Publication Title: 
Cronn, et al. (2021)
Range-wide assessment of a SNP panel for individualization and geolocalization of bigleaf maple (Acer macrophyllum Pursh)
Cronn, Richard, Kristen N. Finch, Laura L. Hauck, Meaghan Parker-Forney, Brook G. Milligan, Jenélle Dowling, Adventure Scientists
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Series Name: 
Forensic Science International: Animals and Environments
Illegal logging is a worldwide problem that degrades ecosystems, and even low-risk markets like the United States report ~1000 significant hardwood timber theft cases per year. Due to its high value, bigleaf maple (Acer macrophyllum Pursh) is a common target of timber theft in western North America. Using samples from Washington, USA, a single nucleotide polymorphism [SNP] assay was recently developed to facilitate timber poaching investigations in this species based on the single base extension Agena MassARRAY® genotyping system and 133 loci. Our study expands earlier evaluations to include the full 2,000 km latitudinal range of bigleaf maple, using 1,142 samples collected from California, USA to British Columbia, CAN. Populations in this study are equivalent to level 3 Ecoregions, with sample sizes ranging from 28 (California Coast) to 191 (Washington Coast). Wood-derived DNA concentrations between 0.24 – 6 ng/μl yielded SNP call rates > 92%, and variation within this range did not influence genotyping call rates. DNA from different tissues showed a weak but significant difference in call rate, with DNA from wood showing a slightly higher call rate than DNA from leaves (99.4% vs 97.9%, respectively). Analysis of 108 sample replicates showed that missing genotypes occurred at 0.165% of all loci, and that allelic drop-outs and drop-ins each occurred at 0.022% of all genotype calls. Population-specific genotype profile probabilities for Pacific Northwest Ecoregions were lower than 1.9 × 10-33; these values are higher (less powerful) in Californian trees due to lower variability across these SNPs. Conversely, the geographic origin of trees from Southern Californian Ecoregions could be predicted with lower error (8.5% - 11.7%) than trees from the Pacific Northwest (36% - 80%), based on random forest classification. This study provides a “case work-ready” database for forensic individualization of bigleaf maple across its complete range in western North America.
Publication Species: 
Acer macrophyllum (Bigleaf maple)
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