We’ve talked a lot about epigenetic inheritance – well, now a new study help further illuminate how the whole epigenetic thing works. Researchers have discovered that a protein called Tet1 is partly responsible for giving primordial germ cells a clean epigenetic slate before developing in sperm and egg cells.
Normally, each of our somatic cells carries two copies of every gene one from each parent. For certain genes, it is important that one of these alleles is imprinted – that is, marked with methyl groups – in order to keep it silent and to prevent conflicts from arising between the two copies. This is done by first erasing and then re-establishing primordial germ cells’ imprinting patterns in an allele-specific manner, before they mature into sperm or egg cells.
In mouse models lacking the Tet1 gene, the researchers found that primordial germ cells were unable to erase their imprints, leading to embryonic lethality and reductions in the size of live-born offspring. Such findings suggest that Tet1 mutations may be a contributor to certain human birth defects.