Читать книгу Getting Pregnant For Dummies - Sharon Perkins - Страница 74

An expanding area of research for genetic diseases focuses on how the genetic code is actually read. It turns out that while there is a core code, inherited unchanged from generation to generation, the cell is able to modify how the code is read based upon environmental and developmental conditions. Cells do this by adding molecules to the core code, which is called epigenetics. For example, one theory of how endometriosis forms is that molecules called methyl groups can either be added or removed from the core genetic code, creating new instructions from the genetic code that leads to the formation of endometriosis. Endometriosis is a very complex disease, and this is not the only reason a person develops endometriosis, but the process may add to the risk for developing endometriosis.

A cell requires considerable energy to perform the work it does. The energy is generated by a small structure within the cell called mitochondria. Mitochondria are similar to bacteria and have their own set of chromosomes. When errors occur in these genes, the mitochondria do not perform well. This can lead to devastating diseases. One treatment that is being developed is to take normal mitochondria from an embryonic cell and transfer it into the cell from an affected embryo.

A result of more sophisticated chromosome testing of preimplantation embryos is the discovery that not all embryos are either completely euploid or completely aneuploid. Some embryos have cells that have the correct number of chromosomes while other cells in the same embryo have the wrong number of chromosomes. This is called mosaicism. Currently, research is attempting to determine what percentage of mosaicism is safe for transfer of a mosaic embryo.

A final advancement is the ability to genetically modify the genetic code of an embryo. The technology uses a procedure called CRISPR (technically CRISPR-Cas9). The use of this for clinical medicine is quite a ways off, but the implications are immense. In theory, it may become possible to actually alter the genetic code. This could provide a way to cure inherited diseases or reduce genetic risk factors for a number of chronic diseases. The use of genetics to improve the human condition is called eugenics. The ability to alter the genetic code elevates the field of eugenics to a new level that could challenge both ethics and the legal system. So once again, just as IVF challenged the social environment of reproduction, genetic modification may challenge the social system in very difficult and complex ways.