Fig 1.
TapeStation reports of DNA extracts from frozen blood.
TapeStation reports confirming high molecular weight of DNA extracts from frozen blood.
Fig 2.
Relationship between storage time of nucleated blood samples on FTA elute cards and DNA fragment length.
There is a non-significant negative influence of storage time on fragment length (N = 15, p = 0.221).
Fig 3.
TapeStation reports of DNA extracts from FTA elute cards.
TapeStation reports of DNA extracts from FTA elute cards stored for one year (A) and ten years (B) at room temperature. The mean fragment sizes are 16 and 15 kb.
Fig 4.
FastQC plot of filtered and trimmed samples from frozen blood (N = 25) and blood stored on FTA elute cards (N = 61). Reads of both sample types were of high quality (Phred score > 30).
Fig 5.
Read count across read position.
Read count across read position of R1 (A) and R2 (B) of all 86 samples (25 frozen blood and 61 FTA elute cards). Please note that the maximum value of the y-axis is different between the two panels.
Fig 6.
Distribution of methylation levels by sample type.
The boxplot shows the distribution of DNA methylation levels in samples collected using FTA cards (N = 61) and frozen samples (N = 25). Each box represents the interquartile range (IQR) with the median indicated by the horizontal black line inside the box and the median values in numbers just above the line. The whiskers extend to the most extreme data points within 1.5 times the IQR from the quartiles. FTA card samples are coloured in light blue and frozen samples in dark blue. A Welch’s t-test showed no statistically significant difference between the two groups (p > 0.05).
Table 1.
Alternative DNA extraction protocols trialed.