Table 1.

Comparison of the key steps of gDNA extraction protocols from the three different starting materials

DNA isolation step	Starting material
	3.2 mm DBS	100 μl WB	0.5 g UC
1. DNA binding column	Silica-based	Silica-based	Silica-based
2. Use of carrier RNA*	Yes	Yes	No
3. Duration of lysis step	1 h	1 h	~12 h
4. Elution volume	60 μl	100 μl	1 ml
5. Solution used for elution	Nuclease free water	Nuclease free water	Nuclease free water

*Carrier RNA was added into the lysis buffer at manufacturer’s recommended concentrations (DBS: 0.01 μg/μl and WB: 0.005 μg/μl). DBS–dried blood spots; WB–whole blood; UC–umbilical cord.