Evaluation of DNA yield from various tissue and sampling sources for use in single nucleotide polymorphism panels

R code to test for differences in DNA yield from of eight sample categories to gain insights into which provided adequate DNA to be used in ddRADseq or already developed SNP panels. We calculated mean, median and standard deviation with package psych using the describe() function. Additionally, we generated boxplots using package ggplot2 where the quantity for each tissue sample is categorized by storage or preservative. We fit linear mixed-effects models using package lme4 after selecting 5 covariates that have been considered to influence DNA yield from previous research that include: 1) tissue - blood, ear, RLN, muscle, nasal mucosa, and tongue; 2) preservative - Allflex, dried, ethanol, K2-EDTA, and none; 3) storage - frozen (−20°C), refrigerated, and room temperature; 4) pre-extraction - time (in days) in storage until DNA extraction; 5) post-extraction - time (in days) in storage after DNA extraction.