Comparative evaluation of DNA isolation methods from porcine semen

Different biological samples require specific protocols for isolating DNA from them. Semen samples require special considerations because of the presence of protamines in place of histones in the DNA of spermatozoa. An experiment was conducted at the Institute Swine Production farm at ICAR-Indian Veterinary Research Institute, Bareilly, to select the best-suited DNA isolation protocol from porcine semen. Healthy Landrace boars from the farm were given preliminary training and 18 ejaculates were collected from them for the study. DNA isolation was done in three methods in order to standardize and finalize a protocol suitable for porcine semen. The methods were phenol-chloroform as described in Russel and Sambrook (2001) with slight modifications, Chelex-100 (Walsh et al., 2013) and using commercial kit method (Applied Biosystems). The genomic DNA isolated from the porcine semen samples were checked for quality, purity, and concentration. Among the three methods selected for DNA extraction, all gave apparently good quality DNA with purity in the preferred range of 1.8-2.0 but differed in the concentration according to the nanodrop reading. On analysing the results statistically, the modified Phenol-Choloroform technique showed significant variation in concentration of isolated DNA in comparison to the Chelex -100 method and commercial kit method.