Complex relationships between mitochondrial and nuclear DNA preservation in historical DNA extracts

‘Historical’ DNA obtained from specimens preserved in natural history collections has proven useful for addressing a wide variety of questions, such as the spread of domesticated species or changes in genetic diversity. With the development of high-throughput sequencing techniques, there is an increasing focus on acquiring genetic information encoded by single-copy nuclear DNA from historical DNA extracts. The development of efficient techniques to determine the level of nuclear DNA preservation in candidate specimens is necessary to maximize the data obtained from these analyses. Although current evidence suggests that a sample's mitochondrial DNA preservation predicts its nuclear DNA preservation, we show that the relationships between mitochondrial and nuclear DNA preservation are complex.