Thanks to gene therapy, this monkey can distinguish shades of red and green.

If nature gave you some bum genes, you’ve got a chance of fixing them. Genetic treatments have allowed researchers to cure color blindness in two squirrel monkeys. As published this month in Nature, gene therapy allowed two males to begin producing the L-opsin protein that allowed them to finally see reds and greens. Besides viewing the world in color, what’s the benefit of genetic treatments? Endless supplies of grape juice. Check out the short video below of one of the monkeys getting a reward for identifying red spots during a test.

When any form of blindness has a genetic cause, the promise of restored sight through genetic treatment lingers. We saw the first such case of gene therapy restoring sight when it was used to cure Leber’s congenital amaurosis (LCA) in human children. Those tests were revolutionary, but monkey technicolor vision is remarkable as well. Most scientists believed that adult brains do not have the same rewiring capabilities and plasticity as young brains. Yet the two adult monkeys, Sam and Dalton, started receiving and comprehending new signals once the L-opsin gene was introduced into their retinas.

All male squirrel monkeys are color blind, making them ideal for the test. Furthermore, the mechanism for their color blindness (the lack of L-opsin protein) is similar to many cases of human color blindness. The same method of gene therapy that was used in the LCA tests, was adapted to help monkeys produce opsin. First, scientists knew which gene codes for L-opsin production. A virus was created to carry that gene. The virus was then injected into the monkey’s retina. Like any self-respecting virus, it infected cells and in the process passed on the new gene. These upgraded cells in the retina now had the gene to produce L-opsin and boom…monkeys see in full color.

While the research was only recently published, it took place over several years. After gene therapy, it took five months of rewards-based testing (like that in the video) to discover that the squirrel monkeys could detect shades of red. It is unclear if that time was due to the slow development or adaptation of neural pathways, or the cognitive progression of the monkeys. In fact, the mechanism for how the monkeys’ brains were changed to receive the new input is not well understood at all. The change is likely very stable – the monkeys have retained their new color perception for the more than two years that have passed since testing began.

The fact remains that we are years from seeing color blind gene therapy being offered to humans. It is obviously still in the animal testing phase. The LCA treatment was for safety testing, not efficacy testing, so there are years of study ahead in that field as well. Still, genetic treatments are advancing and could one day be used to cure advanced macular degeneration (AMD), and other common forms of blindness.

And gene therapy isn’t just limited to the eye. Cures for almost any genetic condition could be done in a similar manner to the blindness treatments. In theory, all it takes to fix an illness is finding the responsible gene and replacing it. We could see these treatments rise in availability in the next ten to twenty years.

Gene therapy could also allow us to update our genes so that we could view colors outside our natural range, or develop low-light vision as good as other animals. Enhancements for oxygen absorption could make super athletes out of everyone.  Such possibilities are likely decades away, but they’re not out of the question.

I have two mothers and one father! WTF?

Scientists at the Oregon Health and Science University (OHSU) were able to produce the first primates with three biological parents. Four macaque monkeys were born through an in vitro fertilization process in which the DNA of two females and one male were combined. Of the two mothers, one provided all the chromosomal DNA while the other only provided mitochondrial DNA. This technique may eventually be developed into a treatment in humans so that women with defects in their mitochondria can have healthy offspring. The successful test also raises concerns about genetically engineered babies because the new monkeys will pass on the genetic alterations to their offspring.

The mitochondria organelle often gets called the power house of the cell because of its role in creating energy releasing molecules. However, it could also be called the ticking time bomb of the cell because as many as 1 in 4000 people develop illnesses due to defects in their mitochondrial DNA. Sometimes these defects can be passed on from a mother who has no outward signs of the condition. Those people with this type of genetic problem have risks for certain kinds of epilepsy, cancer, diabetes, heart disease, liver disease, deafness and blindness. The work at OHSU demonstrates that a carrier could pass on the 99% of her DNA that is healthy (chromosomal) and use a donor to fill in the missing 1%.

Shoukhrat Mitalipov from the Oregon National Primate Research Center lead the study. The four healthy macaque monkeys (named Mito, Tracker, Spindle, and Spindly) are a good first step in his plans to eventually bring the technique to humans. However, Mitalipov is quick to point out that a technique is not a treatment, and it will likely be several more years before human clinical trials could be considered. Additionally, he would need to see how the new monkeys produce offspring to see if there are any problems with the passing of genetically altered DNA to offspring.

Twin monkeys, Mito and Tracker, are the result of a mitochondrial DNA swap between mothers.

The passing on of genetic alterations, called germline engineering, has raised a lot of interest for medical ethicists. Mitalipov’s work is a remarkably specialized case of germline engineering: only mitochondrial DNA was swapped out, and its goal is purely to avoid known defects. In the grander scheme of things though, germline engineering could lead to designer babies if applied to chromosomal DNA. Currently, the hoops it would take to produce an engineered human baby are many: USDA approval, using only private or state funds, and bypassing laws which forbid clinical trials using genetically modified embryos.

Similar laws are in place in the UK where Newcastle University is pursuing results closely related to the work done at OHSU. Scientists there have a similar technique (though it is reputedly less efficient and has DNA swaps occurring after insemination). And some British scientists are working to get exemptions from their Human Fertilization and Embryology Act (HFEA). That law prohibits implanted altered embryos into a womb.

The fact that four baby monkeys are raising such concern shows the importance of germline engineering. The OHSU work, which focuses on one day helping to cure a certain kind of DNA defects may also reveal how designer babies eventually find their way to market. Parents want the best for their children, genetically as well as environmentally. If their exists a way for them to avoid giving their child a few bad genes, they are likely to take it. As we’ve said before, parents are already selecting embryos for that very reason. It’s only a matter of time before swapping DNA between mothers stops being just monkey-business.

Could you say no to a face this cute? Nope, and that's why we'll have designer babies.

[photo credits: Nature]