For long scientists have known that cells differentiate to become organs, some cells become heart while others become kidneys but whether a cell can return to its former undifferentiated form was a poorly understood concept uptil now. Hehuang Xie and his team at the Virginia Bioinformatics Institute at Virginia Tech have uncovered that the answer to this question may be related to a process called ‘DNA methylation‘ and this answer can help find cure to cancer and other inherited diseases.
Epigenetic (study of changes in gene expressions) plays a great role in how traits are expressed and how the history of the expression of traits is passed down. Epigenetic changes are not simple DNA mutations. On the contrary, they alter the ‘Chromatin’. Chromatin is the blocks of protein and DNA that build chromosomes and direct gene expression. These changes in chromatin are passed onto future generations and can provide clues to inheritance of many diseases including cancer.
In the process of DNA methylation, a methyl group is added to DNA, this is one way in which the expression of gene might be altered. DNA methylation patterns are heritable, by tracing these patterns scientists could find out how cancers begin since methylation helps cells differentiate into specific tissues but tracing these patterns had been impossible uptil now.
Xie and his colleagues found a way to study methylation patterns making it the first time that methylation patterns have been studied across the entire genome.
To study the patterns, they used a technique called hairpin bisulfite sequencing. This method was previously used to look at specific sequences in a genome to find out whether the methylation patterns have been passed on to the daughter cells from the mother cell. Xie used this method to look at the entire genomes using next generation sequencing techniques to monitor DNA methylation inheritance.
Xie and his team integrated hairpin bisulphite data with various ‘-omics’ data to scrutinize the inheritance of DNA methylation patterns that are difficult to track. They discovered that accurate methylation inheritance is highly dependent on binding of specific trans-factors to local sequences.
This observation will lead scientists to a greater understanding of cancers and environmental and other undiscovered factors contributing to them. Besides, the genome-wide hairpin bisulfite sequencing technique Xie and his team developed provides several advantage over traditional strategies for DNA methylation studies and does not add to the cost.