Animal STR testing remains essential, but standardization gaps persist
Bottom line
CURRENT BRIEF VERSION: A new review in Animals argues that short tandem repeat, or STR, analysis remains central to animal DNA work, but the field still faces persistent technical and operational hurdles compared with human forensic genetics. The paper by Aleksandra Figura and Magdalena Gryzińska highlights STR use across animal identification, parentage verification, biodiversity monitoring, wildlife forensic work, and food authentication, noting that these methods grew out of older RFLP approaches and remain widely used because they offer high sensitivity, strong discriminatory power, and multiplex testing. At the same time, the review points to recurring problems such as species-specific marker development, limited reference databases, inconsistent standardization and nomenclature, PCR artefacts including stutter and allelic imbalance, low-quality or low-quantity samples, and the added complexity of mixed or degraded material. Those concerns line up with broader literature showing that STRs are still the main markers used in animal forensics, even as laboratories test SNP-based, sequence-based STR typing, integrated SNPSTR systems, and other sequencing-based alternatives for harder samples. (pmc.ncbi.nlm.nih.gov)
Why it matters: For veterinary professionals, especially those connected to diagnostic labs, breeding programs, shelter medicine, conservation work, or legal case support, the review is a reminder that animal DNA results can be highly useful, but only as strong as the assay design, validation, population data, and interpretation framework behind them. Inter-laboratory testing has shown that low-template samples can still derail correct identification and parentage calls, and standards groups continue to push for stronger quality systems, proficiency testing, more harmonized marker panels, and clearer nomenclature. ISAG’s current comparison testing also shows the field is still actively refining both STR and SNP workflows rather than settling on a single universal approach. (pmc.ncbi.nlm.nih.gov)
What to watch: Expect more attention on standardized panels, forensic-quality validation, bioinformatic support, and gradual movement toward complementary SNP, MPS/NGS, or sequence-based methods where STR performance is limited, especially for degraded or complex samples. (pmc.ncbi.nlm.nih.gov)
Key facts
- Article type
- Review
- Journal
- Animals
- Authors
- Aleksandra Figura and Magdalena Gryzińska
- Main topic
- Short tandem repeat, or STR, analysis in animal DNA work
- Core uses
- Animal identification, parentage verification, biodiversity monitoring, wildlife forensic work, and food authentication
- Main limitation
- Animal DNA analysis is less mature than human forensic genetics, with fragmented methods, databases, validation practices, and nomenclature
- Technical challenges
- Species-specific marker development, limited reference databases, PCR artefacts, low-quality or low-quantity samples, and mixed or degraded material
- Methods under evaluation
- SNP-based, sequence-based STR typing, integrated SNPSTR systems, and other sequencing-based alternatives
CURRENT FULL VERSION: A new review in Animals puts a spotlight on a familiar but still unsettled part of veterinary and animal genetics: short tandem repeat analysis. Figura and Gryzińska describe STRs as a core tool for identifying animals, confirming parentage, tracking biodiversity, supporting wildlife investigations, and authenticating food products, but they also make the case that animal DNA analysis remains less mature than the human forensic field, with more fragmentation in methods, databases, validation practices, and nomenclature systems. The authors also place STRs in a longer technical arc, noting that animal DNA identification moved from older RFLP methods to STR analysis, which became widely adopted because of its sensitivity, discriminatory power, and ability to be multiplexed. (pmc.ncbi.nlm.nih.gov)
That gap has been building for years. Reviews of domestic animal and wildlife forensic genetics have repeatedly described STRs as the workhorse markers for non-human identification, while also noting that animal casework has had to evolve in the shadow of better-funded, more standardized human DNA systems. A 2024 Nature Reviews Genetics article called STRs the primary markers of forensic genetics more broadly, underscoring why they remain so important even as newer genomic tools emerge. (onlinelibrary.wiley.com)
The practical problems are well known, and they appear to be exactly the issues this Animals review is trying to synthesize. Animal STR testing often requires species-specific marker selection, careful allele nomenclature, and population databases that may be thin or uneven depending on species and geography. Sample quality is another major constraint: hair shafts, trace biological material, and degraded wildlife samples may not yield enough nuclear DNA for reliable STR profiling. In parentage and identity work, laboratories also have to deal with mutation, null alleles, PCR artefacts, stutter formation, allelic imbalance, and platform-to-platform differences that can complicate interpretation, especially with low-template DNA or mixed samples. (sciencedirect.com)
Recent inter-laboratory evidence shows these aren’t abstract concerns. In an animal forensic comparison study, low DNA template concentrations of 300 pg/µL or less were a significant barrier to correct identification and parentage results across participating laboratories. At the same time, ISAG continues to maintain recommended canine STR marker sets for parentage and identification, and its 2026-2027 forensic comparison testing allows laboratories to enter STR-only, SNP-only, or combined testing tracks, a sign that the field is actively benchmarking multiple technologies rather than moving away from STRs outright. (pmc.ncbi.nlm.nih.gov)
The review also points to where the field may be heading next. Rather than treating STRs and newer methods as competitors, it describes recent gains from massively parallel sequencing and next-generation sequencing, including sequence-based STR typing and integrated SNPSTR systems that can improve interpretation of complex or degraded samples. That matters in animal work, where case material is often limited, environmentally damaged, or taxonomically diverse. But the paper’s bottom line is not that STRs are obsolete. It is that they remain valuable across forensic analysis, conservation genetics, and efforts to combat illegal wildlife trade, provided the surrounding marker design, interpretation rules, and data infrastructure keep improving. (pmc.ncbi.nlm.nih.gov)
Industry and standards discussions point in the same direction. A recent review on standards in wildlife forensic science said accredited labs still generally work under ISO/IEC 17025, while also noting that OSAC standards for non-human STR panel development, interpretation without allelic ladders, and validation of multilocus databases are in preparation. Another recent review argued that, despite the lack of universal ISO standards specific to wildlife forensics, there is a growing ecosystem of guidance from SWFS, ENFSI-APST, and related groups. In other words, the technical community appears aligned on the problems, even if implementation still varies by species and laboratory setting. (pmc.ncbi.nlm.nih.gov)
Why it matters: For veterinary professionals, this is less about a niche forensic debate and more about the reliability of DNA-based decisions that can affect breeding records, legal disputes, conservation enforcement, shelter or rescue investigations, and, in some settings, diagnostic interpretation. A result labeled “genetic identification” can sound definitive to pet parents, courts, or regulators, but the underlying confidence depends on validation, marker choice, the strength of the comparison database, and the quality of the interpretation pipeline. That makes laboratory transparency, chain-of-custody discipline, and cautious interpretation especially important when veterinarians are asked to collect samples, explain reports, or support casework. (pmc.ncbi.nlm.nih.gov)
The bigger strategic question is whether STRs will remain dominant or become one tool in a broader toolkit. For now, the evidence suggests STRs are still the operational backbone of animal identification because they are familiar, established, and workable on existing forensic platforms. But newer SNP and sequencing approaches are gaining ground where STRs struggle, particularly in degraded samples, species discrimination, and higher-resolution analysis. That likely means the next phase won’t be replacement so much as layering: validated STR workflows for routine use, with SNP, sequence-based STR, SNPSTR, or broader MPS/NGS methods added where the case demands more sensitivity or specificity. (isag.us)
What to watch: Watch for follow-on work that turns broad concerns into species-specific guidance, plus new standards from ISAG and OSAC on marker panels, nomenclature, and validation, along with more bioinformatic support for interpreting complex profiles over the next one to two years. (pmc.ncbi.nlm.nih.gov)