Effects of DNA Extraction Methods on Recovery, Degradation, and Loss

DNA recovered from forensic and ancient DNA (aDNA) sources is generally expected to be in low copy number and degraded in strand length. However, considering the following equation, it is important to realize that the exact amount of recoverable DNA from any source is unknown:

Net yield of DNA= Original amount – loss in sampling – loss in extraction/purification – loss due to amplification bias (e.g., due to PCR inhibitors)

This study’s first objectives include estimating: 1) the amount of DNA lost during DNA extraction and purification, and 2) the degree to which molecules are damaged as a result of the extraction method.

Learning objectives:

1. To illustrate that we do not know how much DNA is available from any given sources. Analysts can only know how much is retained through the process of its extraction and purification. With regards to highly compromised DNA sources, there may exist more DNA than is currently recognized.
2. To illustrate the influence of various DNA extraction methods on the quantity (i.e., concentration) and quality (i.e., strand length) of resulting DNA eluates.
3. To provide a better illustration of the nature of DNA loss from degraded and low concentration sources when utilizing commonly used silica-based extraction methods.