The identification of plants used to make tapa artefacts: development of a reference DNA database and trial of non-destructive DNA extraction methods

Tapa (barkcloth) is a non-woven textile made from the inner bark of some plant species. Tapa manufacture was once widespread throughout the Pacific and tapa from the eighteenth and nineteenth century form part of Pacific collections in many museums. Here we examined the feasibility of DNA identification of the plants used to make tapa artefacts by developing and testing a DNA reference database of chloroplast trnL intron P6 loop sequences from many of the plant species used to make tapa, as well as other New Zealand textile plants. This database enabled identification to genus for most species but many species shared identical sequences. Despite the lack of species-level resolution, this technique will still aid with identifying the origins of tapa artefacts made from plants with restricted distributions, such as endemic New Zealand and Hawaiian Islands plants. A second aim was to test a number of DNA extraction methods, including non-destructive methods of interest to the heritage sector, on tapa samples. Only one of the non-destructive sampling methods produced amplifiable DNA. However, we did find variation in the success of the destructive methods tested, with the Qiagen DNeasy Plant Mini Kit having the highest success rate.