SCOOP: Largest Cryobank in the U.S. to Offer Ancestry Testing
Sharon Kochlany and Vanessa Colimorio's four-year-old twin girls had a classic school assignment recently: make a family tree. They drew themselves and their one-year-old brother branching off from their moms, with aunts, uncles, and grandparents forking off to the sides.
The recently-gained sovereignty of queer families stands to be lost if a consumer DNA test brings a stranger's identity out of the woodwork.
What you don't see in the invisible space between Kochlany and Colimorio, however, is the sperm donor they used to conceive all three children.
To look at a family tree like this is to see in its purest form that kinship can supersede biology—the boundaries of where this family starts and stops are clear to everyone in it, in spite of a third party's genetic involvement. This kind of self-definition has always been synonymous with LGBTQ families, especially those that rely on donor gametes (sperm or eggs) to exist.
But the world around them has changed quite suddenly: The recent consumer DNA testing boom has made it more complicated than ever for families built through reproductive technology—openly, not secretively—to maintain the strong sense of autonomy and privacy that can be crucial for their emotional security. Prospective parents and cryobanks are now mulling how best to bring a new generation of donor-conceived people into this world in a way that leaves open the choice to know more about their ancestry without obliterating an equally important choice: the right not to know about biological relatives.
For queer parents who have long fought for social acceptance, having a biological relationship to their children has been revolutionary, and using an unknown donor as a means to this end especially so. Getting help from a friend often comes with the expectation that the friend will also have social involvement in the family, which some people are comfortable with, but being able to access sperm from an unknown donor—which queer parents have only been able to openly do since the early 1980s—grants them the reproductive autonomy to create families seemingly on their own. That recently-gained sovereignty stands to be lost if a consumer DNA test brings a stranger's identity out of the woodwork.
At the same time, it's natural for donor-conceived people to want to know more about where they come from ethnically, even if they don't want to know the identity of their donor. As a donor-conceived person myself, I know my donor's self-reported ethnicity, but have often wondered how accurate it is.
Opening the Pandora's box of a consumer DNA test as a way to find out has always felt profoundly unappealing to me, however. Many people have accidentally learned they're donor-conceived by unwittingly using these tools, but I already know that about myself going in, and subsequently know I'll be connected to a large web of people whose existence I'm not interested in learning about. In addition to possibly identifying my anonymous donor, his family could also show up, along with any donor-siblings—other people with whom I share a donor. My single lesbian mom is enough for me, and the trade off to learn more about my ethnic ancestry has never seemed worth it.
In 1992, when I was born, no one was planning for how consumer DNA tests might upend or illuminate one's sense of self. But the donor community has always had to stay nimble with balancing privacy concerns and psychological well-being, so it should come as no surprise that figuring out how to do so in 2020 includes finding a way to offer ancestry insight while circumventing consumer DNA tests.
A New Paradigm
This is the rationale behind unprecedented industry news that LeapsMag can exclusively break: Within the next few weeks, California Cryobank, the largest cryobank in the country, will begin offering genetically-verified ancestry information on the free public part of every donor's anonymous profile in its database, something no other cryobanks yet offer (an exact launch date was not available at the time of publication). Currently, California Cryobank's donor profiles include a short self-reported list that might merely say, "Ancestry: German, Lebanese, Scottish."
The new information will be a report in pie chart form that details exactly what percentages of a donor's DNA come from up to 26 ethnicities—it's analogous to, but on a smaller scale than, the format offered by consumer DNA testing companies, and uses the same base technology that looks for single nucleotide polymorphisms in DNA that are associated with specific ethnicities. But crucially, because the donor takes the DNA test through California Cryobank, not a consumer-facing service, the information is not connected in a network to anyone else's DNA test. It's also taken before any offspring exist so there's no chance of revealing a donor-conceived person's identity this way.
Later, when a donor-conceived person is born, grows up, and wants information about their ethnicity from the donor side, all they need is their donor's anonymous ID number to look it up. The donor-conceived person never takes a genetic test, and therefore also can't accidentally find donor siblings this way. People who want to be connected to donor siblings can use a sibling registry where other people who want to be found share donor ID numbers and look for matches (this is something that's been available for decades, and remains so).
"With genetic testing, you have no control over who reaches out to you, and at what point in your life."
California Cryobank will require all new donors to consent to this extra level of genetic testing, setting a new standard for what information prospective parents and donor-conceived people can expect to have. In the immediate, this information will be most useful for prospective parents looking for donors with specific backgrounds, possibly ones similar to their own.
It's a solution that was actually hiding in plain sight. Two years ago, California Cryobank's partner Sema4, the company handling the genetic carrier testing that's used to screen for heritable diseases, started analyzing ethnic data in its samples. That extra information was being collected because it can help calculate a more accurate assessment of genetic risks that run in certain populations—like Ashkenazi Jews and Tay Sachs disease—than relying on oral family histories. Shortly after a plan to start collecting these extra data, Jamie Shamonki, chief medical officer of California Cryobank, realized the companies would be sitting on a goldmine for a different reason.
"I didn't want to use one of these genetic testing companies like Ancestry to accomplish this," says Shamonki. "The whole thing we're trying to accomplish is also privacy."
Consumer-facing DNA testing companies are not HIPAA compliant (whereas Sema4, which isn't direct-to-consumer, is HIPAA compliant), which means there are no legal privacy protections covering people who add their DNA to these databases. Although some companies, like 23andMe, allow users to opt-out of being connected with genetic relatives, the language can be confusing to navigate, requires a high level of knowledge and self-advocacy on the user's part, and, as an opt-out system, is not set up to protect the user from unwanted information by default; many unwittingly walk right into such information as a result.
Additionally, because consumer-facing DNA testing companies operate outside the legal purview that applies to other health care entities, like hospitals, even a person who does opt-out of being linked to genetic relatives is not protected in perpetuity from being re-identified in the future by a change in company policy. The safest option for people with privacy concerns is to stay out of these databases altogether.
For California Cryobank, the new information about donor heritage won't retroactively be added to older profiles in the system, so donor-conceived people who already exist won't benefit from the ancestry tool, but it'll be the new standard going forward. The company has about 500 available donors right now, many of which have been in their registry for a while; about 100 of those donors, all new, will have this ancestry data on their profiles.
Shamonki says it has taken about two years to get to the point of publicly including ancestry information on a donor's profile because it takes about nine months of medical and psychological screening for a donor to go from walking through the door to being added to their registry. The company wanted to wait to launch until it could offer this information for a significant number of donors. As more new donors come online under the new protocol, the number with ancestry information on their profiles will go up.
For Parents: An Unexpected Complication
While this change will no doubt be welcome progress for LGBTQ families contemplating parenthood, it'll never be possible to put this entire new order back in the box. What are such families who already have donor-conceived children losing in today's world of widespread consumer genetic testing?
Kochlany and Colimorio's twins aren't themselves much older than the moment at-home DNA testing really started to take off. They were born in 2015, and two years later the industry saw its most significant spike. By now, more than 26 million people's DNA is in databases like 23andMe and Ancestry; as a result, it's estimated that within a year, 90 percent of Americans of European descent will be identifiable through these consumer databases, by way of genetic third cousins, even if they didn't want to be found and never took the test themselves. This was the principle behind solving the Golden State Killer cold case.
The waning of privacy through consumer DNA testing fundamentally clashes with the priorities of the cyrobank industry, which has long sought to protect the privacy of donor-conceived people, even as open identification became standard. Since the 1980s, donors have been able to allow their identity to be released to any offspring who is at least 18 and wants the information. Lesbian moms pushed for this option early on so their children—who would obviously know they couldn't possibly be the biological product of both parents—would never feel cut off from the chance to know more about themselves. But importantly, the openness is not a two-way street: the donors can't ever ask for the identities of their offspring. It's the latter that consumer DNA testing really puts at stake.
"23andMe basically created the possibility that there will be donors who will have contact with their donor-conceived children, and that's not something that I think the donor community is comfortable with," says I. Glenn Cohen, director of Harvard Law School's Center for Health Law Policy, Biotechnology & Bioethics. "That's about the donor's autonomy, not the rearing parents' autonomy, or the donor-conceived child's autonomy."
Kochlany and Colimorio have an open identification donor and fully support their children reaching out to California Cryobank to get more information about him if they want to when they're 18, but having a singular name revealed isn't the same thing as having contact, nor is it the same thing as revealing a web of dozens of extended genetic relations. Their concern now is that if their kids participate in genetic testing, a stranger—someone they're careful to refer to as only "the donor" and never "dad"—will reach out to the children to begin some kind of relationship. They know other people who are contemplating giving their children DNA tests, and feel staunchly that it wouldn't be right for their family.
"With genetic testing, you have no control over who reaches out to you, and at what point in your life," Kochlany says. "[People] reaching out and trying to say, 'Hey I know who your dad is' throws a curveball. It's like, 'Wait, I never thought I had a dad.' It might put insecurities in their minds."
"We want them to have the opportunity to choose whether or not they want to reach out," Colimorio adds.
Kochlany says that when their twins are old enough to start asking questions, she and Colimorio plan to frame it like this: "The donor was kind of like a technology that helped us make you a person, and make sure that you exist," she says, role playing a conversation with their kids. "But it's not necessarily that you're looking to this person [for] support or love, or because you're missing a piece."
It's a line in the sand that's present even for couples still far off from conceiving. When Mallory Schwartz, a film and TV producer in Los Angeles, and Lauren Pietra, a marriage and family therapy associate (and Shamonki's step-daughter), talk about getting married someday, it's a package deal with talking about how they'll approach having kids. They feel there are too many variables and choices to make around family planning as a same-sex couple these days to not have those conversations simultaneously. Consumer DNA databases are already on their minds.
"It frustrates me that the DNA databases are just totally unregulated," says Schwartz. "I hope they are by the time we do this. I think everyone deserves a right to privacy when making your family [using a sperm donor]."
"I wouldn't want to create a world where people who are donor-conceived feel like they can't participate in this technology because they're trying to shut out [other] information."
On the prospect of having a donor relation pop up non-consensually for a future child, Pietra says, "I don't like it. It would be really disappointing if the child didn't want [contact], and unfortunately they're on the receiving end."
You can see how important preserving the right to keep this door closed is when you look at what's going on at The Sperm Bank of California. This pioneering cryobank was the first in the world to openly serve LGBTQ people and single women, and also the first to offer the open identification option when it opened in 1982, but not as many people are asking for their donor's identity as expected.
"We're finding a third of young people are coming forward for their donor's identity," says Alice Ruby, executive director. "We thought it would be a higher number." Viewed the other way, two-thirds of the donor-conceived people who could ethically get their donor's identity through The Sperm Bank of California are not asking the cryobank for it.
Ruby says that part of what historically made an open identification program appealing, rather than invasive or nerve-wracking, is how rigidly it's always been formatted around mutual consent, and protects against surprises for all parties. Those [donor-conceived people] who wanted more information were never barred from it, while those who wanted to remain in the dark could. No one group's wish eclipsed the other's. The potential breakdown of a system built around consent, expectations, and respect for privacy is why unregulated consumer DNA testing is most concerning to her as a path for connecting with genetic relatives.
For the last few decades in cryobanks around the world, the largest cohort of people seeking out donor sperm has been lesbian couples, followed by single women. For infertile heterosexual couples, the smallest client demographic, Ruby says donor sperm offers a solution to a medical problem, but in contrast, it historically "provided the ability for [lesbian] couples and single moms to have some reproductive autonomy." Yes, it was still a solution to a biological problem, but it was also a solution to a social one.
The Sperm Bank of California updated its registration forms to include language urging parents, donor-conceived people, and donors not to use consumer DNA tests, and to go through the cryobank if they, understandably, want to learn more about who they're connected to. But truthfully, there's not much else cryobanks can do to protect clients on any side of the donor transaction from surprise contact right now—especially not from relatives of the donor who may not even know someone in their family has donated sperm.
A Tricky Position
Personally, I've known I was donor-conceived from day one. It has never been a source of confusion, angst, or curiosity, and in fact has never loomed particularly large for me in any way. I see it merely as a type of reproductive technology—on par with in vitro fertilization—that enabled me to exist, and, now that I do exist, is irrelevant. Being confronted with my donor's identity or any donor siblings would make this fact of my conception bigger than I need it to be, as an adult with a full-blown identity derived from all of my other life experiences. But I still wonder about the minutiae of my ethnicity in much the same way as anyone else who wonders, and feel there's no safe way for me to find out without relinquishing some of my existential independence.
The author and her mom in spring of 1998.
"People obviously want to participate in 23andMe and Ancestry because they're interested in knowing more about themselves," says Shamonki. "I wouldn't want to create a world where people who are donor-conceived feel like they can't participate in this technology because they're trying to shut out [other] information."
After all, it was the allure of that exact conceit—knowing more about oneself—that seemed to magnetically draw in millions of people to these tools in the first place. It's an experience that clearly taps into a population-wide psychic need, even—perhaps especially—if one's origins are a mystery.
For decades, women around the world have made the annual pilgrimage to their doctor for the dreaded but potentially life-saving Papanicolaou test, a gynecological exam to screen for cervical cancer named for Georgios Papanicolaou, the Greek immigrant who developed it.
The Pap smear, as it is commonly known, is credited for reducing cervical cancer mortality by 70% since the 1960s; the American Cancer Society (ACS) still ranks the Pap as the most successful screening test for preventing serious malignancies. Nonetheless, the agency, as well as other medical panels, including the US Preventive Services Task Force and the American College of Obstetrics and Gynecology are making a strong push to replace the Pap with the more sensitive high-risk HPV screening test for the human papillomavirus virus, which causes nearly all cases of cervical cancer.
So, how was the Pap developed and how did it become the gold standard of cervical cancer detection for more than 60 years?
Born on May 13, 1883, on the island of Euboea, Greece, Georgios Papanicolaou attended the University of Athens where he majored in music and the humanities before earning his medical degree in 1904 and PhD from the University of Munich six years later. In Europe, Papanicolaou was an assistant military surgeon during the Balkan War, a psychologist for an expedition of the Oceanographic Institute of Monaco and a caregiver for leprosy patients.
When he and his wife, Andromache Mavroyenous (Mary), arrived at Ellis Island on October 19, 1913, the young couple had scarcely more than the $250 minimum required to immigrate, spoke no English and had no job prospects. They worked a series of menial jobs--department store sales clerk, rug salesman, newspaper clerk, restaurant violinist--before Papanicolaou landed a position as an anatomy assistant at Cornell University and Mary was hired as his lab assistant, an arrangement that would last for the next 50 years.
Papanikolaou would later say the discovery "was one of the greatest thrills I ever experienced during my scientific career."
In his early research, Papanikolaou used guinea pigs to prove that gender is determined by the X and Y chromosomes. Using a pediatric nasal speculum, he collected and microscopically examined vaginal secretions of guinea pigs, which revealed distinct cell changes connected to the menstrual cycle. He moved on to study reproductive patterns in humans, beginning with his faithful wife, Mary, who not only endured his almost-daily cervical exams for decades, but also recruited friends as early research participants.
Writing in the medical journal Growth in 1920, the scientist outlined his theory that a microscopic smear of vaginal fluid could detect the presence of cancer cells in the uterus. Papanikolaou would later say the discovery "was one of the greatest thrills I ever experienced during my scientific career."
At this time, cervical cancer was the number one cancer killer of American women but physicians were skeptical of these new findings. They continued to rely on biopsy and curettage to diagnose and treat the disease until Papanicolaou's discovery was published in American Journal of Obstetrics and Gynecology. An inexpensive, easy-to-perform test that could detect cervical cancer, precancerous dysplasia and other cytological diseases was a sea change. Between 1975 and 2001, the cervical cancer rate was cut in half.
Papanicolaou became Emeritus Professor at Cornell University Medical College and received numerous awards, including the Albert Lasker Award for Clinical Medical Research and the Medal of Honor from the American Cancer Society. His image was featured on the Greek currency and the US Post Office issued a commemorative stamp in his honor. But international acclaim didn't lead to a more relaxed schedule. The researcher continued to work seven days a week and refused to take vacations.
After nearly 50 years, Papanicolaou left Cornell to head and develop the Cancer Institute of Miami. He died of a heart attack on February 19, 1962, just three months after his arrival. Mary continued to work in the renamed Papanicolaou Cancer Research Institute until her death 20 years later.
The annual pap smear was originally tied to renewing a birth control prescription. Canada began recommending Pap exams every three years in 1978. The United States followed suit in 2012, noting that it takes many years for cervical cancer to develop. In September 2020, the American Cancer Society recommended delaying the first gynecological pelvic exam until age 25 and replacing the Pap test completely with the more accurate human papillomavirus (HPV) test every five years as the technology becomes more widely available.
Not everyone agrees that it's time to do away with this proven screening method, though. The incidence rate of cervical cancer among Hispanic women is 28% higher than for white women, and Black women are more likely to die of cervical cancer than any other racial or ethnicities.
Whether the Pap is administered every year, every three years or not at all, Papanicolaou will always be known as the medical hero who saved countless women who would otherwise have succumbed to cervical cancer.
Science Has Given Us the Power to Undermine Nature's Deadliest Creature: Should We Use It?
Lurking among the swaying palm trees, sugary sands and azure waters of the Florida Keys is the most dangerous animal on earth: the mosquito.
While there are thousands of varieties of mosquitoes, only a small percentage of them are responsible for causing disease. One of the leading culprits is Aedes aegypti, which thrives in the warm standing waters of South Florida, Central America and other tropical climes, and carries the viruses that cause yellow fever, dengue, chikungunya and Zika.
Dengue, a leading cause of death in many Asian and Latin American countries, causes bleeding and pain so severe that it's referred to as "breakbone fever." Chikungunya and yellow fever can both be fatal, and Zika, when contracted by a pregnant woman, can infect her fetus and cause devastating birth defects, including a condition called microcephaly. Babies born with this condition have abnormally small heads and lack proper brain development, which leads to profound, lifelong disabilities.
Decades of efforts to eradicate the disease-carrying Aedes aegypti mosquito from the Keys and other tropical locales have had limited impact. Since the advent of pesticides, homes and neighborhoods have been drenched with them, but after each spraying, the mosquito population quickly bounces back, and the pesticides have to be sprayed over and over. But thanks to genetic engineering, new approaches are underway that could possibly prove safer, cheaper and more effective than any pesticide.
One of those approaches involves, ironically, releasing more mosquitoes in the Florida Keys.
The kill-switch will ensure that the female offspring die before they reach maturity and thus, be unable to reproduce.
British biotech company Oxitec has engineered male mosquitoes to have a genetic "kill-switch" that could potentially crash the local population of Aedes aegypti, at least in the short-term. The modified males that are being released are intended to mate with wild females.
Males don't bite; it's the female that's deadly, always seeking out blood to gorge on to help mature her eggs. After settling her filament-thin legs on her prey, she sinks a needlelike proboscis into the skin and sucks the blood until her translucent belly is bloated and glowing red.
The kill-switch will ensure that the female offspring die before they reach maturity and thus, be unable to reproduce. In some experiments using genetically modified mosquitoes, the small number of females that survived were rendered unable to bite. The modification prevented the proboscis, the sickle-like needle that pierces the skin, from forming properly. But this isn't the case with Oxitec's mosquitoes; in the Oxitec release, the females simply die off before they can mate.
The modified mosquitoes are the second genetically engineered insect to be released in the U.S. by Oxitec. The first was a modified diamondback moth, an agricultural pest that doesn't bite humans. But with the mosquitoes, there are many questions about the long-term effects on wild ecosystems, other species in the food chain, and human health. With the Keys initiative, there has been vociferous opposition from environmental groups and some local residents, but some scientists and public health experts say that genetically modified insects pose less of a risk than the diseases they carry and the powerful, indiscriminant pesticides used to combat them.
Oxitec spent a decade developing the technology and engaging in a massive public education campaign before beginning the field test in April. Eventually, the company will release 750,000 of the insects from six locations on three islands of the Florida Keys. Although the release has been approved by the Environmental Protection Agency, the Florida Department of Agriculture and Consumer Services, and the Florida Keys Mosquito Control District, the company was never able to obtain unanimous approval among local residents, some of whom worry that the experiment could cause irreversible damage to the ecosystem.
The company has already begun distributing multiple blue and white boxes containing the eggs of thousands of the mosquitoes which, when water is added, will hatch legions of modified males.
There are a number of techniques available to genetically engineer animals and plants to minimize disease and maximize crop yields. According to Kevin Gorman, chief development officer for Oxitec, the company's mosquitoes were altered by injecting genetic material into the eggs, testing them, then re-injecting them if not enough of the new genes were incorporated into the developing embryos. "We insert genes, but take nothing away," he says.
Gorman points out that the Oxitec mosquitoes will only pass the kill-switch genes on to some of their offspring, and that they will die out fairly quickly. They should temporarily lessen diseases by reducing the local population of Aedes aegypti, but to have a long-term effect, repeated introductions of the altered mosquitoes would have to take place.
Critics say the Oxitec experiment is a precursor to a far more consequential, and more troubling development: the introduction of gene drives in modified species that aggressively tilt inheritance factors in a decided direction.
Gene Drives
Gene drives coupled with the recent development of the gene-editing technique, CRISPR-Cas9, promise to be far more targeted and powerful than previous gene altering efforts. Gene drives override the normal laws of inheritance by harnessing natural processes involved in reproduction. The technique targets small sections of the animal's DNA and replaces it with an altered allele, or trait-determining snippet. Normally, when two members of a species mate, the offspring have a 50 percent chance of receiving an allele because they will receive one from each parent. But in a gene drive, each offspring ends up getting two copies of a desired allele from a single parent—the modified parent. The method "drives" the modified DNA into up to 100 percent of the animals' offspring.
In the case of gene drive mosquitoes, the modified males will mate with wild females. Upon fertilization of the egg, the offspring will start off with one copy of the targeted allele from each parent. But an enzyme, called Cas9, is introduced and acts as a kind of molecular scissors to cut, or damage, the "wild" allele. Then the developing embryo's genetic repair mechanisms kick in and, to repair the damage, copy the undamaged allele from the modified parent. In this way, the offspring ends up with two copies of the modified allele, and it will pass the modification on to virtually all of its progeny.
There is some debate among researchers and others about what constitutes a gene drive, but leaders in the nascent field, such as Andrea Crisanti, generally agree that the defining factor is the heritability of a change introduced into a species. A gene drive is not a particular gene or suite of genes, but a program that proliferates in a species because it is inherited by virtually all offspring.
An illustration of how gene drives spread an altered gene through a population.
Mariuswalter, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0>, via Wikimedia Commons
Of the experts who spoke with Leaps.org for this article, there was disagreement on whether the Oxitec mosquitoes carry a gene drive, but Gorman says they don't because they carry no inheritance advantage. The mosquitoes have baked-in limitations on their potential impact on the tropical ecosystem because the kill-switch should only temporarily affect the local population of Aedes aegypti. The modified mosquitoes will die pretty quickly. But modified organisms that do carry gene drives have the potential to spread widely and persist for an unknown period of time.
Since it has such a reproductive advantage, animals modified by CRISPR and carrying gene drives can quickly replace wild species that compete with them. On the other hand, if the gene drive carries a kill-switch, it can theoretically cause a whole species to collapse.
This makes many people uneasy in an age of mass extinctions, when animals and ecosystems are already under extreme stress due to climate change and the ceaseless destruction of their habitats. Ecosystems are intricate, delicately balanced mosaics where one animal's competitor is another animal's food. The interconnectedness of nature is only partially understood and still contains many mysteries as to what effects human intervention could eventually cause.
But there's a compelling case to be made for the use of gene drives in general. Economies throughout the world are often based on the ecosystem and its animals, which rely on a natural food chain that was evolved over billions of years. But diseases carried by mosquitoes and other animals cause massive damage, both economically and in terms of human suffering.
Malaria alone is a case in point. In 2019, the World Health Organization reported 229 million cases of malaria, which led to 449,000 deaths worldwide. Over 70 percent of those deaths were in children under the age of 12. Efforts to combat malaria-carrying mosquitoes rely on fogging the home with chemical pesticides and sleeping under pesticide-soaked nets, and while this has reduced the occurrence of malaria in recent years, the result is nowhere near as effective as eradicating the Anopheles gambiae mosquito that carries the disease.
Pesticides, a known carcinogen for animals and humans, are a blunt instrument, says Anthony Shelton, a biologist and entomologist at Cornell University. "There are no pesticides so specific that they just get the animal you want to target. They get pollinators. They get predators and parasites. They negatively affect the ecosystem, and they get into our bodies." And it's not uncommon for insects to develop resistance to pesticides, necessitating the continuous development of new, more powerful chemicals to control them.
"The harm of insecticides is not debatable," says Shelton. With gene drives, the potential harm is less clear.
Shelton also points out that although genetic modification sounds radical, people have been altering the genes of animals since before recorded history, through the selective breeding of farm and domesticated animals. While critics of genetic modification decry the possibility of changing the trajectory of evolution in animals, "We've been doing it for centuries," says Shelton. "Gene drives are just a much faster way to do what we've been doing all along."
Still, one might argue that farms are closed experiments, because animals enclosed within farms don't mate with wild animals. This limits the impact of human changes on the larger ecosystem. And getting new genes to work their way through multiple generations in longer-lived animals through breeding can take centuries, which imposes the element of time to ascertain the relative benefits of any introduced change. Gene drives fast-forward change in ways that have never been harnessed before.
The unique thing about gene drives, Shelton says, is that they only affect the targeted species, because those animals will only breed with their own species. Although the Oxitec mosquitoes are modified but not imbued with a gene drive, they illustrate the point. Aedes aegypti will only mate with its own species, and not with any of the other 3,000 varieties of mosquito. According to Shelton, "If they were to disappear, it would have no effect on the fish, bats and birds that feed on them." But should gene drives become widely used, this won't always be true of animals that play a larger part in the food chain. This will be especially true if gene drives are used in mammals.
One factor, cited by both proponents of gene drives and those who want a complete moratorium on them, is that once a gene drive is released into the wild, animals tend to evolve strategies to resist them. In a 2017 article in Nature, Philip Messer, a population geneticist at Cornell, says that gene drives create "the ideal conditions for resistant organisms to flourish."
Sometimes, when CRISPR is used and the Cas9 enzyme cuts an allele soon after egg fertilization, the animal's repair mechanism, rather than creating a straight copy of the desired allele, inserts random DNA letters. The gene drive won't recognize the new sequence, and the change will slip through. In this way, nature has a way of overriding gene drives.
In caged experiments using CRISPR-modified mosquitoes, while the gene drive initially worked, resistance has developed fairly rapidly. Scientists working for Target Malaria, the massive anti-malaria enterprise funded by the Bill and Melinda Gates Foundation, are now working on developing a new version of a gene drive that is not so vulnerable to genetic resistance. But cage conditions are not representative of complex natural ecosystems, and to figure out how a modified species is going to affect the big picture, ultimately they will have to be tested in the wild.
Because there are so many unknowns, such testing is just too dangerous to undertake, according to environmentalists such as Dana Perls of the Friends of the Earth, an international consortium of environmental organizations headquartered in Amsterdam. "There's no safe way to experiment in the wild," she says. "Extinction is permanent, and to drive any species to extinction could have major environmental problems. At a time when we're seeing species disappearing at a high rate, we need to focus on safe processes and a slow approach rather than assume there's a silver bullet."
She cites a number of possible harmful outcomes from genetic modification, including the possible creation of dangerous hybrids that could be more effective at spreading disease and more resistant to pesticides. She points to a 2019 paper in Scientific Reports in which Yale researchers suggested there's evidence that genetically modified species can interbreed with organisms outside their own species. The researchers claimed that when Oxitec tested its modified Aedes aegypti mosquitoes in Brazil, the release resulted in a dangerous hybrid due to the altered animals breeding with two other varieties of mosquito. They suggested that the hybrid mosquito was more robust than the original gene drive mosquitoes.
The paper contributed to breathless headlines in the media and made a big splash with the anti-GMO community. However, it turned out that when other scientists reviewed the data, they found it didn't support the authors' claims. In a short time, the editors of Nature ran an Editorial Expression of Concern for the article, noting that of the insects examined by the researchers, none of them contained the transgenes of the released mosquitoes. Among multiple concerns, Nature found that the researchers didn't follow the released population for more than a short time, and that previous work from the same authors had shown that after a short time, transgenes would have faded from the population.
Of course, unintended consequences are always a concern any time we interfere with nature, says Michael Montague, a senior scholar at Johns Hopkins University's Center for Health Security. "Unpredictability is part of living in the world," he says. Still, he's relatively comfortable with the limited Florida Keys release.
"Even if one type of mosquito was eliminated in the Keys, the ecosystem wouldn't notice," he says. This is because of the thousands of other species of mosquito. He says that while the Keys initiative is ultimately a test, "Oxitec has done their due diligence."
Montague addressed another concern voiced by Perls. The Oxitec mosquitoes were developed so that the female larvae will only hatch in water containing the antibiotic tetracycline. Perls and others caution that, because of the widespread use of antibiotics, the drug inevitably makes its way into the water system, and could be present in the standing pools of water that mosquitoes mate and lay their eggs in.
It's highly unlikely that tetracycline would exist in concentrations high enough to make any difference, says Montague. "But even if it did happen, and the modified females hatched out and mated with wild males, many of their offspring would inherit the modification and only be able to hatch in tetracycline-laced water. The worst-case scenario would be that the pest control didn't work. Net effect: Zero," he says.
As for comparing GMO mosquitoes with insecticides, Montague says, "We 100 percent know insecticides have a harmful effect on human health, whereas modified [male] mosquitoes don't bite humans. They're essentially a chemical-free insecticide, and if there were to be some harmful effect on human health, it would have to be some complicated, convoluted effect" that no one has predicted.
It's not clear, though, given the transitory nature of self-limiting genetically modified insects, whether any effects on the ecosystem would be long-lasting. Certainly in the case of the Oxitec mosquitoes, any effect on the environment would likely be subtle. However, there are other species that are far more important to the food chain, and humans have been greatly impacting them for centuries, sometimes with disastrous effects.
The world's oceans are particularly vulnerable to the effects of human actions. "Codfish used to dominate the North Atlantic ecosystem," says Montague, but due to overfishing, there were huge changes to that ecosystem, including the expansion of their prey—lobsters, crabs and shrimp. The whole system got out of balance." The fish illustrate the international nature of the issues related to gene drives, because wild species have few boundaries and a change in one region can easily spread far and wide.
On the other hand, gene drives can be used for beneficial purposes beyond eliminating disease-carrying species. They could also be used to combat invasive species, fight crop-destroying insects, promote biodiversity, and give a leg up to endangered species that would otherwise die out.
Today nearly 90 percent of the world's islands have been invaded by disease-carrying rodents that have over-multiplied and are driving other island species to extinction. Common rodents such as rats and mice normally encounter a large number of predators in mainland territories, and this controls their numbers. Once they are introduced into island ecosystems, however, they have few predators and often become invasive. Because of this, they are a prevalent cause of the extinction of both animals and plants globally. The primary way to combat them has been to spread powerful toxicants that, when ingested, cause death. Not only has this inhumane practice had limited impact, the toxicants can be eaten by untargeted species and are toxic to humans.
The Genetic Biocontrol of Invasive Rodents program (GBIRd), an international consortium of scientists, ethicists, regulatory experts, sociologists, conservationists and others, is exploring the possible development of a genetically modified mouse that could be introduced to islands where rodents are invasive. Similar to the Oxitec mosquitoes, the mice would carry a modification that results in the appearance of only one sex, and they would also carry a gene drive. Theoretically, once they mate with the wild mice, all of the surviving offspring would be either male or female, and the species would disappear from the islands, giving other, threatened species an opportunity to revive.
GBIRd is moving slowly by design and is currently focused on asking if a genetically engineered mouse should be developed. The program is a potential model for how gene drives can be ethically developed with maximum foresight and the least impact on complex ecosystems. By first releasing a genetically engineered mouse on an island — likely years from now — the impact would naturally be contained within a limited locale.
Regulating GM Insects
While multiple agencies in the U.S. were involved in approving the release of the Oxitec mosquitoes, most experts agree that there is not a straightforward path to regulating genetically modified organisms released into the environment. Clearly, international regulation is needed as genetically modified organisms are released into open environments like the air and the ocean.
The United Nations' Convention on Biological Diversity, which oversees environmental issues at an international level, recently met to continue a process of hammering out voluntary protocols concerning gene drives. Multiple nations have already signed on to already-established protocols, but the United States has not and, according to Montague, is not expected to. "The U.S. will never be signatory to CBD agreements because agricultural companies are huge businesses" that may not see them as in their best interests, he says. Bans or limitations on the release of genetically modified organisms could limit crop yields, for example, thereby limiting profits.
Even if every nation signed on to international regulations of gene drives, cooperation is voluntary. The regulations wouldn't prevent bad actors from using the technology in nefarious ways, such as developing gene drives that can be used as weapons, according to Perls. An example would be unleashing a genetically modified invasive insect to destroy the crops of enemy nations. Or the releasing of a swarm of disease-carrying insects. But in this scenario, it would be very hard to limit the genetically modified species to a specific environment, and the bad actors could be unleashing disaster on themselves.
Because of the risks of misuse, scientists disagree on whether to openly share their gene drive research with others. But Montague believes that there should be a universal registry of gene drives, because "one gene drive can mess up another one. Two groups using the same species should know about each other," he says.
Ultimately, the decision of whether and when to release gene drives into nature rests with not one group, but with society as a whole. This includes not only diverse experts and regulatory bodies, but the general public, a group Oxitec spent considerable time and resources interacting with for their Florida Keys project. In the end, they gained approval for the initiative by a majority of Keys residents, but never gained a total consensus.
There's no escaping the fact that the use of gene drives is a nascent field, and even geneticists and regulators are still grapping with the best ways to develop, oversee, regulate, and control them. Much more data is needed to fully ascertain its risks and benefits.
Experts agree that the Oxitec venture isn't likely to have a noticeable effect on the larger ecosystem unless something truly catastrophic goes wrong. But following the GMO mosquitoes over time will give scientists more real-world data about the long-term effects of genetically altered species. If the release doesn't work, nothing about the ecosystem will change and Aedes aegypti will continue to be a menace to human health. But if something goes horribly wrong, it could hinder the field for years, if not forever.
On the other hand, if the Oxitec mosquitoes and other early initiatives achieve their goals of reducing disease, increasing crop yields, and protecting biodiversity, in the words of Anthony Shelton, "Maybe, 25 to 50 years from now, people will wonder what all the fuss was about."
Correction: The original version of this article mistakenly stated that the modified Oxitec mosquitoes would not be able to form a proper proboscis to bite humans. That is true for some modified mosquitoes but not the Oxitec ones, whose female offspring die off before they reach maturity. Additionally, the Oxitec release was not approved by the FDA and CDC, as originally stated. The FDA and CDC withdrew their role and passed the oversight to other regulatory entities.