We Can Now End Malaria With Mass Effect Technology (But Maybe We Shouldn’t)

It’s always neat to see technologies from Science Fiction become reality. Star Trek is famous for featuring technology like communicators (cell phones), replicators (3D Printers), and warp drives (still highly hypothetical, unfortunately). But Star Trek doesn’t have a corner on the market for futuristic technology predictions. Another great sci-fi universe might have a way to end malaria.

Mass Effect is a great series of games set in a future where humans, along with several other species in the galaxy, have discovered ancient alien technology that allows anyone to quickly travel around the galaxy. Humans are late to the technology party, so there is a long galactic history that doesn’t involve us. The games are full of great characters to meet and worlds to explore. It’s also full of some pretty interesting ethical decisions that the player must make and live with the consequences. In an interestingly realistic way, there often isn’t a “right” or “perfect” answer to a given problem. You just have to balance your priorities against the costs.

One of the ethical dilemmas in the galaxy relate to a species called the Krogan. These are a heavy-set, warmongering race that once threatened to take over the galaxy. However, a different species of scientifically inclined aliens had a solution to the perennially troublesome Krogan: keep them from reproducing. To keep the Krogan threat low, the entire species were infected with a genetic disease that prevents most of their children from surviving to birth. The problem is so bad that the Krogan are constantly in serious danger of becoming extinct. Was using the genetic disease the right choice? It might be more defensible than instant genocide, but it’s still a pretty awful thing.

Krogan and strong and prone to violence. If their population gets high enough, war is pretty much inevitable.

Mass Effect never reveals the exact nature of the Krogan genetic disease, but I would guess it would be similar to something that’s now being developed in real life: a Gene Drive. A Gene Drive is a genetic tool that uses some of what we understand about how animals evolve to force a genetic change in a group of animals. It’s a Gene that Drives evolution. These are special genes that have unusual advantages over other genes to let them spread super easily.

Consider how normal inheritance works: both of your parents (probably) have two sex chromosomes; Mom with two X chromosomes and Dad with one X and one Y. Each gave you a copy of one of their chromosomes. Mom gave a copy of one of her two X’s, and Dad gave either an X or a Y. It’s a toss-up which of the two chromosomes you get from each parent, so you had a 50% chance of inheriting any one of your parents’ chromosomes. Genes are sections of DNA on chromosomes, so if only one of Mom’s X chromosomes has an allele (alleles are different versions of the same gene) that is broken, you have a 50% chance of getting that broken allele too. Because this is how the probabilities work,  as long as we ignore all the ways a population can evolve, each allele in a population has the exact same chance to be inherited in the next generation.

That means each allele will forever stay equally as common as long as no other mechanism of evolution is active, no matter how much a population changes in size. If a baldness gene is 1% common when the population is 100, it would be about 1% common if the population grows to 10,000. This is a simplified mathematical description of how it works in reality, but it’s useful for understanding what’s special about Gene Drives. In normal genes, different alleles have about the same chance of being inherited as long as they aren’t beneficial or harmful.

Spreading diagram
A Gene Drive spreading in a population of mosquitos. Only one of the parent mosquitos (blue) has the Gene Drive, but all of the offspring have it. (Adapted from Figure 1 in Esvelt et al. 2014)

Gene Drives cheat the system. They find a way to make it almost certain that they will be inherited instead of only having a 50% chance. There are many types of Gene Drive, but a useful one scientists have designed works as shown in the above picture. In section B, one parent gives a section of DNA containing the Gene Drive, and the other parent gives a section without the Gene Drive, and a new mosquito is conceived. But the Gene Drive checks to see if the other strand of DNA also has a copy of the Drive, and if not, it splices a copy of the Drive into the other strand. The baby mosquito now has 2 copies of the Gene Drive! That means that all of the baby mosquito’s future offspring are sure to inherit the Drive as well.

In fact, as seen in section A, every mosquito descended from the original parent with the Gene Drive ends up also having the Drive. The species is driven to evolve exactly the way the Gene Drive designers wanted. That’s a pretty cool trick in itself, but we can do something useful with it. If we make part of the drive also have a second effect, like being lethal to females, then something dangerous can happen. If descendants carrying the Gene Drive are only producing males, over time that will drastically drive down the number of females there are in the whole population! It is possible for there to eventually be no new females born, forcing the species to go extinct! It’s an impressive genetic technology.

A mosquito of the Anopheles genus. There are over 100 Anopheles species that can carry malaria and spread it to humans.

Fortunately we don’t have a big Krogan problem on Earth, but we do have a big mosquito problem. In 2010 around $1.71 billion US was spent trying to control malaria spreading to humans from mosquitos. [2] Despite that big spending, there were 219 million cases of malaria that year, and 660,000 deaths. [2] Malaria is just one of the deadly diseases that can be spread by these mosquitoes. The WHO estimates that it would take $5.1 billion US per year to get malaria under control with traditional means like insecticides, nets, and better access of health care. [2] We’re a long way off that amount of cash being invested, and designing a building a Gene Drive to simply get rid of all of the problem mosquitos would likely cost less than $1 billion. As a bonus, it would only require a few doses instead of being a yearly cost indefinitely.

So why not? Krogans are intelligent like humans, so doing it to them seems cruel. Mosquitoes are not so intelligent. I certainly don’t think that emotional trauma due to a mosquito’s inability to reproduce normally is a serious concern here.

Scientists do have some legitimate concerns, though. What would happen if there were suddenly no more mosquitos in an ecosystem? What if the gene spread to mosquitos on continents where malaria isn’t a problem and disturbed ecosystems worldwide? What if the gene managed to spread to other, non-dangerous mosquito species? From a Christian perspective, is causing the extinction of one of God’s creatures ever a good thing? There are not perfect answers to these challenges. There are always risks, and to get a benefit we have to pay a price. Once a species is extinct you just have to live with your decision that you can’t take back. Proper consideration before using this technology is needed, but while we’re busy deliberating there are hundreds of thousands of people dying every year from a terrible disease.

Gene Drives for combating mosquitos aren’t here yet, but they are currently being developed and will be available soon.  This is the sort of real modern bioethics problem that it’s important for Christians and churches to seriously ponder. These are the sort of critical decisions that biotechnology is bringing us, and we must work hard to make the best decisions we can.

Literature Cited

[1] Esvelt KM, Smidler AL, Catteruccia F, Church GM. 2014. Emerging technology:
concerning RNA-guided gene drives for the alteration of wild
populations. eLife 2014 (3): e03401

[2] [WHO] World Health Organization. 2012. World Malaria Report 2012. Geneva
(CH): World Health Organization; accessed 2016 Aug 8]. http://www.who.int






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