Novel molecular protocol for sex identification in the Adélie penguin. PNRA2016 Az. 1.11 “PenguinERA” project

Sex identification is crucial for behavioural, ecological and conservation studies. In monomorphic bird species, traditional methods for sex assessment often require invasive sampling and long manipulation of individuals through cloacal examination. Thus, molecular methods involving less invasive sampling are needed to reduce the stress of study animals. In monomorphic Adélie penguins Pygoscelis adeliae, we evaluated the use of a penguin-specific primer pair (PL/PR) to identify sex through DNA extracted from non-destructive samples, i.e. feathers. We also reported DNA extraction and detailed PCR protocols to improve amplification success. With these primers, we efficiently identified the sex of all sampled individuals (N = 92, belonging to 46 complete nesting pairs), with two distinct CHD1Z and CHD1W bands. Our results were also confirmed through Sanger sequencing. Our findings emphasised the effectiveness and reliability of molecular methods to identify sex of monomorphic birds through suitable protocols and non-destructive samples. The use of this sampling method should be therefore recommended for future studies to reduce stress in manipulated individuals.