Of lizards, men, cancer and evolution
Rapidly evolving lizards introduced to the tiny island of Pod Mrcaru off the coast of Croatia surprised biologists with how rapidly their physical structure changed. Just a few decades produced a new, ridged gut, larger head and harder bite. And all this happened with no significant change to the lizard’s genetic code.
A process called ‘DNA methylation’ is capable of turning certain genes on or off without altering the genetic code itself. Studies have indicated that organisms have the theoretical potential to inherit these aquired changes, allowing for a kind of neo-lamarkianism. How often that happens and under what circumstances is still a matter of debate.
Skin cells, nerve cells gut cells and cancer cells all have different genes turned off and on, which is part of what makes them what they are. This list of which genes are on and which are silenced for a type of cell is called its methylome. On Oct. 14, 2009, the first complete methylome for a particular type of human cell was published in the journal Nature.
This paper documents the first complete mapping of the methylome, a subset of the entire epigenome, of 2 types of human cells – an embryonic stem cell and a human fibroblast line. This will help us better understand how a diseased cell differs from a normal cell, which will enhance our understanding of the pathways of various diseases.”source“
This marks a milestone in our ability to fight disease as well as to understand the processes by which species evolve; a process that looks to be far less random than many had once assumed.