Human Gene Editing Supported by Science Panel

Human Gene Editing Receives Science Panel's Support

Just like any field of study, genetics entails some pretty controversial topics. One of the most debatable advances in genetics research is the idea of physically modifying human embryos in order to create genetic traits that can be passed down to future offspring. For many years it has been difficult to define the ethical background of this technique. It is widely feared that this technology could and would be used to enhance intelligence or to create physical specimens to eventually serve as soldiers. This article reports that an advisory group of scientists has endorsed gene editing in order to alter/prevent babies from acquiring genes that cause serious disease when there is no other alternative intervention. Human germ line engineering, as this technique is called, will allow parents to have biological children without passing on the genes for Huntington’s or Tay-Sachs disease, for example.

            I found this article to be really relevant and interesting. To be able to alter genetic traits in human embryos is an incredible advancement that should be used, but only for the right reasons. As incredible as technology is becoming, who knows what catastrophes could result from putting this type of power into the wrong hands. This topic should not be taken lightly and should abide by a strict set of ethical laws. Personally, I think any advancement is a good advancement. A few years ago, this would have never even been thought to be possible. Now, according to this article, “the National Academy of Sciences and the National Academy of Medicine has lent its support for this once-unthinkable proposition”.

A related article says that China will develop the first genetically enhanced super-humans using the same germ line engineering technology. 

Controversial Gene-Editing Approach Gains Ground

The field of genetics advances further as researchers are now brainstorming and taking steps to learn how we can replace or "fix" damaged DNA that leads to inherited diseases. As we know, mutations in DNA can lead to severe mental, physical, biological disorders, or even sometimes death. Scientists are now doing what's being called gene-editing, and are "snipping out" damaged mitochondrial DNA, removing the mutations, and replacing it.

Using this method, so far researchers have removed mutations in mitochondrial DNA mostly in mice and human cells. The science behind this technique is as follows: enzyme called TALENs (transcription activator-like effector nucleases), work in pairs to search for and cut away damaged mitochondrial DNA in maternal eggs, all while leaving other genetic material untouched. It sounds promising, and so far TALENs have also been tested in modifying genes in frogs, rats, pigs, and human stem cells. One major problem standing in the way is the whole idea of "genome editing" in human embryos because we do not know the long term effects on germ line cells. (Germ line modifications are, "changes that are made to the DNA found in the nucleus of a sperm or egg before fertilization...").

This technique appears to have worked when tested on two generations of mice, and the offspring have had low levels of inherited mitochondrial mutations, meaning future generations may have a very small chance of inheriting a genetic disease. A team of scientists are now beginning to test this in human embryos. They are hoping for this method to only change the unwanted DNA and not affect healthy material. If so, then it opens a lot of doors to "genome editing" science. For some, there are still worries about the ethics of this practice.

I think that this type of science could help significantly decrease genetic disorders and be beneficial to people who have a history of genetic disorders in their families who want children. Personally, I don't think this should be an ethical issue because it's not like "designer babies" where people are changing the (for example) eye color of their kids just because they want it. This is for an actual health reason. Even though the future effects are not yet known, I think any life is better than no life.

Original Article 

Related 

Maternal Age Effect in Mitochondrial Disorders

At the age of 35 years-old, women are put into the high-risk category for their pregnancies, outlining an increased risk for both the mother's and the baby's health. It has been commonly accepted that with age, pregnant mothers are more likely to have children with chromosomal defects and other inherited issues due to increased mutations in maternal egg cells; however, the extent to which these mutations may affect the baby has been unclear. 

A team of Penn State scientists recently discovered a "maternal age effect" which could be indicative of the number of mitochondrial DNA (mtDNA) mutations in maternal egg cells, and the likelihood of transmission of these mutations to babies. Mitochondrial DNA is solely inherited maternally; therefore, any mtDNA mutations the mother accumulates has the potential to affect her baby. These mutations can cause a vast array of devastating diseases and "contribute to others such as diabetes, cancer, Parkinson's disease, and Alzheimer's disease," making the "maternal age affect" of great interest to the field of genetic counseling. 

The goal of the team's research was to determine whether maternal age was "important in the accumulation of mtDNA mutations both in the mother and the child as a result of transmission." The researchers took blood and cheek cell samples in women 25 to 59 years-old. Using DNA sequencing, the researchers found more mutations in the older mothers. Greater rates of mutations were also found in children of the older mothers, leading the researchers to hypothesize that a similar mutation process occurs "in the cells of the mothers' bodies and in their germ lines." 

The above discovery also guided the researchers to another discovery regarding egg-cell development. While it has been accepted that "developing egg cells go through a 'bottleneck' period that decreases the number of mtDNA molecules," the magnitude of the bottleneck period had not been determined. A large bottleneck would imply that the genetic makeup of the maternal mitochondria would be inherited by the children, and a small bottleneck could result in drastic differences in the genetic makeup of mitochondria between the mother and her child. Through the study, the researchers determined the bottleneck is tiny. This discovery has major implications on genetic counseling, including the ability to predict a percentage range of disease-carrying molecules that will be inherited by the child.

I think the research developed by the Penn State team is extremely important to the field of genetic counseling and family planning. In our current culture, women are starting to have children later in life in order to accomplish career goals and to properly prepare for becoming a mother. However, the decision to procrastinate having children is accompanied by an increased risk for passing down life-altering disorders. While having a baby with Down syndrome is the typical concern for older mothers, genetic counselors can now provide mothers with the probability of having a child with another set of genetic disorders that may be correlated with the mother's age. I think this research could be a gateway for discovering how to reduce the risk of having a child with a chromosomal or mitochondrial disorder in older mothers.

Article: http://science.psu.edu/news-and-events/2014-news/Makova10-2014

Related article: http://www.pnas.org/content/77/11/6715.full.pdf+html