DNA methylation is done by adding methyl groups to the DNA molecule, changing the activity of a DNA segment without change in sequence. Bisulfite treatment is done before sequencing which yields information about the methylation status.
Advantages of Whole Exome Sequencing
Sample preparation follows the following steps:
Nucleic acid extraction-Nucleic acids (DNA or RNA) are extracted from a variety of biological samples like blood, cultured cells, tissue selections or urine .
Library preparation- the nucleic acids are converted into appropriate format according to the sequencing to be done by fragmentation and attachment of adapters .
Amplification- Amplification becomes essential to obtain enough coverage for reliable sequencing for samples with small amounts of starting material.
Polymerase chain reaction (PCR) is a common method to increase the amount of DNA.
Purification and quality control- This step is done for removal of unwanted material hindering sequencing. The quality and quantity of DNA improves the confidence of sequencing data.