bisulfiittisekvenointia

Bisulfiittisekvenointia, or bisulfite sequencing, is a molecular biology technique used to determine the methylation status of DNA. Methylation is a key epigenetic modification where a methyl group is added to a cytosine base, typically in a CpG dinucleotide. This modification can affect gene expression without altering the underlying DNA sequence.

The process begins with treating DNA with sodium bisulfite. This chemical reaction deaminates unmethylated cytosines to uracils, while methylated cytosines remain unchanged. Following the bisulfite treatment, the DNA is typically amplified using polymerase chain reaction (PCR) and then sequenced. By comparing the obtained sequence to an unmethylated reference sequence, researchers can identify which cytosines were methylated. If a position that should be a cytosine in the reference is a thymine in the sequenced DNA, it indicates that the original cytosine was methylated and therefore protected from bisulfite conversion.

Bisulfite sequencing is crucial for studying the role of DNA methylation in various biological processes, including development, gene regulation, and disease, particularly cancer. It allows for the identification of specific methylation patterns and their correlation with gene activity or inactivity. While effective, bisulfite sequencing can be technically demanding and requires careful experimental design and data analysis to ensure accurate interpretation of methylation states.