Method development and comparison for storage and extraction of peripheral blood DNA on Guthrie cards

Abstract

Traditionally, genetic testing for disorders such as β-thalassaemia, sickle cell disease, cystic fibrosis and many more involves DNA extraction from whole blood stored in ethylenediaminetetraacetic acid (EDTA) vacutainers followed by polymerase chain reaction (PCR) and sequencing. Another practice for the screening of metabolic and genetic disorders of newborn babies is the collection and blotting of small drops of blood samples spotted onto filter paper, also called Guthrie cards. These type of blood samples are an important resource for genomic research as well as archiving of certain clinically important samples. In this research, anonymous peripheral blood from purpled capped vacutainers was transferred to the Guthrie cards. The dried blood spots from the Guthrie Cards were then used as a sample to extract DNA and determine the best yield and quality of the dried blood that provides sufficient genomic DNA for genetic testing. The aim of this study was to collect blood on Guthrie cards, design an experiment and develop a method to extract DNA from blood stored on the Guthrie card and compare the quality and quantity of DNA obtained with that obtained from published literature. Furthermore, parameters such as temperature used for storage, age of the subject’s blood sample, and any relevant clinical conditions that may confound the results were noted (e.g., haemolytic anaemia). In this study the salting out technique was chosen and further modified to my project needs. The overall objective of this research, which was to determine whether these dried blood spot cards are able to serve as samples for DNA testing has been met. Meaning that DNA yielded was in good quantity and also in good quality. They offer a more practical approach to store samples intended for archiving since they take up significantly less space than the traditional tubes. These can facilitate stacking as well as easier for sample transport between laboratories or countries and biobanking of samples.