The DNA quality is one of the main conditioning factors for the individual identification. Therefore, appropriate methodologies are required for their extraction. A new DNA extraction method from sheep blood was implemented based on the hexadecyl trimethyl ammonium bromide method (CTAB 2%), 1) temperature changes, cell lysis and variation of washes (CTABM), and 2) addition of an incubation process with bacterial lysozyme (CTABML). The absorbance A280/260 and A260/230 nm was verified and DNA concentration was quantified. Markers for the constitutive Leptin and IGF-1 genes were amplified by PCR at the end point and visualized by electrophoresis in 2% agarose gel. Amplicons for both genes were sequenced, trimmed and assembled successfully. The modified methods had significant effect on the results. The average concentration of total DNA from blood was 73 ± 2.05 μg for CTABM and 284.43 ± 3.6 μg for CTABML. The absorbance in CTABM were 1.3 ± 0.182 and 0.5 ± 0.071, and with CTABML were 1.83 ± 0.091 and 1.75 ± 0.242, respectively. CTABML generated greater availability of DNA, ensuring the availability of genetic material of optimum quality and integrity to be used in subsequent specific test, being a reliable alternative in the extraction of DNA.

Keywords: CTAB, DNA extraction, lysozyme, blood