This may help to answer many questions.  How can we have so many different types of cells and they all carry the same genetic information?  How is it possible for one identical twin to develop cancer while the other does not?  Can we use this control of the gene expression to help cells that may have lost their way?

It is amazing to think that just about all of the cells of the human body has the same DNA.  The full genetic profile with all of the instructions on how to make a human is in almost every cell.  When most students come through the DNA Learning Center, many of them think that there is different DNA inside of these cells.  That red blood cells have different DNA than bone cells and nerve cells.  One way this is done is through the interaction of small methyl groups (-CH₃) that get added to the DNA molecule, which can help to silence a gene that is not needed in some type of cell or at some point of development.  This is a epigenetic “tag” because there is no change to the sequence of DNA, it is just whether or not there is access to the DNA.  The methyl groups that get added make the cell unable to activate that gene.

This addition of methyl groups, called methylation, also can change throughout the course of our life.  So as we get older the interaction of these groups with our DNA can change.  So even with identical twins, who are born with the same DNA, their epigenetic “tags” can vary and occur independent of one another.  And even more, certain lifestyle choices and experiences throughout the life of a person can change the epigenetic profile of an individual.  And then this gets passed on to our children.  So even what a mother eats while pregnant can affect the tags that get passed to their child.  This ultimately will affect the expression of genes in the child.

And now we are using this information to help treat disease, such as cancer.  So if a gene is turned on that shouldn’t be, could we add methyl groups to that section of the DNA to turn it off?  This has started being used as a new therapy for the treatment for certain cancers.

Progeria is a very rare, genetic disorder that afflicts roughly one in 5 million people. It is caused by a mutation in the LaminA gene on chromosome 1. The most striking symptom of Progeria-afflicted children is that they age rapidly. They frequently succumb to coronary artery disease before they reach 20 years of age.

Directed by R Balakrishnan the Indian movie company AB Corp Ltd. has released the movie “Paa”. The picture’s protagonist is a 13-year old boy afflicted with progeria – and is being played by an actor who is actually in his 60s. AB Corp Ltd. proclaims that Paa is not a movie about the disease Progeria, but about “how special children can fill your life with special brightness.”

Read more: about Progeria at the Progeria Research Foundation; about living with serious genetic disorders at the DNALC’s Your Genes, Your Health site.