Evaluation of human DNA extraction from hair roots method

Abstract

Extraction of DNA from specimens is a required step which provides DNA for further studies in molecular genetics. Human genomic DNA can be obtained from several kinds of specimens. Blood is a prefer specimen as they provide adequate DNA. However, blood specimen not always easy to collect while other specimen like hair root is easier. Hair roots contain extremely small amount of DNA and it is difficult to extract DNA of sufficient quality and quantity which is normally required in human molecular genetic studies. This research is carried out to select an efficient DNA extraction method using hair root specimens. Totally 375 hair roots were collected from 45 volunteers and divided into 3 groups for evaluation of 2 extraction method. Each group of hair roots was used for extraction of DNA with two basic DNA extraction methods: phenol and salting out. Hair roots were collected and stored in different period time: fresh, 1 week and 1 month. The comparison will performed to evaluate the extraction method for each group based on the quantity and quality of DNA extracted. Quantity of DNA was measured by Nanodrop system. Quality of DNA was measured by the DNA bands on agarose gel and the product of a PCR assay. The phenol method is considered as a better method for extraction of DNA from hair roots which give a higher quantity and quality of DNA. Checking DNA extracted on agarose gel, the result showed that DNA extracted from phenol method also give the clearer bands compared to those from salting out method. PCR assay testing on DNA extracted showed the result that either salting out method or phenol method with the same amount of DNA in PCR assay they showed the clear PCR products on agarose gel. The phenol method is an efficient method for extraction of DNA from hair roots. 5 hair roots can be achieved in around 1µl of DNA which is enough for at least 10 PCR assays. Fresh hair root is recommended for extraction of DNA. However, hair roots stored in 1 week and 1 month are still sufficiency for extraction of DNA by phenol method.