Preparation of genetic samples

Understanding the genetic population structure in cetaceans provides insight into their biology and behaviour over both the long-term evolutionary and short-time scale. Such knowledge is important for conservation and management strategies because, while bottlenose dolphin enjoy a wide distribution at species level, there are survival challenges at population and group levels. A clear advantage of genetic studies over other methods is that they are generally straightforward, and can provide detailed information at the individual, population and species level. However, cryptic marine mammals, such as the bottlenose dolphin, are not easily accessible for sampling. Hence, samples are often obtained from a stranded animal, whose origin may be biased by post-mortem drift. Advances in different non- or minimal-invasive sampling (skin-swabbing, face and slough skin collection, biopsies) of living individuals in recent years has overcome some of the issues. Apart from genetic and gender analyses such samples may also give valuable insight into diet patterns and contaminant levels. Genetic analysis allows for population delineation as well as studying fitness related aspects. This is critical to identification of the appropriate level for application of conservation or management measures. We focus on applying a holistic genetic approach for available samples to infer population structure of the bottlenose dolphin in the Croatian Adriatic Sea. In particular, we employ two neutral marker systems:

  • the control region of mitochondrial DNA (mtDNA),
  • 12 variable microsatellites
  • the non-neutral MHC class II DQB region of exon 2.

In total 53 tissue samples, obtained from bottlenose dolphins were isolated and analysed so far. Of these, 39 samples originated from stranded individuals (2000-2008), while 14 were obtained through biopsy sampling from live animals in 2008. Resulting from these analyses that are two scientific papers now available