The Biology of Belief - Bruce H. Lipton [29]
In this epigenetic analogy, the test pattern on the screen represents the protein backbone pattern encoded by a gene. While the TV’s controls can change the appearance of the pattern (B and C), they do not change the original pattern of the broadcast (i.e., the gene). Epigenetic control modifies the read-out of a gene without changing the DNA code.
Parental Life Experiences Shape Their Children’s Genetic Character
We now know that the environmentally influenced fine-tuning described above can be passed from generation to generation. A landmark Duke University study published in the August 1, 2003 issue of Molecular and Cellular Biology found that an enriched environment can even override genetic mutations in mice. (Waterland and Jirtle 2003) In the study, scientists looked at the effect of dietary supplements on pregnant mice with the abnormal “agouti” gene. Agouti mice have yellow coats and are extremely obese, which predisposes them to cardiovascular disease, diabetes, and cancer.
Agouti Sisters. One year old female genetically identical agouti mice. Maternal methyl donor supplementation shifts coat color of the offspring from yellow to brown and reduces the incidence of obesity, diabetes, and cancer. (Photo courtesy of Jirtle and Waterland©)
In the experiment, one group of yellow, obese, agouti mothers received methyl-group-rich supplements available in health food stores: folic acid, vitamin B12, betaine, and choline. Methyl-rich supplements were chosen because a number of studies have shown that the methyl chemical group is involved with epigenetic modifications. When methyl groups attach to a gene’s DNA, it changes the binding characteristics of regulatory chromosomal proteins. If the proteins bind too tightly to the gene, the protein sleeve cannot be removed and the gene cannot be read. Methylating DNA can silence or modify gene activity.
This time the headlines “Diet Trumps Genes” were accurate. The mothers who got the methyl-group-rich supplements produced standard, lean, brown mice, even though their offspring had the same agouti gene as their mothers. The agouti mothers who didn’t get the supplements produced yellow pups, which ate much more than the brown pups. The yellow pups wound up weighing almost twice as much as their lean, “pseudo-agouti” counterparts.
The University’s photo on the previous page is striking. Though the two mice are genetically identical, they are radically different in appearance: one mouse is lean and brown and the other mouse is obese and yellow. What you can’t see in the picture is that the obese mouse is diabetic while its genetically identical counterpart is healthy.
Other studies have found epigenetic mechanisms to be a factor in a variety of diseases, including cancer, cardiovascular disease, and diabetes. In fact, only 5 percent of cancer and cardiovascular patients can attribute their disease to heredity. (Willett 2002) While the media made a big hoopla over the discovery of the BRCA1 and BRCA2 breast cancer genes, they failed to emphasize that ninety-five percent of breast cancers are not due to inherited genes. The malignancies in a significant number of cancer patients are derived from environmentally induced epigenetic alterations and not defective genes. (Kling 2003; Jones 2001; Seppa 2000; Baylin 1997)
The epigenetic evidence has become so compelling that some brave scientists are even invoking the “L” word for Jean Baptiste de Lamarck, the much-scorned evolutionist, who believed that traits acquired as a result of environmental influence could be passed on. Philosopher Eva Jablonka and biologist Marion Lamb wrote in their 1995 book Epigenetic Inheritance and Evolution—The Lamarckian Dimension: “In recent years, molecular biology has shown that the genome is far more fluid and responsive to the environment than previously supposed. It has also shown that information can be transmitted to descendants in ways other than through the base sequence of DNA.” (Jablonka and Lamb 1995)
We’re back to where we started in this chapter,