Genetic patchiness in European eel adults evidenced by molecular genetics and population dynamics modelling.
Disentangling the demographic processes that determine the genetic structure of a given species is a fundamental question in conservation and management. In the present study, the population structure of the European eel was examined with a multidisciplinary approach combining the fields of molecular genetics and population dynamics modelling. First, we analyzed a total of 346 adult specimens of known age collected in three separate sample sites using a large panel of 22 EST-linked microsatellite loci. Second, we developed a European eel-specific model to unravel the demographic mechanisms that can produce the level of genetic differentiation estimated by molecular markers. This is the first study that reveals a pattern of genetic patchiness in maturing adults of the European eel. A highly significant genetic differentiation was observed among samples that did not follow an Isolation-by-Distance or Isolation-by-Time pattern. The observation of genetic patchiness in adults is likely to result from a limited parental contribution to each spawning event as suggested by our modelling approach. The value of genetic differentiation found is predicted by the model when reproduction occurs in a limited number of spawning events isolated from each other in time or space, with an average of 130-375 breeders in each spawning event. Unpredictability in spawning success may have important consequences for the life-history evolution of the European eel, including a bet-hedging strategy (distributing reproductive efforts over time) which could in turn guarantee successful reproduction of some adults.
Dipartimento di Biologia, Università di Padova, Padova, Italy. martipujolar@gmail.com
José Martin
JM
Pujolar
Daniele
D
Bevacqua
Marco
M
Andrello
Fabrizio
F
Capoccioni
Eleonora
E
Ciccotti
Giulio A
GA
De Leo
Lorenzo
L
Zane
D000811:Anguilla / Q000235:genetics* / Q000502:physiology; D000818:Animals; D014644:Genetic Variation; D005828:Genetics, Population; D018895:Microsatellite Repeats; D008957:Models, Genetic; D011157:Population Dynamics; D012098:Reproduction / Q000235:genetics