Evidence that Magnetic Navigation and Geomagnetic Imprinting Shape Spatial Genetic Variation in Sea Turtles

Abstract:

The canonical drivers of population genetic structure, or spatial genetic variation, are isolation by distance and isolation by environment. Isolation by distance pbkp_redicts that neighboring populations will be genetically similar and geographically distant populations will be genetically distinct [1]. Numerous examples also exist of isolation by environment, a phenomenon in which populations that inhabit similar environments (e.g., same elevation, temperature, or vegetation) are genetically similar even if they are distant, whereas populations that inhabit different environments are genetically distinct even when geographically close [2–4]. These dual models provide a widely accepted conceptual framework for understanding population structure [5–8]. Here, we present evidence for an additional, novel process that we call isolation by navigation, in which the navigational mechanism used by a long-distance migrant influences population structure independently of isolation by either distance or environment. Specifically, we investigated the population structure of loggerhead sea turtles (Caretta caretta) [9], which return to nest on their natal beaches by seeking out unique magnetic signatures along the coast—a behavior known as geomagnetic imprinting [10–12]. Results reveal that spatial variation in Earth's magnetic field strongly pbkp_redicts genetic differentiation between nesting beaches, even when environmental similarities and geographic proximity are taken into account. The findings provide genetic corroboration of geomagnetic imprinting [10, 13]. Moreover, they provide strong evidence that geomagnetic imprinting and magnetic navigation help shape the population structure of sea turtles and perhaps numerous other long-distance migrants that return to their natal areas to reproduce [13–17]. Brothers and Lohmann report a relationship between sea turtle population structure and Earth's magnetic field. Results provide genetic evidence that turtles accomplish natal homing via magnetic navigation, which can evidently mediate genetic differentiation independent of isolation by distance or environment.

Año de publicación:

2018

Keywords:

• geomagnetic imprinting
• magnetic navigation
• sea turtles
• Natal homing

Fuente:

scopus