Overview
ISO 18074:2015 - Textiles: Identification of some animal fibres by DNA analysis method - Cashmere, wool, yak and their blends specifies a qualitative laboratory method to identify cashmere, wool and yak fibres (and their blends) using DNA analysis. The procedure relies on mitochondrial DNA extraction, PCR (polymerase chain reaction) amplification with species-specific primers and detection of the amplified constant-length fragments (typically by gel electrophoresis). The standard is intended for textile testing where microscopic identification is insufficient or ambiguous.
Key topics and technical requirements
- Scope: Qualitative identification of cashmere, wool and yak fibres and their blends using DNA-PCR techniques.
- Test principle: Extract mitochondrial DNA from fibre samples → purify → amplify target fragment with species-specific primers → detect amplification products to confirm species identity.
- Main test stages: Sampling, chipping/homogenization, DNA extraction, DNA purification, PCR amplification, electrophoretic detection and verification.
- Equipment & reagents: PCR instrument, heat block, centrifuge (≥14 000 g), microtubes, gel electrophoresis apparatus, UV illuminator, species-specific primers, nuclease-free water and standard chemical reagents.
- Verification & quality control: Positive and negative controls, amplification verification, and procedures to confirm no cross-contamination. Annexes provide guidance on amplification of constant-length fragments, additional purification, repeatability/reproducibility and practical application to textile products.
- Limitations & caution: High-temperature processing, heavy dyeing or aggressive finishes can damage mitochondrial DNA and impede amplification. Surface contamination (e.g., cashmere grease on wool) can affect results and may require microscopy cross-checks.
Applications and users
- Textile testing laboratories performing fibre composition verification and forensic fibre identification.
- Quality control teams in textile manufacturing and processing (cashmere, wool, yak products).
- Certification bodies and compliance laboratories verifying labelling and claims for animal fibre content.
- Customs and regulatory agencies handling provenance or mislabeling investigations in apparel and home textiles.
Practical benefits include higher specificity than purely microscopic methods for distinguishing closely related animal fibres and robust identification of blends when DNA is intact.
Related standards
- ISO 17751 - Microscopy-based identification of animal fibres (complementary method)
- ISO 3696 - Water for analytical laboratory use (reagent quality)
- ISO 8655-2 - Piston-operated volumetric apparatus (pipette performance)
- ISO/TC 38 - Technical committee responsible for textile standards
Keywords: ISO 18074, DNA analysis, cashmere identification, textile testing, PCR method, mitochondrial DNA, yak wool blends, gel electrophoresis.