Evaluation of DNA degradation and establishment of a degradation analysis model for Lepidoptera specimens.

Millions of museum specimens are integral to biodiversity studies; however, DNA degradation may limit the ability to obtain DNA sequences. In this study, a degradation analysis model for Lepidoptera specimens was established. Based on this model, we revealed the characteristics of DNA fragment distribution caused by external DNA damage factors during specimen preservation. We found that the degree of DNA degradation increased over time; DNA degradation of spread and dried adult specimens was significantly higher than that in the folded and formalin-fixed larval specimens. However, the effects of folding wings on DNA degradation and the effects of the preservation method/stage (formalin-fixed larval vs air-dried adult specimens) were different for different species. METHOD SUMMARY Using one-way analysis of variance and the likelihood ratio test, the differences in DNA fragment distribution between different Lepidopteran specimens were analyzed. Based on the random-breakage model, a degradation analysis model for Lepidoptera specimens was established. Based on this model, this paper reveals the characteristics of DNA fragment distribution caused by external DNA damage factors during specimen preservation.