A major mouse study found that some inherited traits are passed down through epigenetic changes that break the classic rules of genetics. Researchers discovered hundreds of cases where these chemical DNA marks behaved unexpectedly, including some that seemed to emerge out of nowhere. They also identified the first known naturally occurring paramutation in a mammal, hinting that environmental influences may play a larger role in inheritance than scientists realized.
Genetic information in the DNA and modifications, such as DNA methylation, define the epigenetic landscape and phenotype and show both Mendelian and non-Mendelian heredity. In addition to genes themselves, parents can pass along epigenetic changes. These are chemical modifications that affect how genes function without altering the underlying DNA code.
Now, a new federally funded study in mice suggests that some of these inherited epigenetic marks do not follow Mendel’s classic laws. Researchers found that about 7% of the epigenetic inheritance patterns they examined behaved in unexpected ways. The study also uncovered rare forms of inheritance previously seen in plants and flies but not in mammals. “Non-Mendelian patterns of inheriting epigenetics could be a faster way to acquire diverse or new traits than alterations in the genomic sequence itself, especially in response to environmental pressures,” says Andrew Feinberg, M.D., Bloomberg Distinguished Professor in the Johns Hopkins University School of Medicine, Whiting School of Engineering and Bloomberg School of Public Health, and co-leader of the research with colleagues at Texas A&M University.
Source: https://www.nature.com
