Barcoding for diatoms in the Yangtze River from the morphological observation and 18S rDNA polymorphic analysis

Area of Science:

• Forensic Science
• Microbiology
• Genetics

Background:

• Diatom determination is crucial in forensic science for estimating post-mortem interval, cause of death, and drowning site location.
• Morphological identification of diatoms beyond the genus level is challenging and requires specialized expertise.
• DNA barcoding has emerged as a powerful tool for accurate diatom taxa identification.

Purpose of the Study:

• To establish a comprehensive morphological and DNA barcoding profile for diatoms in the Nanjing section of the Yangtze River.
• To evaluate the utility of DNA barcoding for species-level diatom identification in forensic contexts.
• To provide a foundational dataset for future forensic applications utilizing diatoms.

Main Methods:

• Diatom morphological analysis using optical and electron microscopy across 10 water areas.
• Classification of diatoms to the genus level based on morphology.
• Design and analysis of 18S ribosomal DNA (rDNA) sequences as DNA barcodes at the species level.

Main Results:

• Morphological analysis successfully classified diatoms to the genus level.
• 18S rDNA sequences were analyzed as DNA barcodes, enabling species-level identification.
• The study successfully created the first morphological and DNA barcoding profiles for diatoms in this specific river section.

Conclusions:

• Detailed analysis of diatom DNA barcodes is a valuable tool for forensic applications.
• The established profiles significantly enhance the use of diatoms in forensic investigations.
• DNA barcoding provides a more precise and efficient method for diatom identification compared to traditional morphology.