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Hybridization and introgression in a mixed population of the intertidal seaweeds Fucus evanescens and F. serratus
Author(s) -
COYER J. A.,
HOARAU G.,
STAM W. T.,
OLSEN J. L.
Publication year - 2007
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.1420-9101.2007.01411.x
Subject(s) - biology , introgression , hybrid , botany , backcrossing , population , chloroplast dna , fucus , hybrid zone , gene flow , genetics , algae , genetic variation , chloroplast , gene , demography , sociology
The introduced Fucus evanescens (hermaphroditic) and the native F. serratus (dioecious) have been in secondary contact along the Danish coast of the Kattegat Sea for 60–100 years and dioecious hybrids have been observed at Blushøj for several years. Hybridization in Fucus is unusual because it appears to always involve a hermaphroditic and a dioecious parental pair. We determined the degree and spatial patterns of introgression for 286 individuals using 10 microsatellite loci and cpDNA. Hybrids accounted for nearly 13% of the population, yet parental species were well differentiated ( F ST = 0.633). The presence of F. evanescens chloroplasts in 100% of F 1 hybrids revealed asymmetrical hybridization. Fucus evanescens cpDNA was observed in 50% of introgressed and 5.4% of pure F. serratus , but no F. serratus cpDNA was found in F. evanescens . In contrast, nuclear DNA introgression was symmetrical with an equal amount (≈1.5%) of genes introgressed into each parental species. Survivorship and viability data suggest selection against hybrids in the hybrid zone.