Gene Expression

i-c5cd7cefc02e0ceff4494f8c8f16f046-leroi.jpgA few years ago the developmental geneticist Armand Leroi burst on to the scene with the engaging book, Mutants, and a controversial op-ed where he attempted to rehabilitate the concept of race. Leroi’s op-ed spawned a rebuttal website which brought together a variety of scholars from disparate disciplines to refute his arguments.

Never one to shy away from controversy Armand has published a new essay, The future of neo-eugenics, where he lays out what is happening, and will possibly happen, from the perspective of an evolutionary biologist. The great thing about Armand’s work is that he cranks out the numbers. I found that some of my earlier assumptions in regards to eugenics were fallacious. So, here are the numbers….

  • Each year 4 million babies are born within the United States. The expectation of Down Syndrome based upon the rate of chromosomal mutation would be 6,150 babies. Leroi estimates that only 4,370 babies with this condition are born each year, extrapolating from an abortion rate of 29% of fetuses diagnosed with Down Syndrome in Atlanta, GA, and Hawaii (the only places where there are data).
  • In Western Australia 32% of the fetuses with Down Syndrome were aborted, in South Australia 75%, in Taiwan 80% and in Paris 85%.
  • Please remember though that Down Syndrome males are sterile, and females far less fertile than the median, so the eugenical effect of this is only epiphenomenal.
  • Leroi also points out that increased frequency of conception by older mothers has balanced out the eugenical impact of abortions so that the number of individuals with this condition has been constant (i.e., the abortions cut into a larger number of potential Down Syndrome children).
  • “40% of infants with any one of 11 main congenital disorders were aborted in Europe.”
  • “… in 2002, 20% of fetuses with apparent birth defects were aborted in G8 countries–that is, between 30,000 and 40,000 fetuses.”
  • “In Western Australia, neonatal mortality rates due to congenital deformities declined from 4.36 to 2.75 per 1,000 births in the period from 1980 to 1998. Half of that decline is thought to be due to the increase in abortions of abnormal fetuses….”
  • In Taiwan, screens for thalassaemia mutations have caused the live-birth prevalence of this disease to drop from 5.6 to 1.21 per 100,000 births over eight years
  • “…comparative genomic hybridization (CGH) microarrays could be used to screen a single embryo or fetus for thousands of mutations.”
  • Based on the number of known mutations Armand calculates that it should be possible to predict disease to a reasonable confidence in 1 in 252 embryos.

A major caution about massive genetic preimplantation screens is that they would be preimplantation. That is, some sort of IVF would be needed. It seems implausible that this would be widespread, but Leroi points out that IVF procedures already make up several percent of the pregnancies in Western nations. The cost of a typical IVF procedure is that of a medium sized car, and crucially, the cost of many diseases over one’s lifetime is far greater (IVF would be like “insurance”). Lero concludes thus:

Some readers might find it peculiar that in this discussion of neoeugenics, I have not considered the ethical or legal implications with which this subject is generally considered to be fraught. Although I do not doubt their importance, I simply have no particular knowledge of them.

One might find this sort of conclusion glib, but before one can make ethical judgements one must understand of what one speaks, and that is the crucial role of public intellectuals like Leroi. As I’ve noted, concepts like genetic load, mutational load and the importance of reproductive variance in selection are common concepts which evolutionary biologists are aware of, and over beers many an objective scientist will mull over the implications of higher fertility of lower socioeconomic orders, the problems that might occcur because of the survival and reproduction of those whose fitness is instrinsically burdened with illness palliated by medical intervention and the long term evolutionary arc of our species. Armand’s piece points out several important issues. First, the new eugenics is already here. Second, the new eugenics will become more powerful as information gathering via genomics becomes more omniscient, and medical interventions in fertility become more omnipotent. Third, there is variance in the extent that different individuals and groups are willing to avail themselves of the opportunities offered by the new eugenics. A acquaintance of mine who has been involved in research in France offered that higher socioeconomic status parents were much more likely to abort than lower socioeconomic parents when the fetus exhibited abnormalities. Germany tends to frown upon eugenical technology (for obvious reasons), but most East Asian nations have few compunctions about utilizing these tools in family planning. For evolution to occur via natural selection all you need is differential reproduction tracking traits which exhibit heritable variation, the new eugenics will do nothing but accelerate and modulate this trend.

A new story in The New York Times, Wanting Babies Like Themselves, Some Parents Choose Genetic Defects, illustrates these issues on a less abstract level. You have here parents who want “children like them.” Deaf lesbians who seek out a sperm donor who is deaf so that their child can be deaf, and consciously deny their son technology which could palliate his lack of hearing. The reason? Because he would not be fully part of the deaf community. Additionally a difference between parent and child like the ability to hear would introduce a chasm. The other primary group highlighted are individuals with darwfism. One mother-to-be states:

Mary Ellen Little, a New Jersey nurse with dwarfism, had her first daughter before a prenatal test for achondroplasia was available. For her second child, she had amniocentesis. “I prayed for a little one,” meaning a dwarf, she told me.

The wait, she recalled, was grueling, since “I figured I couldn’t be blessed twice, but I was.” Both her daughters, now 11 and 7, are “little people.

Is this ethical? I don’t know, that’s up to your values. Some people might say that it is hard to grow up in the world as a dwarf, and that dwarf parents are doing wrong in seeking to create children who perpetuate this abnormal condition. But people could also say the same for being born of a minority racial type. Should non-whites simply not reproduce so they do not perpetuate suffering in the next generation? This is a philosophical position taken by some religious groups in the past as an argument for celibacy, so it isn’t a novel idea. There is the concern by the dwarf parents that a “normal” height child won’t relate, that the difference would induce a strain. The deaf parents who seek a deaf child often give the same rationale, that they want children who are like them. And yet what about parents who are of different races, should they not have children because the child won’t look like either of them, and would be “out of place” no matter where they were? Perhaps ugly people shouldn’t reproduce, we know how the ugly are teased. And so on.

These questions don’t have easy answers if you are a mere mortal. For myself, I am much more concerned about children born deaf than children born dwarves. The latter are in a difficult position, but they are not invisible and they can communicate easily with the rest of our species. In contrast, deaf children are boxed in by the nature of their lack of a hearing facility. What if blind parents wanted to genetically engineer a blind child who they could relate to? What are children, are they ends toward parental satisfaction and fulfillment? Or are children something that we as a community all have a stake in? An important consideration is that health care is partly a public good, and if society is expected to pay for particular medical bills one might assume that society should have a say in which children come into the world. Ultimately I think the choices should be individual, but when they become ubiquitous I think we will need to demarcate Good and Evil, optional and mandatory. We’re just starting….

Update: Download Leroi paper .

Comments

  1. #1 Julia
    December 6, 2006

    You remark that

    many an objective scientist will mull over the implications of higher fertility of lower socioeconomic orders

    What would you say are some of those implications?

  2. #2 King Aardvark
    December 6, 2006

    I saw Armand’s Mutants show, and it was excellent. I wish someone would rebroadcast it.

    For the implications of higher fertility in lower economic orders, are you refering to the simple economic strain on a government with a higher and ever increasing percentage of poorly educated citizens, or are you talking about some physical evolutionary implications?

  3. #3 Matt
    December 6, 2006

    Can you post a free link to that paper?

  4. #4 Cynthia
    December 6, 2006

    I’m curious, did the woman with dwarfism have amniocentesis to see if her fetus had dwarfism? If it hadn’t, would she have aborted the non-dwarf fetus? Or was she testing for other genetic abnormalities? Apologies if this was in the NY Times essay, I couldn’t find a free version.

  5. #5 Fly
    December 6, 2006

    In the coming decades stem cell treatments will become common. In some cases donor cells will be used that are genetically distinct from the patient. As the technology matures, the donor cells will be genetically modified for enhanced effectiveness. Artificial chromosomes may be added. The typical human may become a chimera, composed of cells with different genetic lineages. Some cell types may be optimized for muscles and others for nerves. Original genetic material will determine less of who we are.

    In the longer term, it will be possible to rebuild tissues. Neural pathways will be laid out, plasticity restored, and senses trained. Such technology will derive from procedures used to repair and rehabilitate brain damage. This should eventually lead to cures for those who are born deaf or blind.

    The technology to remake humans should make eugenics less important.

  6. #6 Rikurzhen
    December 6, 2006

    Fly: The technology to remake humans should make eugenics less important.

    It’ll come down to timing. I could make an educated guess as to which technologies will work out first/best, but it wouldn’t be worth much.

  7. #7 Reale
    December 6, 2006

    Eugenics is good per definition. Evolution directed righteously. Otherwise it’s dysgenics.

    For obvious reasons, I think that if we had had some more eugenics in the past, there would’ve been fewer enemies of it today.

  8. #8 sparc
    December 6, 2006

    Please remember though that Down Syndrome individuals are sterile, so the eugenical effect of this is only epiphenomenal.

    To my best knowledge this only accounts for male Down patients while female Down patients can reproduce.

  9. #9 chet snicker
    December 6, 2006

    What would you say are some of those implications?

    the proportion of superbrights is shrinking.

    are you refering to the simple economic strain on a government with a higher and ever increasing percentage of poorly educated citizens, or are you talking about some physical evolutionary implications?

    more the latter.

    Can you post a free link to that paper?

    did it.

    If it hadn’t, would she have aborted the non-dwarf fetus? Or was she testing for other genetic abnormalities? Apologies if this was in the NY Times essay, I couldn’t find a free version.

    she wouldn’t have aborted, though she wasn’t clear.

    To my best knowledge this only accounts for male Down patients while female Down patients can reproduce.

    yes, thanks. i fixed it. there is one case in the literature of a male with down syndrome fathering a child. females are sub-fertile, that is, lower than the norm.

  10. #10 joeo
    December 6, 2006

    The risks of major genetic defects don’t seem to be so great to make IVF worth it for most people. Such tests will probably become increasingly popular for those already doing IVF.

  11. #11 Fly
    December 7, 2006

    “the proportion of superbrights is shrinking.”

    Increased assortative mating over the last few decades should have significantly increased the proportion of superbrights.

    Better nutrition and less disease should significantly increase the average IQ in nations such as China and India. (E.g., less iodine deficiency in China.)

    The diets of pregnant women are improving (e.g., vitamin and omega 3 oil supplements) and baby food formulas are improving.

    Fewer environmental contaminants such as lead.

    Advanced communications has enriched the intellectual environment for people. Connected by the Internet, intelligent people can interact more often. I suspect this culturally enriched environment produces more superbrights. (In the past a superbright Chinese peasant had little opportunity for intellectual growth.)

    Until recently there has been 3 point average increase per decade in measured IQ. (Flynn Effect)

    I believe that dysgenics is decreasing the frequency of good “g” genes. (Based on female fertility rates compared to education level.) If the trend continued for many generations it would be worrisome. However, there are offsetting nutritional and cultural factors. I think that competition for the top slots at elite universities has significantly increased and that may indicate that the proportion of superbrights is increasing.

  12. #12 The Superfluous Man
    December 7, 2006

    I must be missing something very basic (besides the limited geography), but Leroi reports a 30% abort rate for those diagnosed with down syndrome, while this paper ( http://www3.interscience.wiley.com/cgi-bin/abstract/65500197/ABSTRACT?CRETRY=1&SRETRY=0 ) reports about a 90% rate.

  13. #13 Fly
    December 7, 2006

    “30% abort rate”

    Perhaps many Downs babies are born without screening? Of the parents who do test for Downs, perhaps 90% choose to abort their Downs fetus and those aborted fetuses represent 30% of potential Downs babies?

  14. #14 Agnostic
    December 7, 2006

    Increased assortative mating over the last few decades should have significantly increased the proportion of superbrights

    Only if brightness/dullness were fitness-neutral: same frequencies of alleles, just shuffled in a sorted way, increasing variance in both directions. But brightness has had a fitness cost over the time-period when assortative mating significantly increased.

  15. #15 The Superfluous Man
    December 7, 2006

    Fly, I thought that at first but checked, and both statistics are of those prenatally diagnosed with down syndrome. From the ‘Atlanta’ study cited: “One hospital-based study in the United States reported that following prenatal diagnosis, established before 24 weeks of gestation, most couples (86%) chose to terminate their pregnancies with Down syndrome-affected fetuses (Caruso et al., 1998). Data for 1993-2000 from other monitoring programs show thatamong all cases with Down syndrome born to mothers of 35> years the proportion that were electively terminatedwas 50-100% in Europe, and 33% in Canada (ICBDMS, 2002). An Australian study showed an increase in the proportion of electively terminated cases with Down syndrome from 31% to 75% from 1990 through 1996 indicating the impact of increased use of prenatal testing (Cheffins et al., 2000).”

    Perhaps the diagnoses were carried out at different stages of pregnancy, with the higher rate at an earlier stage. The Atlanta study didn’t cite the one with a ~90% figure.

  16. #16 Stephen
    December 11, 2006

    I have no trouble selecting for dwarfism, per se. However, isn’t dwarfism linked with a short life span? That’s probably a zero cost feature, but may not be considered fair to the child.

    On the other hand, in a thousand years, those selecting for long life spans may have had fewer generations than these dwarfs, and so could be less “evolved”. Take a look at animal breeding programs. Much can happen in just a few generations.

    Perhaps with genetic manipulation, one could get a longer lived, healthy short child.

    What would i want? Surely, someone like me, but without a high likelyhood of heart disease or alzheimer’s. It’s hard to pick a partner who can give you exactly those things, that you can stand to be with.

    Humans no longer have to compete with scary preditors or diseases. With low pressure, we’re at a dead end. Genetics could really get the ball rolling again.

  17. #17 AG
    December 18, 2006

    Humans no longer have to compete with scary preditors or diseases. With low pressure, we’re at a dead end

    Wrong, for human, our real competion is from other fellow human being. Human die and killed more by other human than any other specieces. Just like olympiad game, we are more interested in competion against our closest kins.

  18. #18 Lab Lemming
    December 18, 2006

    With respect to East Asia and possible applications of eugenics, you might want to consider that the current amount of selection against trisomy 21 is much less prevenant than that against disomy X. Even without genetic testing, and even with laws in place that forbid the practice, the use of ultrasounds to cull disomy X victims (aka females) is by far the most obvious eugenic result to come out of China and India so far. The social effects of this selection will probably dwarf the effects of selection based on other genetic criteria over the next few decades.

  19. #19 Aidan
    March 7, 2008

    Dwarfism and a shorter life are a commom misconception. Dwarfs have the same life expectency as normal people. Plus, not all dwarves have dwarves and some average sized people have children with Dwarfism. Eugenics is all about making the “perfect” human being. But in reality can you do that? I mean look at the flu for example. Every year it evolves and bypasses the vaccines for the previous year. Who’s not to say that by trying to create the “perfect” human that even more deadly diseases evolve and are much harder to cure or treat. A virus is an organism that feeds or thrives in a host. If you believe in evolution then wouldnt they evolve to their surroundings. Just putting this out there.

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