1. Development of FTIR spectral library for the identification of Asian elephant ivory: an innovative approach in wildlife forensics.
- Author
-
Ann Jose, Shinta, Thiyagarajan, Kalaiyarasan Boopathy, Ganesan, Subhashree, Chandrasekaran, Bala Amarnath, Baskar, Chanthini, Singh, Rajinder, Kumari, Dhayanithi Vasantha, Ganesan, M.G., and Udhayan, A.
- Abstract
The illegal ivory trade remains a prime threat to elephant populations. Identification of ivory is crucial for combating illicit ivory trading. Studies have demonstrated that FTIR spectroscopy is one of the most suitable techniques for identifying ivory and its products. However, this technique could not have been fully utilized due to the lack of a reference IR spectral library/database. In light of this, the present study aimed to develop the FTIR spectral library for Asian elephant ivory. We collected eight Asian elephant ivory (n = 8) samples from our institute repository and recorded the FTIR spectrum. Further, based on the biochemical composition of ivory, we identified various characteristics, functional groups, and their respective wavenumbers. Furthermore, we used the FTIR spectrum of Asian elephant ivory as a reference to identify the fifteen carvings (n = 15) suspected to be of Asian elephant ivory. The results revealed that samples 1 -13 are visibly identical to the FTIR spectrum of Asian elephant ivory; in contrast, samples 14 and 15 do not match the FTIR spectrum of Asian elephant ivory. Hence, it is confirmed that out of fifteen samples, thirteen are likely to be of Asian elephant ivory origin. To confirm this finding, we employed the PLS-DA analysis. The result showed an R Square value of 0.9 for calibration and 0.75 for validation, and the model exhibited 100% accuracy in classifying the original and fake ivory samples. The results confirmed that FTIR combined with chemometrics analysis was useful for identifying ivory and fake materials. To validate the FTIR results, we extracted the DNA from suspected samples 1–15 and amplified elephant-specific D-loop and Sry (sex-determining region on the Y chromosome) genes. Subsequently, the PCR amplicons were examined on a 2.5% agarose gel and observed for samples 1–13, one band at 137 bp (for D-loop) and another at 97 bp (for Sry). These results indicated that samples 1–13 are of elephant origin, whereas samples 14 and 15 are not of elephant origin. To confirm this finding, the PCR amplicons (D-loop) from nine samples (1–9) were sequenced, and % similarity was analyzed. The results showed 96.6 to 100% similarity to the Mammuthus primigenius, Elephas maximus indicus, and Loxodonta africana. The primers (D-loop and Sry) used in this study are elephant-specific and do not distinguish the elephant species. Overall, DNA-based results supported the results from FTIR analysis and confirmed that the suspected samples 1–13 are of elephant origin and 14 and 15 are not of elephant origin. The current study has demonstrated the identification of ivory substitutes through FTIR spectral library for Asian elephant ivory, which is rapid, cost-effective, and has excellent potential for forensic analysis.Article Highlights: The FTIR spectral library was developed for Asian elephant ivory. The suspected elephant carvings were identified using the FTIR spectral library of Asian elephant ivory. The FTIR results were confirmed through PCR amplification of elephant-specific D-loop and Sry genes. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF