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Contrasting genetic structures across two hybrid zones of a tropical reef fish, Acanthochromis polyacanthus (Bleeker 1855)
Author(s) -
VAN HERWERDEN L.,
DOHERTY P. J.
Publication year - 2006
Publication title -
journal of evolutionary biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.289
H-Index - 128
eISSN - 1420-9101
pISSN - 1010-061X
DOI - 10.1111/j.1420-9101.2005.00969.x
Subject(s) - biology , introgression , biological dispersal , hybrid zone , allopatric speciation , mitochondrial dna , hybrid , phylogeography , reproductive isolation , coral reef fish , ecology , gene flow , zoology , reef , genetic variation , population , phylogenetics , genetics , demography , botany , sociology , gene
Hybrid zones are natural laboratories offering insights into speciation processes. Narrow hybrid zones are less common in the sea than on land consistent with higher dispersal among marine populations. Acanthochromis polyacanthus is an unusual bony marine fish with philopatric dispersal that exists as allopatric stocks of white, bicoloured and black fish on the Great Barrier Reef (GBR). At two latitudes, different morphs coexist and hybridize at narrow contact zones. Sequence data from mitochondrial Hypervariable Region 1 revealed contrasting patterns of introgression across these zones. At the northern hybrid zone, a single clade of mitochondrial haplotypes was found in all white fish, hybrids and tens of kilometres into pure bicoloured stock. At the southern hybrid zone, there was no introgression of mitochondrial genes into black fish and hybrids shared the bicoloured haplotypes. Based on this asymmetry, we postulate that black fish from the southern GBR have experienced a selective sweep of their mitochondrial genome, which has resulted in almost total reproductive isolation.