Most of you have probably seen this stylized graphic somewhere along the away (I think it was on PBS at some point). But it’s still cool….
April 10, 2012
July 14, 2011
I really love the fact that I live in the early 21st century for a host of reasons. That being said, one aspect that’s certainly true is that when it comes to charismatic natural variety and geography there are very few “blank spots” on the map. You can get a sense of what I’m talking about if you browse National Geographic from the early 20th century. Most of the map had been filled in, but there were still nooks and crannies waiting to be illuminated. So I always find stories like this interesting, because they capture a sliver of the wonder that once was so commonplace, Snow Leopard Population Discovered in Afghanistan:
The Wildlife Conservation Society has discovered a surprisingly healthy population of rare snow leopards living in the mountainous reaches of northeastern Afghanistan’s Wakhan Corridor, according to a new study.
The paper is in the International Journal of Environmental Studies, Saving threatened species in Afghanistan: snow leopards in the Wakhan Corridor:
The Wakhan Corridor in northeast Afghanistan is an area known for relatively abundant wildlife and it appears to represent Afghanistan’s most important snow leopard landscape. The Wildlife Conservation Society (WCS) has been working in Wakhan since 2006. ...
June 28, 2011
In the comments below Antonio pointed me to this working paper, What Do DNA Ancestry Tests Reveal About Americans’ Identity? Examining Public Opinion on Race and Genomics. I am perhaps being a bit dull but I can’t figure where its latest version is found online (I stumbled upon what looks like another working paper version on one of the authors’ websites). Here’s the abstract:
Genomics research will soon have a deep impact on many aspects of our lives, but its political implications and associations remain undeveloped. Our broad goal in this research project is to analyze what Americans are learning about genomic science, and how they are responding to this new and potentially fraught technology.
We pursue that goal here by focusing on one arena of the genomics revolution — its relationship to racial and ethnic identity. Genomic ancestry testing may either blur racial boundaries by showing them to be indistinct or mixed, or reify racial boundaries by revealing ancestral homogeneity or pointing toward a particular geographic area or group as likely forebears. Some tests, or some contexts, may permit both outcomes. In parallel fashion, genomic information about race ...
May 25, 2011
I’ve been taking about ‘meat things’ for nearly 10 years, so I was really excited by the new Michael Specter piece in The New Yorker about artificially grown meat, Test-tube Burgers. You can’t read most of it online, so I want to copy this small section:
…One study, completed last year by researchers at Oxford and the University of Amsterdam, reported that the production of cultured meat could consume roughly half the energy and occupy just two percent of the land now devoted to the world’s meat industry….
I say real factories because we are all aware I assume by this point of the nature of ‘factory farming’. But mass production of animal stock is an ad hoc kludge. Domesticated animals have been bred for meat production, but they remain organisms with all the range of activities and ends which the term ‘organism’ entails. Raising raw tissue in cultures may seem ‘yucky,’ a point Specter covers in assessing the reaction of some environmentalists and animal-rights activists who don’t seem as excited by the shift from conventional livestock raising to growing tissue as one would expect if they ran the numbers, but it is probably inevitable if it is feasible. ...
On DNA Day, 23 and Me had a sale on their personal genomics service. They’d do their standard scan of your genome for free, as long as you paid for a year’s worth of their online subscription service.
For the price (nearly free up front, and a modest cost for the online community provided), my wife and I jumped on the deal. Since I got the results back two weeks ago, I’ve been exploring not only the services and information provided by 23 and Me, but the various other tools that individuals have started producing to help analyze and investigate this insight into my ubiquitous but invisible DNA.
My genome, for instance, revealed a genetic predisposition towards late-onset Alzheimers. The odds of getting Alzheimers are still quite small, but elevated because of this particular mutation to the APOE4 gene. This wasn’t a total surprise, given my family history, and as a healthy, young guy with a background in biology and biostatistics, it wasn’t hard for me to put that information into a context and move on. Down the road, I’ll ...
May 19, 2011
The title above basically describes the message of evolutionary biologist Mike Lynch from what I can gather. His basic argument is outlined in long form in The Origins of Genome Architecture, though the outline of the thesis is evident over 10 years back (see Preservation of Duplicate Genes by Complementary, Degenerative Mutations). Verbally I think the easiest way to explain Lynch’s framework is that in species with small effective population sizes the creativity of stochastic forces in generating non-adaptive structure and complexity tends to overwhelm the power of natural selection to prune this tendency toward baroque. I reviewed a paper last year which argued that Lynch’s observation of an inverse relation between effective population and genome size was an artifact, that once you controlled for phylogenetic history it disappeared. Suffice it to say this is an area of dispute and active research, so we shouldn’t take any individual’s word for it. This is science on the broadest canvas. Extraordinary general claims need to backed ...
February 8, 2011
Link to review: The Price of Altruism.
Link to review: The wisdom of Seinfeld.
Link to review: The wisdom of Seinfeld.
John Hawks and Jerry Coyne are mooting the ‘species concepts’ debate, with particular focus on recent human origins (specifically, the relationship of modern humans to Neandertals and Denisovans). Coyne, who coauthored the book Speciation and remains preoccupied with the issue in his academic work, knows of what he speaks. And of course he wouldn’t think that the discussion of species, how to delineate them, and what they are, is a sterile exercise. He has chosen to allocate a significant portion of his life to the topic. I think very few would disagree with Coyne when he contends that “Species are not arbitrary divisions of an organic continuum.” If there is one taxonomic category which has a concrete basis in reality, that would seem to be species. But, I would observe that I’m not sure that species are necessarily so clear and distinct. After all, we know that there is here and there, but where does here end, and there begin?
I’m of a reminded of the classic Zeno’s paradox:
In the paradox of Achilles and the Tortoise, Achilles is in a footrace with the tortoise. Achilles allows the tortoise a head start of 100 metres. If ...
February 4, 2011
February 3, 2011
Link to review: Pandora’s Seed: The Unforeseen Cost of Civilization
Link to review: Mother Nature: a complicated and morally ambivalent tale
Link to review: Mother Nature: a complicated and morally ambivalent tale
December 13, 2010
This morning I received an email from the communication director of the American Anthropology Association. The contents are on the web:
AAA Responds to Public Controversy Over Science in Anthropology
Some recent media coverage, including an article in the New York Times, has portrayed anthropology as divided between those who practice it as a science and those who do not, and has given the mistaken impression that the American Anthropological Association (AAA) Executive Board believes that science no longer has a place in anthropology. On the contrary, the Executive Board recognizes and endorses the crucial place of the scientific method in much anthropological research. To clarify its position the Executive Board is publicly releasing the document “What Is Anthropology?” that was, together with the new Long-Range Plan, approved at the AAA’s annual meeting last month.
The “What Is Anthropology?” statement says, “to understand the full sweep and complexity of cultures across all of human history, anthropology draws and builds upon knowledge from the social and biological sciences as well as the humanities and physical sciences. A central concern of anthropologists is the application of knowledge to the solution of human problems.” Anthropology is a holistic and expansive discipline that covers the full breadth of human history and culture. As such, it draws on the theories and methods of both the humanities and sciences. The AAA sees this pluralism as one of anthropology’s great strengths.
Changes to the AAA’s Long Range Plan have been taken out of context and blown out of proportion in recent media coverage. In approving the changes, it was never the Board’s intention to signal a break with the scientific foundations of anthropology – as the “What is Anthropology?” document approved at the same meeting demonstrates. Further, the long range plan constitutes a planning document which is pending comments from the AAA membership before it is finalized.
Anthropologists have made some of their most powerful contributions to the public understanding of humankind when scientific and humanistic perspectives are fused. A case in point in the AAA’s $4.5 million exhibit, “RACE: Are We So Different?” The exhibit, and its associated website at www.understandingRACE.org, was developed by a team of anthropologists drawing on knowledge from the social and biological sciences and humanities. Science lays bare popular myths that races are distinct biological entities and that sickle cell, for example, is an African-American disease. Knowledge derived from the humanities helps to explain why “race” became such a powerful social concept despite its lack of scientific grounding. The widely acclaimed exhibit “shows the critical power of anthropology when its diverse traditions of knowledge are harnessed together,” said Leith Mullings, AAA’s President-Elect and the Chair of the newly constituted Long-Range Planning Committee.
Up until the last paragraph this is an anodyne statement. Who could disagree with: “Anthropology is a holistic and expansive discipline that covers the full breadth of human history and culture. As such, it draws on the theories and methods of both the humanities and sciences. The AAA sees this pluralism as one of anthropology’s great strengths.” But the explosion of anger from biologically and scientifically oriented anthropologists on the web is drawn from a deeper layer of lived experience. On a raw level many of them feel that some factions in cultural anthropology are obscurantists who are fluent in rhetoric which they utilize in power-plays and politics. There are anthropologists who do deny the deep insights of the scientific method in illuminating reality. In fact, they reject the naive realism at the heart of science as it is practiced. For them science is a swear-word, and connotes an affinity with oppression and all the negative abstractions in fashion at a given time (e.g., patriarchy, heternormativity, capitalism, Eurocentrism, etc.). Of course as I note above scientific anthropologists are not given to tolerating the verbal circumlocutions and incantations of their non-scientific colleagues with much grace themselves. There is a deep cultural chasm, and these sorts of arguments over words in obscure institutional documents are only triggers for a persistent roiling debate.
As for the last paragraph, it illustrates the selectivity of a discipline which attempts to contextualize, and often has a skeptical relationship toward a positive framework. I believe that race is a social construct. The Hispanic identity, which consists of people of indigenous Amerindian, European, and African ancestry, and all their combinations, has been racialized. The Islamic identity has also been racialized. Benjamin Franklin stupidly contended that only the English and Saxons were true whites, with all other Europeans, including Nordics, being swarthy.
But just because a construct has a social element does not mean it has only a social construct. Because of the Left-liberal anti-racist egalitarian bias of anthropology, the academy in general, and the dominant narrative of Western society as a whole, there is a strong tendency to assert flatly that “race does not exist” as a biological concept. There is no interrogation of the concept of race except to refute its utility. This is not a case of agnostic skepticism washing away illusions, but a case of skepticism applied in a fashion to obtain a clear and distinct objective result which corresponds to reality. When it comes to race many become naive realists who accept that biological concepts can be falsified or verified in a simple and straightforward fashion. There is all of a sudden one Way of Knowing which presents us with indubitable truths.
Here is L. L. Cavalli-Sforza (my question in italics):
7) Question #3 hinted at the powerful social impact your work has had in reshaping how we view the natural history of our species. One of the most contentious issues of the 20th, and no doubt of the unfolding 21st century, is that of race. In 1972 Richard Lewontin offered his famous observation that 85% of the variation across human populations was within populations and 15% was between them. Regardless of whether this level of substructure is of note of not, your own work on migrations, admixtures and waves of advance depicts patterns of demographic and genetic interconnectedness, and so refutes typological conceptions of race. Nevertheless, recently A.W.F. Edwards, a fellow student of R.A. Fisher, has argued that Richard Lewontin’s argument neglects the importance of differences of correlation structure across the genome between populations and focuses on variance only across a single locus. Edwards’ argument about the informativeness of correlation structure, and therefore the statistical salience of between-population differences, was echoed by Richard Dawkins in his most recent book. Considering the social import of the question of interpopulational differences as well as the esoteric nature of the mathematical arguments, what do you believe the “take home” message of this should be for the general public?
Edwards and Lewontin are both right. Lewontin said that the between populations fraction of variance is very small in humans, and this is true, as it should be on the basis of present knowledge from archeology and genetics alike, that the human species is very young. It has in fact been shown later that it is one of the smallest among mammals. Lewontin probably hoped, for political reasons, that it is TRIVIALLY small, and he has never shown to my knowledge any interest for evolutionary trees, at least of humans, so he did not care about their reconstruction. In essence, Edwards has objected that it is NOT trivially small, because it is enough for reconstructing the tree of human evolution, as we did, and he is obviously right.
L. L. Cavalli-Sforza contends that between population genetic variation is not trivially small. This is clear from the fact that one can discern village-to-village genetic distinctions in Europe. Human variation exists, and it is not trivial. It is useful for phylogenetics, significantly impacts salient phenotypes, and, risks for particular diseases. The social construction of race has real biological raw materials. At one end, the transformation of white European converts to Islam through changes in personal appearance into de facto “People of Color” are matters of social construction in totality. In contrast, the blackness of a Dinka from Sudan is a matter of biological categorization. The categorization of Egyptian Arabs with obvious African admixture as “white” in the US Census is a matter of social construction due to bureaucratic contingency, and illustrates the intersection of biological reality and social fluidity. It is well known that when foreign Arabs with obvious black admixture visited the American South there was often a debate as to whether they were subject to segregation, illustrating the tensions between social norms (which would have coded them as black), bureaucratic function (which coded them as non-black usually), and biological reality (where they were an amalgam of a minor black African component with a dominant white Arab component).
Of course it is true that on any given trait variation can span populations. But even in the case given above, of sickle cell, the correlations with ancestry and population are striking. A lower boundary value is that 75% of sickle cell suffers are of mostly African ancestry, despite only 15% of the world’s population being of mostly African ancestry. These statistics refute a platonic model of race, but they do not refute the population-thinking which is at the heart of much of modern biology, pure and applied.
All that said, the word “race” is fraught with a lot of historical baggage. Therefore to study population wide variation you need to focus on “fine-scale population structure” and what not. This trend would be something of interest for cultural anthropologists of science to study. Race is just a word. Even a term as widely accept as species exhibits a fair amount of flexibility on the margins. But the underlying biological patterns, and the instrumental utility of those patterns, can not be denied.
Addendum: I often use “human” or “humankind” where earlier norms would be to use “man” or “mankind.” My main rationale is I don’t want annoying comments objecting to the term. The concept which I’m pointing to is the same no matter the pointer, and so I don’t mind changing it to facilitate my intent to communicate clearly and without undue extraneous baggage.
December 5, 2010
Rosie Redfield has a “must read” post, Arsenic-associated bacteria (NASA’s claims). I won’t excerpt it, read the whole thing. To me it is very interesting that many pieces of her critique are ones I’ve encountered in emails or Facebook postings. She stitches them together into a coherent whole. She’ll be writing a letter to Science. Hopefully they’ll publish it. Even if you don’t have a deep background in microbiology and biochemistry I think it was clear that the authors had jumped to some inferences too quickly.
(Acknowledgement, John Hawks)
Update: Also, Arsenate-based DNA: a big idea with big holes:
So the Sargasso Sea tells us that some bacteria are capable of making DNA at very low phosphate concentrations. The most plausible explanation is that the bacterium GFAJ-1 can make normal DNA at micromolar phosphate concentrations, and that it also has the ability to tolerate very high arsenate concentrations.
This seems like the “boring,” but most plausible, explanation.
Update II: David Dobbs reviews the journalistic response. I think that people who write about science were in a bind because of the structural problems that David points out. When I first skimmed the paper it seemed to claim too much, but I had to keep in mind that it got through peer review. On the other hand as I stated once scientists in a position to critique on a genuinely technical dimension started complaining really loudly on social networking, that changed my own perception really quickly.
November 24, 2010
October 31, 2010
October 12, 2010
John Hawks, Genomes unzipped, unzipped:
What I wonder is, how much will personal genomics be like nude beaches? I mean, it’s been a long time since the first nude beaches, but most people don’t take advantage of the opportunity. Clearly, there’s variation in different countries! But most people neither feel compelled to see others’ data nor feel comfortable sharing their own.
Well, they used the word unzipped, not me!
Obviously John had his tongue-firmly-planted-in-cheek, but I have wondered about this. How deep is the impact of personal genomics going to be for individuals? If a person gets their genome sequenced and has a list of odds ratios in front of them are they going to bone up on the statistical genetic subtleties of the face value?
That is where genetic counselors come in. The necessity of interpretative experts highlights the difference between nude beaches and personal genomics: personal genomics has more potential societal impact. I know of the nudist/naturist phenomenon only tangentially, but it strikes me as similar to the broader New Age health movement. The focus is on individual health returns. A colon cleanse simply does not have much of broader social effect. Yes, lest my nudist readers strike me down I do understand that there are purported positive social externalities, but set next to personal genomics nudism still strikes me as a fundamentally more individual activity whose benefits redound to the naked individuals, and not the broader clothed society. It does not pick my pocket nor break my leg if my neighbor is a weekend nudist. It is of no concern of mine (in contrast, my experience with public nudity is that it is generally disruptive when unexpected).
I conceive of the social returns to personal genomics as a function of the proportion utilizing it will be defined by an s-curve. When only a few people have been genotyped your understanding of population-wide variation is still spotty. But as you increase your coverage you get a better sense of the variance within the population…but soon enough you enter the phase of diminishing returns.
Here’s a concrete example. In Reconstructing Indian History Reich et al. indicated that it is likely that South Asian castes are endogamous groups which will carry their own recessive risk alleles. In other words, Kayasthas from Bengal may have their own suite of recessive diseases, while Nadars from Tamil Nadu may have a totally different set of risk alleles. In a world with infinite NIH funding there would studies of Kayasthas and Nadars, and doctors and genetic counselors would be aware of what to look for in each group. We don’t live in a world with infinite NIH funding. Let’s assume that 1% of Indian Americans are Kayasthas from Bengal. That’s 30,000 people. If 5% of them make extensive use of personal genomics, then you have 1,500 people with a deep individual knowledge of their personal genomic profile, as well as a set of possible diagnoses or suites of symptons.
We’re still at the individual level. How does this matter on a social scale? Because with modern technology people can form communities online and get a sense of the nature of things from the “bottom-up.” Granted, the information gleaned isn’t going to go through peer review, and “irrational herds” can no doubt emerge. The bigger point is that sum can become more than the parts as motivated individuals pool information in a coordinated fashion. Once there’s some general insight extracted then that will flow to the rest of the group because of interpersonal networks.
This already happens with genealogy. A few highly motivated individuals dig deep into the archives to learn about their own personal history, and once they’ve retrieved the information they freely distribute what they’ve found to their relatives. From one perspective you could say that others are “free riding” on the passion and labor of a few, but you could also characterize this as a spillover effect or positive externality. The consequences of personal genomics are arguably much more substantive than traditional genealogy because of their potential health import.
Note that I’m emphasizing the social good here. Your sample size only needs to be so large to get a good sense of population-wide dynamics. More prosaically, as I noted before the Genomes Unzipped bloggers have opened a window into the genetics of their extended families. If Dienekes analysis is correct Joseph Pickrell and Vincent Plagnol likely have half-Jewish parents. Not that there’s anything wrong with that, though some people are still somewhat reluctant to acknowledge their Jewish heritage even today.
I assume that there will be individual utility as whole populations are sequenced over time. There’s more you can potentially learn by getting yourself sequenced even after ethnic-group or family level risks are ascertained (e.g., what are your distinctive alleles which are de novo mutations?). But this would simply be a classic increase of well being through summing of the parts. And here the analogy to the nude beach would be valid.
Image Credit: Pradeur
October 11, 2010
Last month in Nature Reviews Genetics there was a paper, Measuring selection in contemporary human populations, which reviewed data from various surveys in an attempt to adduce the current trajectory of human evolution. The review didn’t find anything revolutionary, but it was interesting to see where we’re at. If you read this weblog you probably accept a priori that it’s highly unlikely that evolution “has stopped” because infant mortality has declined sharply across developed, and developing, nations. Evolution understood as change in gene frequencies will continue because there will be sample variance in the proportions of given alleles from generation to generation. But more interestingly adaptive evolution driven by change in mean values of heritable phenotypes through natural selection will also continue, assuming:
1) There is variance in reproductive fitness
2) That that variance is correlated with a phenotype
3) That those phenotypes are at all heritable. In other words, phenotypic variation tracks genotypic variation
Obviously there is variance in reproductive fitness. Additionally, most people have the intuition that particular traits are correlated with fecundity, whether it be social-cultural identities, or personality characteristics. The main issue is probably #3. It is a robust finding for example that in developed societies the religious tend to have more children than the irreligious. If there is an innate predisposition to religiosity, and there is some research which suggests modest heritability, then all things being equal the population would presumably be shifting toward greater innate predisposition toward religion as time passes. I do believe religiosity is heritable to some extent. More precisely I think there are particular psychological traits which make supernatural claims more plausible for some than others, and, those traits themselves are partially determined by biology. But obviously even if we think that religious inclination is partially heritable in a biological sense, it is also heritable in the familial sense of values passed from one generation to the next, and in a broader cultural context of norms imposed from on high. In other words, when it comes to these sorts of phenotypic analyses we shouldn’t get too carried away with clean genetic logics. In Shall the Religious Inherit the Earth? Eric Kaufmann notes that it is in the most secular nations that the fertility gap between the religious and irreligious is greatest, and therefore selection for religiosity would be strongest in nations such as Sweden, not Saudi Arabia. But as a practical matter biologically driven shifts in trait value in this case pales in comparison to the effect of strong cultural norms for religiosity.
Below are two of the topline tables which show the traits which are currently subject to natural selection. A + sign indicates that there is natural selection for higher values of the trait, and a – sign the inverse. An s indicates stabilizing selection, which tells you that median values have higher fitnesses than the extremes. The number of stars is proportional to statistical significance.
Some of this is not surprising. The age of the onset of menarche has been dropping in much of the world. I suspect this is mostly due to better nutrition, but a consequence of this shift is earlier fertility for some females. The authors are nervous about the robust correlation of higher fertility with lower intelligence, but notice that the pattern for wealth and income is different and more complicated. The key is to look at education. Whether you believe intelligence exists or not in any substantive concrete sense, those who are more intelligent are more likely to have had more education, and there’s a rather common sense reason why investing in more schooling would reduce your fertility: you simply forgo some of your peak reproductive years, especially if you’re female. The higher you go up the educational ladder the stronger the anti-natalist cultural and practical pressures become (the latter is a heavier burden for females because of their biological centrality in child-bearing, but both males and females are subject to the former). As with religion even if the differences have no biological implication because you believe the correlations are spurious or reject the existence of the trait one presumes that parents and subcultures pass on values to offspring. If higher education has anti-natalist correlations we shouldn’t be surprised if subsequent generations turn away from higher education. Their parents were the ones who were more likely to avoid it.
We live in interesting times.