…[T]hose people who argue that epigenetics implies that you can take active control of your genetic inheritance are full-on wackaloons. If that’s the vanguard of this new revolution in evolutionary theory, it’s doomed. If that’s your belief, you are in [Joe] Mercola territory, and completely wrong.
Paul Zachary “PZ” Myers, professor of biology at the University of Minnesota Morris
Epigenetics Around the Web is a weekly roundup of the latest studies and news in the field of epigenetics presented by GLP sister site the Epigenetics Literacy Project. This week features a video by scientists from the Garvan Institute of Medical Research on how epigenetic changes lead to cancer and scientists devise a way to edit the epigenome.
How epigenetic changes cause cancer
There is a classical view of cancer in which the disease arises via genetic mutations. These mutations cause changes in genes that can make the protein non-functional or over active. But as I pointed out in the December 2 Epigenetics Around the Web post, epigenetic changes can also cause similar changes in a cell. Hypermethylation of a gene important for DNA repair could inhibit the protein’s activity. I linked to a study in which researchers reported that atypical histone modifications seemed to be driving a rare brain cancer independent of gene mutations. But this is not the only example in which cancer can be triggered by epigenetic modifications. This video, created by a student, Armando Hasudungan, in collaboration with Susan Clark and Kate Patterson at the Garvan Institute of Medical Research in Darlinghurst, Sydney, New South Wales, illustrates the ways epigenetic modifications can cause a cell to become cancerous.
Debate: Unified Theory of Evolution
I also linked to a story about a meeting in the United Kingdom at which scientists were debating expanding the theory of evolution to include epigenetics. Proponents, of what is now called the unified theory of evolution believe that the theory of evolution by natural selection fails to tell the whole story of evolution. They say evolution via natural selection moves too slowly to explain some of the adaptations observed in the lab and nature. They believe that the environment can trigger epigenetic changes, which are then passed on to several subsequent generations. This is called transgenerational inheritance.
Arguing on behalf of the unified theory on the science site Aeon is Michael Skinner, a professor of biological science at Washington State University:
Environmentally induced epigenetic transgenerational inheritance has now been observed in plants, insects, fish, birds, rodents, pigs and humans. It is, therefore, a highly conserved phenomenon. The epigenetic transgenerational inheritance of phenotypic trait variation and disease has been shown to occur across a span of at least 10 generations in most organisms, with the most extensive studies done in plants for hundreds of generations.
Arguing against on Science Blogs is Paul Zachary “PZ” Myers, a professor of biology at the University of Minnesota-Morris:
[H]ere we have a group of people declaring that we need to greatly modify the neo-Darwinian Synthesis but they constantly demonstrate that they don’t understand it. You can’t propose changes to an idea if you haven’t done your homework and shown some detailed knowledge of what you think needs revision. They haven’t done their background research.
STAT reporter Sharon Begley set out to examine this claim: Delivery by caesarean section alters a baby’s microbiome in a way that increases the risk of becoming obese and developing asthma or other allergies. What the research has now consistently shown is that a baby’s microbiome is established during gestation. This is a change from previous thinking when it was thought that this happened during birth. This is important because many of the factors that drive women to have to have c-sections are similar to those that alter microbiome composition–such as obesity. So even without the C-section, the baby’s microbiome may already have been altered. The thing to remember is that C-sections save lives—often both the mom and baby.
On November 15, Chinese scientists became the first to use the revolutionary gene editing technique known as CRISPR on a human as part of a treatment for advanced lung cancer. Many experts see numerous applications of gene editing, including curing genetic diseases and tweaking the genes of new born babies–so-called designer babies. However, researchers Peking University, Beijing have a different idea–they don’t want to edit the genome; instead, they focus on the the epigenome. The CRISPR gene editing technique usually consists of two parts: the guide RNA that finds the specific target region of DNA; and an enzyme that cuts the DNA (frequently a protein called Cas9, hence the term CRIPSR/Cas9). In this study, published in Cell, scientists explained that they inactivated the Cas9 protein, and attached a methylating enzyme or a demethylating enzyme. The modified CRISPR system was able to alter gene regulation inside a mouse. This technique could be a valuable tool in research to study the function of specific genes or in medicine, as I described above in cases where a disease (such as cancer) is being driven by abnormal epigenetic modifications.
For more epigenetics news—as well as news about the microbiome and endocrine disruptors—check out the Epigenetics Literacy Project, a sister-site to the GLP.
Nicholas Staropoli is the director of the Epigenetics Literacy Project. He has an M.A. in biology from DePaul University and a B.S. in biomedical sciences from Marist College. Follow him on Twitter @NickfrmBoston.