TY - JOUR
T1 - Replicated anthropogenic hybridisations reveal parallel patterns of admixture in marine mussels
AU - Simon, Alexis
AU - Arbiol, Christine
AU - Nielsen, Einar Eg
AU - Couteau, Jérôme
AU - Sussarellu, Rossana
AU - Burgeot, Thierry
AU - Bernard, Ismaël
AU - Coolen, Joop W.P.
AU - Lamy, Jean-Baptiste
AU - Robert, Stéphane
AU - Skazina, Maria
AU - Strelkov, Petr
AU - Queiroga, Henrique
AU - Cancio, Ibon
AU - Welch, John J.
AU - Viard, Frédérique
AU - Bierne, Nicolas
PY - 2020/3
Y1 - 2020/3
N2 - Human-mediated transport creates secondary contacts between genetically differenti-ated lineages, bringing new opportunities for gene exchange. When similar introductions occur in different places, they provide informally replicated experiments for studying hy-bridisation. We here examined 4,279 Mytilus mussels, sampled in Europe and genotyped with 77 ancestry-informative markers. We identified a type of introduced mussels, called “dock mussels,” associated with port habitats and displaying a particular genetic signal of admixture between M. edulis and the Mediterranean lineage of M. galloprovincialis. These mussels exhibit similarities in their ancestry compositions, regardless of the local native genetic backgrounds and the distance separating colonised ports. We observed fine-scale genetic shifts at the port entrance, at scales below natural dispersal distance. Such sharp clines do not fit with migration-selection tension zone models, and instead suggest habitat choice and early-stage adaptation to the port environment, possibly coupled with connec-tivity barriers. Variations in the spread and admixture patterns of dock mussels seem to be influenced by the local native genetic backgrounds encountered. We next examined de-partures from the average admixture rate at different loci, and compared human-mediated admixture events, to naturally admixed populations and experimental crosses. When the same M. galloprovincialis background was involved, positive correlations in the departures of loci across locations were found; but when different backgrounds were involved, no or negative correlations were observed. While some observed positive correlations might be best explained by a shared history and saltatory colonisation, others are likely produced by parallel selective events. Altogether, genome-wide effect of admixture seems repeat-able and more dependent on genetic background than environmental context. Our re-sults pave the way towards further genomic analyses of admixture, and monitoring of the spread of dock mussels both at large and at fine spacial scales.
AB - Human-mediated transport creates secondary contacts between genetically differenti-ated lineages, bringing new opportunities for gene exchange. When similar introductions occur in different places, they provide informally replicated experiments for studying hy-bridisation. We here examined 4,279 Mytilus mussels, sampled in Europe and genotyped with 77 ancestry-informative markers. We identified a type of introduced mussels, called “dock mussels,” associated with port habitats and displaying a particular genetic signal of admixture between M. edulis and the Mediterranean lineage of M. galloprovincialis. These mussels exhibit similarities in their ancestry compositions, regardless of the local native genetic backgrounds and the distance separating colonised ports. We observed fine-scale genetic shifts at the port entrance, at scales below natural dispersal distance. Such sharp clines do not fit with migration-selection tension zone models, and instead suggest habitat choice and early-stage adaptation to the port environment, possibly coupled with connec-tivity barriers. Variations in the spread and admixture patterns of dock mussels seem to be influenced by the local native genetic backgrounds encountered. We next examined de-partures from the average admixture rate at different loci, and compared human-mediated admixture events, to naturally admixed populations and experimental crosses. When the same M. galloprovincialis background was involved, positive correlations in the departures of loci across locations were found; but when different backgrounds were involved, no or negative correlations were observed. While some observed positive correlations might be best explained by a shared history and saltatory colonisation, others are likely produced by parallel selective events. Altogether, genome-wide effect of admixture seems repeat-able and more dependent on genetic background than environmental context. Our re-sults pave the way towards further genomic analyses of admixture, and monitoring of the spread of dock mussels both at large and at fine spacial scales.
KW - admixture
KW - bentho-pelagic species
KW - biological introductions
KW - clines
KW - ports
KW - secondary contact
U2 - 10.1111/eva.12879
DO - 10.1111/eva.12879
M3 - Article
VL - 13
SP - 575
EP - 599
JO - Evolutionary Applications
JF - Evolutionary Applications
SN - 1752-4563
IS - 3
ER -