Video taken under NMFS Permit #14809 and 22156
Dolphin Population Genomics
GOAL 1: genetic variation
Uncover genetic differences between coastal populations of bottlenose dolphins on the U.S. East Coast.
Goal 2: hypoxia adaptations
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Identify genes under selection for tolerance to deep-diving and hypoxia.
Goal 3: phylogenetics
Assess relationships between populations of bottlenose dolphins, including admixture and changes in effective population size.
goal 4: population structure
Assess stock delineation for effection conservation management of bottlenose dolphins.
Research Methods
Over the past two decades, Duke researchers have taken biopsy samples from bottlenose dolphins along the East Coast. The samples have been frozen and stored. Our research team has extracted nuclear DNA from these samples using next-generation sequencing techniques and we are now analyzing the resulting sequences. As seen above, our current research goals are focused around discovering adaptations to hypoxia and revealing fine details of population structure. As we conduct our analyses, we are continuing to collect samples from local bottlenose dolphins.
Check out the genomics analysis tools and software we use:
Current Findings
So far, we've identified three genetically distinct populations of bottlenose dolphins off the East Coast. In the map on the right, each pin indicates the location where a dolphin was sampled. The three colors represent the three different populations.
Through further research into these three populations, we have determined that the inshore (red) population mixed with the shelf (blue) population at some point in the past. On the right, you can see an evolutionary tree for the three populations. The arrow indicates the direction of the mixture. For a more detailed explanation of these results, see Magdalena Phillips's blog post here.
We have also analyzed the genetic differences between each of the populations. Here is a flowchart explaining the process for how we went from our genetic data to identifying candidate genes that may be related to how each population handles hypoxia. For more information, see Claire Huang's blog post here.