Isn’t it funny how accents are lost (or gained) over time?
No I have not picked up an American accent, although when I hear myself speak I sound quite bland!
But what I am getting at is that long-lasting effects can be acquired simply due to being immersed in a foreign country: accents are gained without thought, or gained to improve communication (and in the case of the Australian, GET that drink of waterrrrrr). Depending on the individual’s age, accents can be quickly developed: young children develop accents quicker than their grandparents, for example.
OK, so what has this got to do with science and what I am doing over here in San Francisco? Well using the accent analogy, it might be easier to explain how cells can change their gene expression program depending on physical changes to their environment. One theory is that these changes can evoke methylation of genes, and hence provide phenotypic diversity beyond changes to nucleotide sequence. This is because gene methylation is an epigenetic change – epi – above the genes. Typically, methylation at C-G islands, which on the most part, leads to silencing of gene expression.
This process of methylation in response to physical pressure is thought to explain how the cells in your body, which all contain the same set of blueprints (i.e. the genetic material) change into chondrocytes in stiff environments to make cartilage, or change into muscle, or fat cells depending on the physical environment combined with organ-specific factor expression. It also explains the colour variation in calico cats.
Even more cool, DNA methylation has been linked to the formation of memory.
But I digress. Oh yeah, what I am doing here in San Francisco, is to examine gene methylation patterns in cells from the breast, from the ducts that make the milk (epithelial cells) when they are plated on soft and stiff matrices. This is all to understand how mammographic density, which creates a stiffer microenvironment within the breast, contributes to breast cancer. Are the “good” genes that keep cell division in check turned off by methylation? Do methylation patterns change over time in culture? Do cells “remember” the stiffness when plated on a soft surface?
So many questions that I want to find answers for.