What is Germline Gene Therapy?

To be brief, germline gene therapy involves altering the genetic makeup of either an egg or sperm cell before fertilization, or altering the genetic makeup of the blastomere when it is in a very early stage of division. The goal of germline gene therapy is to effect changes in the genetic code of an organism that will be passed on to future generations. (6)

One method of germline gene therapy involves altering the genetic makeup of an egg or sperm before fertilization occurrs. By doing so, one ensures that the mutations are passed on to future generations. As one might recall from our Introduction to Sexual Reproduction, it is the combined gametes, or zygote, that will divide to give rise to all the other cells of the body, including those cells that will become the gametes (sperm or egg) of the next generation. If the gamete of one of the parents is genetically altered, all of the cells of the child, including the germ cells, will posess the same genetic alteration.

Another method of germline gene therapy involves altering the genetic makeup of some of the cells of the blastomere when it is at a very early stage of development. The altered cells are allowed to continue to divide, and then the animal develops, some of its cells will possess the genetic alteration and some will not. If the cells that possess the genetic alteration develop into the germ cells of the organism, then the alteration will be passed on to future generations as discussed above. If not, future generations will not posess the genetic alteration.

How is Germline Gene Therapy Done?

Germline gene therapy is only at the beginning stages of its development, and thus the processes for its accomplishment are underdeveloped and not much is known yet. Germline gene therapy isn't even being done in humans yet! However, scientists are working on one specific process that they believe will eventually be able to use in humans. The most important thing to remember is that germline gene therapy involves the altering of the genetic makeup of the egg or sperm, and therefore the alterations will be passed on to future generations. For a more detailed look at the processes of germline gene therapy, visit one of the following links: Germline therapy in the egg or sperm, Germline therapy with the blastomere, and the Lab Processes of Germline therapy.

How is Germline Gene Therapy being Used Today?

Ah, the focus of our website! As we have mentioned before, germline gene therapy is not yet being used in humans due to a combination of lack of development of techniques and a heated debate over the ethical issues of the process. However, a great deal of interesting research is being done on other mammals. Click here to learn about Current Uses of Germline Gene Therapy. Click here to get a look into the Future of Germline Gene Therapy!