More de-extinction (or less extinction?) March 18, 2013Posted by Cameron Shelley in : STV203 , comments closed
A recent posting discussed Stewart Brand’s case for de-extinction, the resurrection of extinct species through the application of genetic (and other) technologies. The idea seems to be taking on meme-like qualities, as a number of other recent pieces have treated the same topic.
For example, this brief article on Wired Science poses the question: “Which species should they bring back to life?” Mug shots of some of the obvious candidates are provided, e.g., the dire wolf (popular to due its graphics-intensive appearance on Game of Thrones), the dodo (poster child of extinct species), and the wooly mammoth. Other possibilities would include extinct humans, e.g., Neandertals and the so-called hobbits.
Researchers, it appears, are not waiting for public input. A group of Australian biologists with the aptly-named Lazarus Project have cloned an extinct frog called Rheobatrachus silus, famous for brooding its eggs in its stomach and giving birth to its young through its mouth. Plagues of resurrected frogs are not yet on their way because no embryos from the cloning process have yet survived. However, that time may be coming soon:
“We’re increasingly confident that the hurdles ahead are technological and not biological and that we will succeed. Importantly, we’ve demonstrated already the great promise this technology has as a conservation tool when hundreds of the world’s amphibian species are in catastrophic decline,” [says the leader of the Lazarus Project team, Professor Mike Archer, of the University of New South Wales, in Sydney.]
The article goes on to say that researchers are looking to de-extinct species such as the woolly mammoth, dodo, Cuban red macaw and New Zealand’s giant moa.
So, what are your picks?
(Lesueur’s tree frog by Fir0002/Wikimedia commons)
Stewart Brand on de-extinction March 14, 2013Posted by Cameron Shelley in : STV203 , comments closed
Have a look at this recent TED talk by the irrepressible Stewart Brand. His topic is “de-extinction”, the resurrection (if you like) of extinct animals by the application of genetic and other technologies.
The idea is indeed a compelling one. Imagine getting back such iconic, extinct animals such as the passenger pigeon, the Tasmanian tiger, or even the wooly mammoth!
Of course, such a project raises some interesting difficulties. A couple are raised at the end of the video:
- Would such a project constitute “playing God”, that is, perhaps, arrogantly messing with nature? Brand’s response is to point out that we have already done so, which is precisely how the situation at hand arose. Whether or not that makes another act of playing God advisable remains unclear.
- Would there be unintended consequences? Perhaps the passenger pigeon or another
resurrectedde-extincted species would displace an established species that people are fond of. Perhaps these new/old species would qualify as invasive species in the world as it exists today. Brand admits that this outcome is one that must be faced.
Another problem alluded to in the talk is that de-extinction technology might be used as an argument against conservation: Who cares if the white rhino goes extinct? We can always de-extinct it later if we want to.
Finally, not everyone interested in novel species may share Brand’s nostalgia for past ecosystems. We already have GloFish and other novelty animals as fruits of genetic engineering. People may become more interested in stocking nature with glo-yotes or mockingjays that scream commercial jingles than in thylacines or Carolina parakeets. Of course, extinct relatives of existing creatures may typically be easier to engineer, but once we get going, where do we stop?
Evolution in the human mouth February 22, 2013Posted by Cameron Shelley in : STV202, STV203 , comments closed
A pair of new articles in Science suggest and interesting story about the evolution of bacteria that live in the human mouth (registration required). In brief:
Some microbes that had lurked at low levels in the mouths of hunter-gatherers bloomed on the sugary films coating the teeth of farmers who munched cereal grains. Eventually the cavity-causing Streptococcus mutans, for one, took root. It adapted to the sweet life, multiplying like a weed and edging out many other species of bacteria. That leaves the modern mouth a depauperate ecosystem, according to two new genetic studies.
One study analyzed the DNA of microbes found in the tartar of ancient human teeth. By analyzing the relative population sizes of different bacteria in these teeth, Alan Cooper and colleagues were able to identify the point in time at which the cavity-causing Streptococcus mutans become the dominant member of the human oral fauna. Their study suggests that this event occurred around 10,000 years ago, at the point when agriculture was developed. The starchy sugars present in grainy foods allowed S. mutans to expand its domain at the expense of other critters less well adapted to feed on the new nutriment.
Omar Cornejo et al. took a different tack, analyzing the distribution of DNA variants in modern mouths and arrived at a very similar result. It seems that the introduction of agricultural technology brought about fundamental changes not just in human nutrition but in our oral health.
The story continues with the development of refined sugars during the Industrial Revolution:
Modern samples and preliminary data from the mid-19th century show an oral environment even more dominated by S. mutans. Cooper concludes that the change occurred with the Industrial Revolution, about 1850 in England, when cavities also increased and refined sugars entered the diet. “Sugar and flour caused everything to go berserk,” he says.
This story amplifies earlier work showing how the development of food technology affects the human form, such as dental occlusion. Modern, processed foods tend to be soft, requiring less chewing and, apparently, leaving our lower mandibles under-developed.
One result of this change in diet has been the development of dentistry and dental technology. All the cavities and other problems created by soft, sugary foods result in a need for special, oral hygiene and the technology to provide it. So, next time you pick up your toothbrush, spare a thought for your predecessors, who planted the seeds of modern, oral hygiene all those years ago.
(Henrik Abelsson Abelsson/Wikimedia commons)
Genetics and intelligence February 19, 2013Posted by Cameron Shelley in : STV203 , comments closed
The Wall Street Journal has an interesting story on a Chinese company that is searching for the genetic basis of intelligence. The Beijing Genomics Institute (BGI) is trying to sign up geniuses, that is, people with an IQ of 160 or more, to donate their genes for analysis. The idea is to determine what genetic components the geniuses have in common that distinguish them from the rest of the population. The project is being led by Zhao Bowen from BGI’s facility in Hong Kong.
(National Institutes of Health/Wikimedia commons)
As the article notes, the genetic basis for intelligence is not well understood. Although some genetic conditions are known to be detrimental to intelligence, genetic factors that support exceptional intelligence remain elusive. The point of the research is to track down these factors.
Of course, such a project can raise concerns. The first is on the appropriateness of the “intelligence” construct. What IQ tests actually measure is disputed, as noted in this recent piece in Science:
Kids who score higher on IQ tests will, on average, go on to do better in conventional measures of success in life: academic achievement, economic success, even greater health, and longevity. Is that because they are more intelligent? Not necessarily. New research concludes that IQ scores are partly a measure of how motivated a child is to do well on the test. And harnessing that motivation might be as important to later success as so-called native intelligence.
The piece goes on to note that, according to psychologist Richard Nisbett, “differences in IQ scores largely disappear when researchers control for social and economic factors.” Whatever difference is found in the BGI study, it may be a false positive, that is, a genetic difference that has nothing to do with intelligence.
Another concern is what might be done with the results of such a study. According to Zhao, the practical upshot would be to use the results to identify intelligent children and to help ensure that they receive an adequate education, one that allows them to capitalize on their gift. However, would the results be used to deny opportunities to children who do not fit the genetic profile, even though they would profit from them? Worse, genetic results could be used to discriminate against people or ethnic groups thought to lack favourable genes.
Of course, it could be that a study, properly designed, might turn up a surprise. A recent observational study in Australia, for example, suggests that genetics is not an important factor in risk of breast cancer in women:
Analysis of the breast screens of almost 20,000 women over two decades shows 72 per cent of women who got breast cancer had no family history of the disease.
The findings contradict the popular belief that genetics plays a key role in determining which one in nine women will get breast cancer.
Perhaps the “risk” of superior intelligence follows a similar pattern, in spite of expectations to the contrary.
DNA gun January 24, 2013Posted by Cameron Shelley in : STV203 , comments closed
From the Huffington Post comes the interesting news that a British firm “SelectaDNA” has designed a “DNA gun”. At first, you might think a DNA gun would extract some of the target’s DNA and capture it for analysis. Instead, this DNA gun actually tags the target with synthetic DNA. The tagged person can then be identified later by detecting the synthetic DNA on them. The idea is for police to use the gun as a way of tagging miscreants during a melee for apprehension at a later and more convenient time.
Tagging people for later arrest is not a new tactic. In the past, police have inserted dye into water then sprayed into crowds of rioters by water canons. On other occasions, police have used paintballs to tag people for later inquiries. I suppose that DNA pellets have the advantage that they do not make a mess, and sympathizers will not be able to smear themselves with the synthetic DNA in solidarity with tagged rioters.
The bright orange colour of the gun is meant, I guess, to emphasize that it is not a weapon. Even so, the act of drawing and aiming the device will no doubt be viewed as an act of aggression by both the wielder and the target.
Natural foods November 23, 2012Posted by Cameron Shelley in : STV203 , comments closed
There is a nice article by Daniel Engber at Slate on the topic of what makes a food “natural” or not. The issue arises in the context of a lawsuit by a Colorado woman against Pepperidge Farms alleging that the description on the package describing Cheddar Goldfish Crackers as “natural” is misleading. More specifically, her complaint is that the soy in the product is genetically modified. Thus, it contains genes that would not “normally” be present.
Engber does a good job of analyzing the problems with the term “natural” when applied to food. If “natural” means the opposite of “artificial”, then any processed food would not be natural. That would include Goldfish Crackers for sure but also Annie’s organic Cheddar Bunnies. These foods would be considered artificial because they are made through a mechanized process, so anything not hand-made would not be considered natural.
Of course, you could go further if you insist that “artificial” excludes anything that is hand-made also. Thus, the hand-made sushi, pasta, and salsa that you might find in the gourmet section of the grocery store would have to be considered unnatural on this definition. Only unprocessed fruits, nuts, and vegetables would qualify. If this is your standard of “natural” (and why not?), then you should shop at a farmers’ market.
As Engber points out, “artificial” could be pushed even further to denote all the products of domestication. Thus, apples, wheat, and chicken, among other items, would not be considered natural. All of these are the fruits, if you like, of artificial selection, thus making them artificial as well. On this view, the only natural foods are those that are “wild”, that is, picked or shot in the open (unless shooting and skinning count as processing, which they might).
The US FDA has consistently declined to define “natural”, as Engber notes. About 20 years ago, the agency issued “an advisory opinion—as opposed to a binding regulation—saying only that natural foods are those that lack ‘artificial or synthetic’ additives.” Of course, this approach is of no use. It says that a product is natural so long as none of its parts are artificial, a circular definition. However, this definition speaks to the main concern of the FDA, which has been with the authenticity of foods. A hamburger is not a “true” hamburger, I would say, if it contains chicken as well as beef. Calling a chicken-burger a hamburger would indeed be misleading. Since authenticity has nothing to do with naturalness, the FDA sees little point in regulating the latter term.
In this case, it seems useless to define “natural” in opposition to “artificial”. I imagine that the notion of “natural” in play here is in opposition to “technology”, where “technology” means “whatever was invented after I grew up.” Since GE crops for agriculture have been around for only a decade or two (at a large scale), they are not “natural” for many folks. Clearly, this definition is not useful for labeling purposes, since what would be natural for one person would not be natural for another. Instead, this definition reveals not luddism but a cautious attitude towards new things.
Where do these considerations leave us? Given all of its senses, the term “natural” is a confusing one. Perhaps it should be banned from food descriptions universally for that reason. After all, we do have more accurate alternatives such as “authentic”, “hand-made”, or “wild” that are somewhat clearer. It might also be an idea to come up with a system that describes, in broad terms, the technologies used to process a given food. That could be educational, as people are often surprised to find out how their food is made.
Parents and offspring in the biotech era October 30, 2012Posted by Cameron Shelley in : STV203 , comments closed
I have commented several times here on the difficulties for family concepts raised by biotechnology. The New York Times has an interesting article related to this topic, concerning a women who is prohibited, for now, from being named the mother of her child.
The woman and her husband entered into a surrogacy arrangement, due to her infertility. The couple arranged in advance to have a judge declare her to be the mother of the child, and to be recorded as such on the child’s birth certificate. A hospital worker, not knowing how to implement the order, queried the New Jersey bureau of vital statistics, which called the Attorney General’s office, which sued to have the arrangement overturned. The State won the suit, which the State Supreme Court has now declined to overturn. Thus, the mother’s best legal option is to become the stepmother of the child she has already been raising for three years.
The State intervened in the case apparently because they were unhappy to see the surrogate mother’s rights set aside by a court order in this way. Interestingly, the law allows for the biological father, that is, sperm donor, to surrender his parental rights fairly straightforwardly. The gestational mother’s rights, however, are a different matter. The couple argued that this distinction in law between sperm donors and surrogate mothers is discriminatory against women. However, the court ruled, in effect, that being a gestational mother is simply different than being a mere sperm donor:
A sperm donor, the court said, lacks the “temporal, physical and emotional investment” that builds as a woman carries a child for nine months.
Certainly, a man’s biological investment in gestation is minimal when compared to a woman’s investment. Still, it does not follow that those rights are inalienable. Yet, the laws of the State do not pronounce clearly on the matter. Legislation to handle such cases was passed by the State legislature but vetoed by the governor, seemingly on the grounds that the law would be precipitous.
Turning to another item, an article in Nature describes technology that can be used to conduct a mitochondrial DNA swap within an embryo during IVF. During the procedure, mitochondrial DNA from a donor is substituted for mitochondrial DNA of the embryo, originating with the mother. The point of this procedure would be to substitute “healthy” mitochondrial DNA for defective DNA, so as to avoid the risk of conditions, such as MS, associated with mitochondrial DNA issues.
Permission from the US FDA to proceed with this research may take a while to obtain. The procedure would create an embryo that is, in genetic terms, descended from perhaps three individuals, that is, a nuclear DNA mother and father, and a mitochondrial DNA parent. It is unclear how such an arrangement would stand under US law.
As ever, biotechnology challenges the notions of family that are enshrined in law. IVF allows technologists to pick apart roles that were bound up together as a result of our evolutionary and cultural history. Perhaps, someday, it will not be noteworthy for a child to have an odd number of parents.
Rodent genes October 19, 2012Posted by Cameron Shelley in : STV203 , comments closed
Rodents have long been sought after by researchers who are interested in their genes. The “knockout mouse“, for example, is a rodent in which a gene has been deactivated in order to observe the consequences of its absence. From these observations, researchers try to infer the function of the deactivated gene.
Now comes news that researchers at Hunter College have engineered mice with special DNA that makes them extremely sensitive to the smell of TNT:
Charlotte D’Hulst, a molecular neurobiologist at Hunter College who presented her work at a meeting of the Society for Neuroscience, used genetic modification to ensure that the mice have 10,000 to 1,000,000 odor-sensing neurons with a TNT-detecting receptor compared with only 4,000 in a normal animal, “possibly amplifying the detection limit for this odor 500-fold,” she says.
The aim is to employ these “hero mice” as a means of detecting landmines, which use TNT as a major component. The idea seems to be to release the mice in a field where landmines are present, track their movements with transponders, and wait for the mice to have seizures. Apparently, the mice are so sensitive to the smell of TNT that actually encountering its odor would result in convulsions.
Whether or not this method will work, I do not know. I suppose it is better to have mice with seizures than people killed or dismembered by landmine explosions.
In other news, scientists have found “super rats”, that is, rats that are resistant to rat poison. By analyzing DNA samples from around the UK, British researchers have discovered that the prevalence of rats with genetic mutations allowing them to survive poisoning is higher than expected:
The highest prevalence has so far been found in certain areas of South of England and West Country where greater than 70 % the animals tested are of the ’super’ rat type.
The mutation is one that occurs naturally but that has spread throughout the rat population in response to the selection pressure exerted by the use of rat poison.
The spread of these mutations could mean more trouble with rat-borne diseases and other problems. Of course, there are more potent poisons that can be used to control rats, but they must be used more carefully and in more controlled conditions than conventional poisons.
So, genetics brings us both life-saving “hero mice” and menacing “super rats”. Perhaps the moral of this situation is one of humility: Whatever control over genetics we gain, some will remain out of reach.
Canada honours eugenics advocate October 9, 2012Posted by Cameron Shelley in : STV203 , comments closed
The Ottawa Citizen reports that the Conservative government has been caught unawares after it unveiled a plaque to honour Dr. Helen MacMurchy on Friday. Dr. MacMurchy was being recognized for her role in the development of the health care system in Canada. The Canada Public Health Association notes her achievements as a public servant:
In 1906, Dr. MacMurchy was appointed Inspector of the Feeble-minded in the Department of the Provincial Secretary in Ontario and took an active interest in education, public charities and child welfare. In 1920, … Dr. MacMurchy was selected as the Director of the Division of Child Welfare.
The synopsis does not note her importance in promoting eugenics in Canada. In 1920, Dr. MacMurchy published The Almosts: a study of the feeble-minded, in which she explained problems such as venereal disease, alcoholism, crime, tuberculosis, illegitimacy, etc. as the results of mental deficiency. To save the nation from being overwhelmed by “degenerate babies”, Dr. MacMurchy advocated for the restriction of immigration and the sterilization of the feeble-minded. Regrettably, such views became popular enough that mandatory eugenical policies were adopted into law in Alberta and British Columbia, resulting in the forced sterilization of thousands.
Not surprisingly, the government is reconsidering its actions:
Rob Taylor, [Environment Minister Peter] Kent’s communications director, said the plaque unveiling “would never have gone forward” had the minister’s office known about MacMurchy’s advocacy of eugenics. “We would certainly not be celebrating somebody whose life work included this dark part of our public policy in the past.”
The episode is more evidence of Canada’s cultural amnesia when it comes to its historical promotion of eugenics. Despite the publicity attached to cases such as Leilani Muir in 1995, who successfully sued the Alberta government over her forced sterilization of 1959, the news that Canada was so accepting of eugenics remains a surprise for many.
Indeed, the article exposing the fumble over the legacy of Dr. MacMurchy misstates the longevity of eugenics in Canada:
Joy Smith, the Manitoba Tory MP who unveiled the plaque at Tunney’s Pasture on behalf of Environment Minister Peter Kent, called on the government not to install it after a Citizen story outlined Dr. Helen MacMurchy’s leading role as an advocate for eugenics, a type of scientific racism that flourished between 1865 and 1945.
Although eugenics did decrease in popular favour after World War II, the case of Leilani Muir in 1959 suggests that support did not end at that time. In fact, application of the Alberta Sexual Sterilization Act of 1928 actually increased in intensity until about 1970, and was repealed only in 1972.
It is not surprising that this history tends to remain overlooked or forgotten. No one likes to be reminded of regrettable national policies. However, ignorance of this history is just as regrettable. Issues concerning immigration policy and genetic technology confront Canada in the 21st Century. In facing these issues, we would do well not to forget our mistakes in the past.
Parents and surrogate parents October 4, 2012Posted by Cameron Shelley in : STV203 , comments closed
A recent article in the Telegraph tells the tale of a British couple who arranged for an Indian woman to be surrogate mother to their children. The couple had made arrangements with an Indian clinic in Hyderabad for a woman there to carry their child. An egg from an unnamed donor was fertilized with the sperm from one of the couple, which was then implanted in the surrogate in India. In the event, early in 2011, the surrogate gave birth to twins.
However, for the couple to take legal custody of the children in Britain, the surrogate mother is required to give her consent. This proved to be impossible: The clinic itself failed to provide the appropriate form, for reasons that remain unclear. A demand for the completed form was sent to the clinic:
However, the only response they received was a DHL package contaning a single sheet of paper with an ‘obscene gesture’ printed on it.
The couple travelled to India to locate the surrogate mother by search. However, she had apparently moved from her last known location, and none of the neighbors knew to where she had gone. Perhaps she used her payment to relocate to a neighborhood that she liked better. Or perhaps she left to outrun the stigma that sometimes attaches to surrogate mothers in India. Whatever the case, the surrogate was not to be found.
In a way, this resolved the legal issue. The British judge granted the couple “parental orders”, observing that they had taken all reasonable steps to obtain the surrogate’s written consent. Certainly, her disappearance suggests a lack of interest in maintaining any contact or rights over the children.
The judge notes that the tale serves as a caution about the “pitfalls” of surrogate parenting arrangements, particularly in the globalized baby business. One point that I find interesting was the assumption in the law that the surrogate mother, by default, enjoys maternal rights over the children she carries. Recall that the surrogate in this case was not the egg donor. So, she was not genetically related to the children she bore. Nevertheless, according to the judge, “the act of carrying and giving birth to a baby establishes a relationship with the child which is one of the most important relationships in life.” The importance of this relationship is not a novel observation. However, the idea that carrying and giving birth to a child, in the absence of a genetic relationship, creates a legal bond is a novel offspring of our new fertility technologies.