRIAN C.,
EDWARDS KEITH J.,
ABBOTT RICHARD J.,
HISCOCK SIMON J.
Publication year - 2009
Publication title -
molecular ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.619
H-Index - 225
eISSN - 1365-294X
pISSN - 0962-1083
DOI - 10.1111/j.1365-294x.2008.04054.x
Subject(s) - biology , allopatric speciation , hybrid , genetic algorithm , evolutionary biology , genetics , natural selection , botany , selection (genetic algorithm) , population , demography , artificial intelligence , sociology , computer science
Abstract Hybridization is an important cause of abrupt speciation. Hybrid speciation without a change in ploidy (homoploid hybrid speciation) is well‐established in plants but has also been reported in animals and fungi. A notable example of recent homoploid hybrid speciation is Senecio squalidus (Oxford ragwort), which originated in the UK in the 18th Century following introduction of hybrid material from a hybrid zone between S. chrysanthemifolius and S. aethnensis on Mount Etna, Sicily. To investigate genetic divergence between these taxa, we used complementary DNA microarrays to compare patterns of floral gene expression. These analyses revealed major differences in gene expression between the parent species and wild and resynthesized S. squalidus . Comparisons of gene expression between S. aethnensis , S. chrysanthemifolius and natural S. squalidus identified genes potentially involved in local environmental adaptation. The analysis also revealed non‐additive patterns of gene expression in the hybrid relative to its progenitors. These expression changes were more dramatic and widespread in resynthesized hybrids than in natural S. squalidus , suggesting that a unique expression pattern may have been fixed during the allopatric divergence of British S. squalidus . We speculate that hybridization‐induced gene‐expression change may provide an immediate source of novel phenotypic variation upon which selection can act to facilitate homoploid hybrid speciation in plants.