Cybrids and Hybrids

Embryo research into stem cells which may be used to treat serious diseases is very much in the news. As the Human Fertilisation and Embryology Bill will shortly have its next reading in the House of Commons, we need to decide where we stand. The issues are complex, and the opinions expressed contradictory. Let me try to shed a little light.

Stem cells, which are found both in embryos and in adults, are unspecialised but have the capacity to self replicate and develop into specialised cells. Consequently they have many uses in the development of the embryo and the regeneration of tissue.

Is it morally permissible to mix human and animal genetic material in order to produce sufficient embryonic stem cells for research which may lead to important therapies? I focus on two ways of doing this envisaged in the Bill. In one technique a human nucleus is placed in an animal egg. It is claimed that 99.9% of the organism is human.

This risks the creation of a human embryo with a non-human partial mother. The claim that only 0.01% would be animal is disingenuous because the issue is not the proportion but the actual effects which the animal element has on the organism. Scientists in the field must be aware that such arguments are misleading, yet their devotion to fact does not inhibit the propaganda.

It is argued that the benefits of obtaining sufficient embryonic stem cells for research provide such potential for the treatment of serious diseases that the creation of cybrids (as these are known) is justified. To which the unavoidable answer is that it would not matter how great the benefit if the procedure were wrong in itself.

Whether research into embryonic stem cells, which are in short supply and ethically questionable, will lead to important break-throughs is a matter of dispute. Many scientists take the view that work with adult stem cells is far more promising. Yet unlikely avenues have yielded surprising discoveries in the past. One can never rule out the possibility of future benefit. But no doubt useful information was gleaned from the experiments of Josef Mengele on concentration camp inmates, or from the grotesque sexual experiments conducted by Masters and Johnson. However, many useful therapies have now been developed using adult stem cells, and none from embryonic cells. But we cannot predict the future.

The other involves fertilising animal eggs with human sperm. This would produce some kind of hybrid – a mixture of man and animal with unknown results. The purpose of such a procedure is not clear, but new information, negative or positive, would emerge.

The Bill does not permit the results of either technique to remain alive after 14 days, and such work requires a licence. However the Authority has only ever turned down one licence application and refusal was reversed on appeal.

The reporting of public opinion on these questions is an object lesson in itself. One recent poll showed substantial opposition, another showed substantial support. The difference shows the importance of the phrasing of the question. The first simply asked about allowing scientists to create embryos which are part-human and part-animal. The second spoke in terms of embryos which were mostly human, that they could lead to the understanding of serious disease, and that these embryos would be destroyed and not implanted in a womb. The different phrasing of the question evoked the different responses.

In looking at the moral issues involved I will assume that the normal human embryo is a human being merely at an early stage in its development. An issue to be discussed on another occasion.

The ethics depend on your value system. Our society has decided that, up to 14 days gestation, the conceptus has no intrinsic value and consequently requires no particular respect. Indeed the developing baby enjoys very limited respect until it sees the light of day. At which point its interests suddenly become paramount. The apportionment of respect is inconsistent and arbitrary but it concludes that what we do with embryos is a practical rather than a moral question.

The Catholic belief is that the act of generation is the biological means through which man, made in the image and likeness of God, comes into existence and begins its journey towards its eternal destiny. Consequently every action which is taken must fully respect both the process of generation and the human life which is the result.

The two issues I have discussed are not identical. The implantation of the human nucleus in a largely evacuated animal egg seems to be the most serious since we are speaking of a possibly human embryo denatured by the effects of animal DNA.

Creating a hybrid through a fusion of animal and human gametes (eggs and sperm) strikes me instinctively as more repulsive. It is hard to think of a more gross way of abusing the process of generation and betraying human dignity.

I write of Catholic belief but not necessarily of the belief of Catholics. It is likely that some, at least, would disagree with me on at least the evacuated animal egg question. Indeed I have read articles and letters to that effect in the Catholic press. But what do you think? Perhaps you have some additional points to add that will contribute to our understanding. Let us hear your views.

From The Catholic Herald, 9 May 2008


About Quentin

Science Editor, Catholic Herald. Portrait © Jacqueline Alma
This entry was posted in Bio-ethics, Catholic Herald columns. Bookmark the permalink.

18 Responses to Cybrids and Hybrids

  1. hugo1963 says:

    I think Quentin has got in just in time with this article. I see that the second reading of this bill comes up on 12 May. But of course there are other issues, and some may be more important.
    There is the question of female couples being assisted to conceive babies, and also the matter of lowering the age for abortion.
    All pretty important too, I think.

  2. Irene says:

    Hugo is right, but he’s behind the game. The old HFE act (1990)
    allow human sperm to be injeted into hamster eggs for sperm-testing purposes. The test is no longer used.
    And just recently some people in Newcastle have been putting human embryonic stem cells into cows’ eggs. And all done under licence I believe.

  3. Frank says:

    It is a fundamental Catholic principle that we cannot do evil that good may come. To treat human cells as no different from animal ones for experimental purposes, is an evil.

    Is it therefore permissable to transplant e.g. a pig’s organ into a human being to help keep that person alive? I believe I read somewhere that transgenic (if that is the right word) transplants have successfully taken place.

  4. Blue says:

    Frank says “To treat human cells as no different from animal ones for experimental purposes, is an evil.” He needs to explain this statement a little more before I could accept it as it stands.

    I do see a difference between fertilising an evacuated animal egg (as, as Quentin says, possibly producung an embryo), and using a spare animal part as he describes. But I am not sure if I could put that difference into words. Can anyone help here?

  5. Frank says:

    I mean that persons are intrinsically different from animals (having souls) and therefore we should treat them with reverence, either at the very start of life, when apparently they look like a full-stop, and at the end of life when the body starts to wear out. What I have read of these biotechnological experiments suggests a ‘pick and mix’ attitude that is very irreverent.

    Using an animal organ to keep someone alive does not seem to detract from human dignity in the same way – perhaps because the intention is to preserve the life of a person, a laudable motive.

    I recall a Catholic medical student telling me she always prayed befor dissecting a corpse. Generally medical students are thought to be flippant about bodies; they get inured to the sight, as do scientists with their test-tubes of nascent life (which, of course, doesn’t even ‘look’ human). But reverence for the body is intrinsic to Christianity.

  6. Horace says:

    “reverence for the body is intrinsic to Christianity”
    I seem to remember that for a long time dissection of dead bodies was not permitted by the Church. This is, of course, no longer true.
    Perhaps our attitude to genetic manipulation will similarly change with time as we get to know what we are really doing.

  7. Aardvark says:

    Horace raises an interesting point. But surely there is a weakness with his analogy between dissection and embryonic stem-cell research. The former involves a deceased human body, while the latter involves the destruction of a living human embryo. The moral principles involved are therefore quite different.

  8. Mark says:

    I read Quentin’s article “Cybrids and Hybrids” with great interest, as a biochemist and an adult Catholic convert. There are a few technical points on which I would quibble slightly- no mixing of human and animal genetic material in fact is involved in the process proposed for creating these cybrid cells (which I have seen claimed in several Christian sources), but the animal cells are “enucleated” (that is, the animal DNA is removed) and the human DNA (from “somatic” or body cells) is inserted in its place (that is how they are described to be at least 99.9% human). In fact, DNA is transferred between species (including between animals and humans) through various viral means among others- this is par for the course in the way that organisms evolve. If the human DNA, say, comes from a mature skin cell, I’m sure that no-one would argue that these cells carry any great moral import, as thousands of them are sloughed off and destroyed every day after showering, for example. It begs the question, ‘how is an embryo defined?’. These cybrid cells revert to an embryonic state, rather than being embryos that are created through the process of fusion of an egg with a sperm cell. Nevertheless, the fact remains that they are ‘artificial’ laboratory creations that would never see the light of day through natural means; and the Archbishop of Canterbury, when asked in the Cardinal’s lecture series about the Anglican perspective on the HFE Act, was totally right to have reservations about the morality of creating these cells only that they may be destroyed after 14 days.

    On balance I would side with the Church’s opposition to this research. Sadly, non-believing scientists are never going to ‘buy into’ our argument that we are created in the image of God (which underpins, in my view, the whole of the theological opposition to this research), and that this procedure is an assault (or an insult?) on human dignity.

  9. Mark’s information here is a perfect instance of my request for additional information from experts. Our thanks to him. It leads me to raise a couple of points.
    First, is it relevant that only lowly skin cells, but with their complement of DNA, may be the ones used for cybrids? What matters is that a human/animal entity capable of development is the outcome. This is possibly an embryo.
    Second, the small amount of animal element involved is mitochondrial, of which Roger Highfield of the Telegraph writes: ”The 99.9 per cent figure probably refers to the fact that there are 37 instructions (genes) in mitochondrial DNA, compared with 29,000 in nuclear, which means 0.1 per cent animal instructions. But this is hardly reassuring.
    Decades of work has shown that even one genetic spelling mistake in the three billion letters of the nuclear code can be fatal – just 0.0000001 per cent.”
    Most of us are easily confused by the ways in which the experts talk about genes. For instance we hear that we share 99% of genes with chimpanzees, and so conclude that there is only 1% difference between the species. Without getting into the detail of the multi-functions of identical genes, this conclusion is simply false. But it makes a good, popular, headline.

  10. Just a small point. Horace says: “I seem to remember that for a long time dissection of dead bodies was not permitted by the Church. This is, of course, no longer true.” In fact it was never true, although it has often been repeated as fact. The details can be found in the Catholic Encyclopaedia at

    The article is headed “Anatomy”

  11. Horace says:

    Correction noted!

    However, for example, Ronald Bruce Meyer
    in an article on Andreas Vesalius (1514) says (inter alia) :-

    “In fact, human dissection was considered forbidden by the Roman Church since Tertullian and Augustine. Later, a bull (De Sepulturis, 1300) of Pope Boniface VIII . . . was construed as forbidding all dissection, with the added bonus of excommunication for those engaging in it.”

    “That the Pope never expressly forbade the dissection of cadavers is immaterial. That the bull was interpreted this way, and the Inquisition prosecuted for it, are material.”

    I know one must not believe everything one reads on the Internet (or anywhere else for that matter) – but this is more or less what I was taught as a medical student, in what was then a “Catholic University”.

  12. For Horace. I agree. The examples in history of discrepancies between the Church’s actual teaching and its everyday practice are numerous. I think immediately of slavery and the treatment of the Jews.

    But to get back to your original point, the earliest reference I can find, and you may know it, to reverence for the body, and to Natural Law, is Antigone (442 BC) where she says of King Creon’s refusal to bury the slain Polynices:
    “I did not think your edicts strong enough
    To overrule the unwritten unalterable laws
    Of God and heaven, you being only a man.
    They are not of yesterday, or to-day, but everlasting.
    Though where they came from, none of us can tell.”
    Trans. E F Watling. Penguin
    It is an irony that Sophocles understood the reverence due to the dead body of a human being, while many of our modern scientists don’t know it of a live one.
    I’m sure we’ll get round to genetic manipulation before long. Hope so.

  13. Mark says:

    Having recently read an interesting article in The Tablet by Neil Scolding entitled “Beware false promises” (17 May), I wish to make a further comment or two in the light of the legislation concerning the creation of human-animal embryos, which as we now know was successfully passed by Parliament yesterday. That article details how the media may have portrayed the therapeutic benefits that may ensue from the proposed research in an overly favourable and positive light. The reality is that the generation of stem cells from these cybrids up to the first 14 days of embryonic development would have very limited usefulness in terms of their clinical applicability; the great strides and advances that have arisen thus far have come predominantly from adult stem-cell research.

    The research that was granted the go-ahead in last night’s vote is purely exploratory; I don’t think that this message has not been conveyed very clearly by the media. Cures for debilitating diseases such as Parkinson’s and Alzheimer’s disease would be more likely to come from a strategy of re-programming mature adult cells so that they may become equivalent to embryonic stem cells, which could then be converted to cells and tissues for transplant. This would ensure that patients could effectively “grow back” their own tissue when in need from their own cells, and the need for the exploitation of any embryos in research would be negated. Admittedly, research along these lines is itself only in its very infancy, too; but would not pursuing this goal be better, especially since the most contentious ethical issues are laid to rest? In recent months, it has been shown by the research group of Shinya Yamanaka how genetically modified mouse skin cells can act like embryonic stem cells through re-programming (see “Nature Reports Stem Cells”, doi:10.1038/stemcells.2007.6)/

    In the light of this, perhaps we can lament a genuine lost opportunity in last night’s vote; if the financial resources that will now be pushed in this direction do end up in something of a scientific cul-de-sac or blind alley with no real possibility for the development of therapies useful to humans, as seems eminently possible, then the hopes of those suffering from debilitating diseases will have been raised unrealistically by the way in which this research has been represented in the media.

  14. tim says:

    The Bill is being sold on a false prospectus – with promises of fabulous cures obtainable in no other way. If the sponsors were trying to raise capital, they’d be open to prosecution. In the early nineties, it was made legal to experiment on human embryos. Similar claims were made. Where are the cures that were promised then?
    Of course, all knowledge is good in itself, but it can be tainted by the methods used to produce it (as with evidence obtained by torture).

  15. RM Blaber says:

    You make an elementary biological mistake, Mr de la Bedoyere, when you say ‘[t]he other [technique] involves fertilising animal eggs with human sperm.’
    The definition of ‘species’ entails that no members of one species may, in general, breed successfully with the members of another. The exceptions are few. A horse can breed with a donkey, but they belong to the same genus, and the offspring, both mules and hinnies, are always infertile.
    This does not apply to sub-species. A Western Lowland Gorilla (Gorilla gorilla gorilla) could mate successfully with a Cross River Gorilla (Gorilla gorilla diehli), but not with an Eastern Lowland Gorilla (Gorilla beringei graueri).
    Hybridisation actually involves genetic engineering, and the artificial insertion of human DNA sequences into animal genomes.

  16. R M Blaber makes a useful distinction between genus, species and subspecies, although I understand that biologists are not always agreed about the boundaries at species level. Revisions take place from time to time – and particularly since distinctions can be made nowadays via the study of DNA. There is no one simple test.
    On the question of fertilisation it is certainly tricky to thread one’s way through the clauses and subclauses of the HFE Bill, but, if I have my threads rightly connected, it refers to“an embryo created by replacing the nucleus of an animal egg…by one human gamete…” Now, I may have misunderstood this, but since this, at least in principle, produces an embryo, which can now develop further, it reads to me like fertilisation. I think I need some further explanation to tell me what I have misunderstood.

  17. RM Blaber says:

    The process described in the HFE Act is called enucleation and nuclear transfer. It entails the wholesale removal of (say) the nuclear DNA from a cow’s ovum and its replacement with a human genome. The cell walls, cytoplasm, cellular organelles and mitochondrial DNA are still those of the cow, but the nucleus now contains, not a human gamete (which is a haploid germ cell) but a complete diploid set of human chromosomes – all 23 pairs, the 22 autosomes, plus the 2 sex chromosomes. These will obviously have come from a human embryo, which will have been destroyed in the course of the experiment.
    Fertilisation of one species by the gamete of another is biologically impossible. A human could not mate successfully with a chimpanzee (either Pan troglodytes or Pan paniscus) for the simple reason that humans have 23 chromosome pairs and chimps have 24, even though 96% of their DNA is identical.
    To achieve unification of two different species’ nuclear DNA requires genetic engineering, using various techniques to snip lengths of DNA out of the animal genome and then insert human DNA in their place. I’m sorry to repeat the point, but there really is no other way of doing it. And of course, we Catholics would far rather it were not done at all!

  18. noshikafudo says:

    i dont understand anything

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