You know what else has unique human DNA like a fertilized egg?


Just sayin’.

Science aside of the day:
Well, and T lymphocytes. “T cells” are a type of white blood cell involved in the immune response. They’re special because they undergo something called somatic recombination.

Try to remember back to high school biology. During meiosis (the formation of gametes) there’s a step where Chromosome 1 from Mom and Chromosome 1 from dad can swap chunks of DNA – that’s recombination. It’s the reason why we have so much diversity – because you’re not just getting Grandma or Grandpa’s chromosome, you’re getting a mix of both.

Usually this only happens when making sperm or eggs, but there’s one time it occurs in non-gamete (somatic) cells – in the production of T cells. A protein called a T cell receptor recognizes antigens (foreign particles) from viruses, bacteria, parasites, and even tumor cells. But think of it – if there was just one gene coding for a T cell receptor, we’d only be able to recognize one type of antigen. That’s no good – we need to be able to recognize millions!

Thankfully evolution has the answer. The T cell receptor gene has three main segments: Variable, Diverse, and Joining. There are 65 V, 27 D, and 6 J – but the cell only needs one of each! That’s where somatic recombination comes in – it randomly deletes all but on of each segment, leaving the cell with a unique combination.

“But wait,” cry my more mathematical readers, “that only leaves 10,530 combinations! That’s not very diverse at all!” You’re right! These huge structural differences make up most of the diversity, but these genes are also hypermutable – they gain mutations WAY faster than other genes. So that contributes to the diversity even more!

So, are we ready to start calling every T cell a person because it has a unique human genome? I’m not sure if my psyche can stand all the funeral’s I’d be having every time I get sick.


  1. joslineK says

    Hey, Jen, I have a question…Growing up, I’ve always been anti-abortion, but more recently I have been trying to be a little more open minded :) According to my biological understanding and my Reproductive Biology professor, there is a high statistical probability that a conceptus will not become a fully functional viable human being before a certain point in the development of the potential fetus… My question is, does it make a difference? If there is a higher statistical probability that a conceptus will become human than that it will not, should abortion still be an understandable option after that point? Just Curious…

  2. says

    I don’t consider the probability of something making it to birth as reasoning behind why I’m pro-choice – but I do think it goes against some anti-abortion arguments (that every fertilized egg is going to be a human, for example).Why I’m pro-choice is more complicated than I can explain in a brief blog comment. The point of this post is that the “UNIQUE GENOME!!!” argument is faulty.

  3. PNW_Greg says

    Love the science lesson!One question — did you mean “Usually this only happens when making sperm or eggs”? I am not a biologist — and college was a long time ago for me, but I always thought this was the process that happened only when sperm and eggs, you know, *made out with each other*. I’m intrigued by the whole T cell structure hypermutable thing — I didn’t realize that our immune system had a built-in purposeful mutating mechanism. Fascinating.

  4. says

    Why aren’t they throwing their money into research programs that would “save” the little buggers for future implantation into good Christian wimmin ™? That would be a twofer for them – prevent “killing” and add to the population of indoctrinated glassy-eyed fundamentalists!Like the “snowflake” children.kind of getting back to topic… good to know. They don’t usually respond when I ask why isn’t it considered suicide or genocide or abortion when you clip a hangnail? There’s unique-ish DNA there too.

  5. says

    Sure, and skin cells grown in a petri dish has human DNA. But its’ not an organism and neither is cancer. Clearly you intentionally misinterpret this argument which is a cynical way of debating, not buying it yourself but hoping that others will.

  6. WhatPaleBlueDot says

    In my opinion, the probability of the conceptus becoming a live human is much, much less important than the bodily autonomy of the already living human woman it is attempting to inhabit. Pregnancy is dangerous. In my opinion it is a relationship deserving enthusiastic consent. And, more importantly, what matters most is NOT my crazy, uninformed opinions in the medical issues facing a competent adult and her physician. And, frankly, the increased risk pregnancy and childbearing hold for minors increases the importance of EVERYTHING EXCEPT OUR OPINIONS, and the weight of the consent and autonomy concerns.

  7. marcadler says

    Bringing teenage angst to issues that require mature perspectives.Thank you, internet.

  8. joslineK says

    Of course the health and “enthusiasm” of the woman should be considered, especially in the case of minors, those with mental or physical health problems, etc…. I just think that, if the numbers favor the fetus in terms of viability vs. non-viability (of the fetus), its well being should be considered too. I 0nly recently left religion, but most of the abortion arguments in the non-theist community seem to be just as “preaching to the choir” as the theist arguments are… theists seem to place higher value on new life, while athiests seem to more highly value older life… Just wondering if there is a middle-ground between the more logical points made by those in both views… hopefully one based on factual, scientific evidence.

  9. says

    Ok. Cancer is an uncontrolled growth of cells within an organism. According to Wikipedia an organism is “any contiguous living system (such as animal, plant, fungus, or micro-organism) /…/ In at least some form, all organisms are capable of response to stimuli, reproduction, growth and development, and maintenance of homoeostasis as a stable whole. “What cancer can do all of that? (Growth is not reproduction.)

  10. Orko says

    Here’s the thing: Until a certain point, said fetus is not viable outside the womb. Before that point, it has the same basic potential as a gamete. Sure, it may have forming parts, but it is lacking the ability to exist as an independent unit. Some people might not accept this but I do not accept the alternative. Before a fetus reaches viability, the only thing that makes it a “person” is the desire of the parent(s). After that point of viability, I can’t really make an argument for abortion..02

  11. Rollingforest says

    This is what is referred to as “begging the question”. Basically you are saying “I’m right because I say I am.” You have yet to explain what the fundamental difference is between the unique DNA of a skin cells grown in a petri dish and the unique DNA of a fertilized egg. You just seem to be arguing that anything that seems like a person to you is a person. But that’s not a good scientific argument at all because it has no logic to back it up. I think it is pretty clear that a fertilized egg can develop into a person but definitely isn’t a person right after conception. What characteristics do you use to define a person and why should those characteristics be taken as important? You can’t just reject Jen’s argument without giving a concrete reason.

  12. Rollingforest says

    What about bacteria that swap DNA with each other all the time? How can you divide them into separate species if there is no line separating between one species and the next?The whole idea of a species requires sexual reproduction, which a huge number of species do not do. So we humans don’t define cancer as a species simply because it doesn’t fit our preconceptions, not because there is anything fundamentally different about it.

  13. Rollingforest says

    Respond to the actual argument, Marc. Don’t (falsely as it turns out) accuse her of being a teenager and thus dumb.

  14. Rollingforest says

    Cancer cells can make copies of themselves. That is reproduction. There are many organisms that reproduce in non-sexual means.

  15. Palebluevoice says

    I was in a similar boat to you; new atheist and pro-life. My reasoning behind becoming pro-choice is as follows. Before a few weeks into the second trimester, a fetus cannot feel pain at all. It cannot feel emotions at any point in the second trimester; certainly not in the first trimester. In this regard, it has no more right to life than a sperm cell. It has human DNA and the potential to become an adult, but if it was an adult on life support, we would have no problem “pulling the plug”. As I said earlier, it begins to have the capability to feel pain after the second trimester. Normally, it would be immoral to kill a fetus; in the same way its immoral to kill an animal; but there are circumstances in which it is okay to kill animals, and even then, an animal living doesn’t do the same thing to a woman as a fetus. Moreover, over 90% of abortions are first trimester. When it is second trimester, its a more difficult procedure for everyone; its not used for birth control as pro-lifers would have you believe, but for health problems, or someone being irresponsible and not finding out about it(Who would most likely be either a young teenager or unfit parent). Now, for third trimester. Nobody is going to carry a fetus past the second trimester and then change their mind. Third trimesters are serious fucking medical procedures. Again, not done as birth control. Nobody is going to change their mind this late; if they could afford it a couple months ago, they can afford it now(if someone got laid off, they’ll find another job and/or use savings). The doctor will get reported if he tries to convince a healthy woman to have a third trimester abortion, and damn fast(pregnant women are knowledgeable about these things), so its not going to be done for money, as the prolifers would have you believe. I say nobody; its extremely unlikely, since natural hormones have people wanting to care for their fetus, but its certainly possible. It doesn’t, in my opinion, outweigh the other side. Abortion should be completely deregulated.

  16. the_Siliconopolitan says

    And how many foetuses reproduce?The Pope doesn’t reproduce – does that mean he’s not an organism?Oh … “capable”. But is the Pope capable of reproduction? Would God allow him to be elected, if he were truly about to have kids?

  17. the_Siliconopolitan says

    What the hell is angsty about somatic recombination? I wasn’t the most precocious of teenagers, so I may be wrong, but those are not two words I associate much with teenagedom.In fact, the only immaturity I see here is your (and my) style of argumentation.

  18. TerranRich says

    So are you in favor of protecting cancer as a form of life? REALLY think about your answer, Rollingforest…

  19. says

    I didn’t realize the Pope was a species in and of himself. An elderly woman (most likely) can’t reproduce. So she wouldn’t be human, then?When we talk about a species being able to reproduce, we don’t mean picking one of two members of that species at random and seeing if they can, or want to, reproduce.

  20. says

    Cancer cells aren’t organisms in themselves because they formed from another life form’s cells and mutated out of control. That’s not a species in itself.

  21. says

    Really? The difference is that one is a living organism, a member of Homo Sapiens, the other is skin cells – no organism, no Homo Sapien. I don’t think I can put it simpler than that.A person is a somewhat different concept than a human being. Personality, though highly heritable evolves with time so in that sense I’m not sure that concept applies here. What I say is that human beings regardless of what stage in development they are, do not compare with skin cells or tumors in the sense that taking an undeveloped human life is the same as getting rid of a tumour – which is essentially what she is saying.

  22. says

    I don’t divide them into species, biologists do that. And I’ve never heard a biologist refer to cancer as an organism. You can use you own personal definition of organism if you like, but I try to stick to the biological definitions. There are several but like I said, none which as far as I can tell include cancer.

  23. marcadler says

    Nobody said you have to be a teenager to have teenage angst. I never said she was dumb. She obviously isn’t, which makes this response all the more disappointing.I responded to the argument in the thread to the previous post.

  24. Rollingforest says

    Perhaps I wasn’t clear earlier. No I’m not in favor of protecting cancer cells. I’m not in favor of protecting fertilized eggs either. Neither is the same as a baby. Look, I understand that pro-lifers truly feel that aborting a fertilized egg is murder and that PETA members truly feel that eating a hamburger is murder, but I don’t think that either of them are right. They’ve taken a good principle (protecting people) and taken it to the extreme so that it doesn’t resemble what it started out with.

  25. says

    So much fail here. Just because you’ve never heard of it doesn’t mean it doesn’t happen! Look up CTVT or DFTD for examples of cancers that have crossed over into ‘organism’ territory.You write as if you are familiar with the biology behind species concepts and speciation, but clearly you’re not. If you were, you’d know that most species concepts don’t apply to single-celled, asexual entities like tumor cells, bacteria, viruses, etc. Many species concepts for these organisms would indeed classify some tumor cells as a separate species. You make broad claims like “…I try to stick to the biological definitions. There are several but like I said, none which as far as I can tell include cancer.” Please make sure you are actually familiar with the biology before you put words in the mouths of evolutionary biologists like Jen and myself. But all of this is irrelevant. Even if no cancer was ever classified as a ‘separate organism’ from its host, your original argument still makes no sense. “What I say is that human beings regardless of what stage in development they are, do not compare with skin cells or tumors in the sense that taking an undeveloped human life is the same as getting rid of a tumour…”This is yet another perfect example of begging the question. ‘Developing human beings are different than skin cells because I say so. Therefore I am right.’ Why, exactly, is a fertilized egg different than a single human cell? And don’t give me the tired ‘potential for development’ argument that’s complete lunacy when it comes to the actual science.

  26. Rollingforest says

    It is true that comparing a fertilized egg to a tumor is not a good political move, but their is some truth to it. To start off, no I am not saying that a fertilized egg is something to be feared the same way you would fear a tumor. A fertilized egg is not deadly most of the time like a tumor is. But a tumor isn’t a Homo Sapien. A fertilized egg could potentially grow into a member of Homo Sapiens, but it isn’t yet. Early in the pregnancy it’s just a cell and should be treated as such. In certain situations a skin cell could be turned into another human using artificial methods. So declaring that a fertilized egg is an organism while a skin cell isn’t doesn’t take the reality of biology into consideration. Being born “naturally” doesn’t make you any more of a human than someone who is a clone, for example. I personally think it the issue of personhood does matter. If you don’t have the concept of personhood then the facts of biology make it too hard to pin down exactly how moral you should be toward this or that particular combination of cells. There is no characteristic, except consciousness, which differentiates the people you have moral requirements toward and the biological cells that you don’t.

  27. Zephirum says

    That settles it then — Every cancer is unique and precious!Chemotherapy is depriving the lives of cancer cells.

  28. Rollingforest says

    My personal understanding is that it is consciousness that separates personhood from nonpersonhood. Both humans and rocks are made of the same material (protons, neutrons, and electrons). The important difference for humans is that they are conscious and can feel pleasure and pain. That is why moral value is connected to them. Consciousness in humans in connected to the brain. Without a brain, you can not be said to be truly alive even if your blood is still pumping. The brain develops during the second trimester. Therefore, it seems to me that personhood begins then too. In my view, before the second trimester there is no person so there is no reason to forbid abortion. During or after the second trimester, the baby’s right to not be killed takes the most consideration. That seems to me to be the logical distinction.

  29. Zephirum says

    There were discussions about whether HeLa cells can be described as a new species “Helacyton gartleri”, because it satisfies most if not all definition of an organism.Other examples include infectious cancers that can skip from hosts to hosts.Biology isn’t as well defined as the way you like it to be.

  30. Chris Lawson says

    Also worth pointing out: identical twins share an identical genome. By the “unique human DNA” argument, the twins only count as human life *as a pair*, so you could kill one of them and still have the unique genome of the other to use as a defence in your murder trial.

  31. Jackhuskey says

    Ok, I am pretty sure you know this allready but I am going to play along with you. The diffrence between a cancer cell and a zygote is that if you keep them both in ideal growth mediums without any further artifical manipulation one of them will turn into a person and the other won’t. Assuming you can clone a person from skin cells doesn’t make skin cells people. After you do the incredible act of science and make the skin cells into cloned zygotes, yes now they will grow into people with no further artifical manipulation ergo people. A sperm cell and an egg cell are not people, mix them… people. You and I and everyone has to draw the line about where “people” start, and we will draw it diffrently. Then the abortion law will ignore the millions of diffrent opinions and draw one line that is now the law from sea to shining sea. GRR.

  32. Craig says

    Something to consider:Even if aborting a fetus was equivalent to the killing of an independent human being (which, let us be clear: it isn’t…but, for the sake of this argument, assume for a moment that it is), then the ending of that “life” (square quotes used to highlight the point that the definition of “life” is a complicated issue in this context) is, at worst, justifiable self-defence.Imagine for a moment that another person forced you, against your will, to submit to treatment that was:a) Excruciatingly painful for a period of hours or days.b) Intensely uncomfortable and physically crippling for a period of months (back pain, incontinence, haemorrhoids, limited mobility, etc.).c) Very likely to lead to some degree of permanent physical scarring and disability (despite what the celebrity magazines imply, your body is highly unlikely to return to its pre-pregnancy state afterwards: ).d) Had a significant chance of causing death.There isn’t a court in the land that wouldn’t allow a self-defence plea to any charges arising from killing the person who was going to do that to you. Whether or not they consciously intended to cause those outcomes is irrelevant: self-defence does not require malice on the part of the attacker, only that the defender has a reasonable expectation of harm to themselves.This is pregnancy; carrying a child to term is not an inconvenience, it’s a life-threatening condition that is inevitably accompanied by temporary disability and frequently accompanied by permanent harm. No one should be forced to submit to it against their will.

  33. A-M says

    I don’t find this argument would convince an anti-abortionist to change their mind, for the simple reason that if you took some cancer cells and you took a zygote and placed them in environments that would allow them to thrive, one would become a deadly tumour, and one would become a living person. If you specifically wish to prove that zygotes are not the only unique DNA substance in humans, fair enough, but I don’t think most anti-abortionists base their opinions solely on that. I would never have an abortion on an otherwise healthy foetus and my reasoning is based entirely on its potential, not on whether it is unique. Having said that, I would never deny another woman the right to choose what to do with her own body. I suspect the problem is not the actual views of anti-abortionists, more that some anti-abortionists feel the need to impose their views on others. I’d be angry enough if you told me I couldn’t dye my hair a certain colour, let alone if you dictated whether or not I had to carry a pregnancy to term. Thus why, despite my own views on the matter, I’m not going to critisize another woman for her own views on the matter, even if she disagrees with me. I can’t pretend to know what is right for everyone, on account of not being an omniscient being. That would be pretty hypocritical for an atheist.

  34. says

    That does make you look even worse, of course.One could almost think that you are an agent from the other side, really a born-again, conservative country-music fan running a blog to lampoon the sensible people in society by exaggerating their views to an extreme caricature.

  35. WhatPaleBlueDot says

    You missed the more important word in that sentence. It wasn’t enthusiasm, but consent.

  36. Svlad Cjelli says

    Mathy mutant students, isn’t it likely that the majority of all human cells are “unique”? Or are at least more than half of the cells in an average, adult human body still identical?

  37. Svlad Cjelli says

    And there’s actually something interesting to note here!The Tasmanian Devil as a species is afflicted by a kind of cancer that may be commonly contagious.It would migrate like a parasite or bacterium (It does have a metabolism, so not as much virus-like.), and should no longer depend on the genetic material of the hosts. The original host is long dead.

  38. Arctic Ape says

    Obviously, the probability of further survival doesn’t matter, if you think that the zygote is *already* a person.If you value the “personhood potential” of the zygote, you could argue that the low probability of survival takes away much of your responsibility of killing it, a bit like if you’re stealing a lottery ticket that has a small chance of winning. However, many people might not accept this kind of logic if they refuse to compare the values of actual and potential persons.In my experience, people generally can’t explain why potential matters anyway, they just use it as an excuse when they feel that zygotes should be equated with later stages of human development. (The “unique DNA” is the favorite excuse for those who openly equate zygotes and adults.) The importance of potential simply feels less plausible when you know that most zygotes never develop into adults. On the other hand, knowledge of the actual properties of embryos and understanding of gradual development might weaken the need for such excuses in the first place.

  39. Rollingforest says

    But unfertilized eggs, if you add the extremely abundant resource of sperm, can produce potential babies. Why is a fertilized egg worth the same as a baby, but an unfertilized egg, which can easily be fertilized, suddenly worthless? That seems like such a huge leap in value for such a small change that can be simply corrected. Would you tell your kids “I loved you enough to protect the fertilized egg that became you with my life, but I didn’t care about you enough to provide the sperm to your unfertilized egg to give you life. That happened entirely by accident.” In truth, the only difference between an unfertilized egg and a fertilized one physically is that there is a little bit of extra DNA. But to me the big difference between a person and a nonperson is consciousness. We are responsible for protecting people who can feel pain from harm. A fertilized egg can not feel pain. It doesn’t have hopes or dreams. It doesn’t have a personality. All it is is a cell that has a little extra DNA that kick starts growth. We need to focus on whether a particular fetus IS a baby, by whether it has consciousness, not whether it has the potential to be a baby, which unfertilized eggs can have too if you add a little sperm, which is easily available.

  40. says

    So is cancer an organism or not? “Crossed over into “organism” territory” is not that convincing. Nor does “asexual entitiy”. True I’m not a biologist but searching the web I can’t find any biologist who claims cancer is an organism. Are you about to update Wikipedia on this anytime soon? It doesn’t mention cancer at all. “But all of this is irrelevant. Even if no cancer was ever classified as a ‘separate organism’ from its host, your original argument still makes no sense.”If that is true, why didn’t your comment begin right there? “This yet another perfect example of begging the question. ‘Developing human beings are different than skin cells because I say so. Therefore I am right.’ Why, exactly, is a fertilized egg different than a single human cell? And don’t give me the tired ‘potential for development’ argument that’s complete lunacy when it comes to the actual science.”No, not because I say so but because one is a human being and the other is not. I care more about human beings than skin cells. Again I quote Wikipedia which usually is correct:”Human fertilization is the union of a human egg and sperm, usually occurring in the ampulla of the uterine tube. The result of this union is the production of a new individual of the human species (homo sapiens), complete with a unique set of the 23 pairs of chromosomes that genetically specify a human organism, the sperm and the egg each providing 23, for a total of 46 chromosomes.”It is this new member of Homo Sapiens that I want to protect.

  41. Palebluevoice says

    The brain develops, yes, but not the consciousness; the brain hasn’t fully developed yet. If you’re opposed to killing things with brains no matter the circumstances, I should certainly hope you are a vegetarian, and don’t eat fish either. Even farther, whats the difference between a fish and a bacteria? The fish has a brain which controls its basic instincts, but doesn’t a bacteria have instincts, just using a different mechanism? Would we kill a person with artificial legs because they have no legs? Of course not! LYSOL IS MURDER! Sorry for the sarcasm at the end, but I simply couldn’t help it.

  42. joslineK says

    Thanks for all the help, everyone! You’ve given me quite a bit to think about…

  43. says

    Pardon me, but did you just try to dismiss the knowledge of people who are relative experts in the field of biology (Jen’s a grad student and Adam, I assume is at least similar..) by quoting an online encyclopedia, the content of which can and is regularly edited by anyone at any time????Seriously, Jen or Adam or any of us could go into Wikipedia and edit that entry you quote to say:”Human fertilization is the union of a human egg and sperm, usually occurring in the ampulla of the uterine tube. The result of this union is the production of a zygote with a unique set of the 23 pairs of chromosomes, of which the sperm and the egg each provide 23, for a total of 46 chromosomes. This embryo, if it correctly attaches to the uterine wall–which it doesn’t always do–and it doesn’t miscarry–which happens about 25% of the time–will usually grow into a fetus, which then eventually will be born as a juvenile of the species Homo Sapiens.”That would totally undermine the claim–I wouldn’t call it an argument–that you are presenting here and there wouldn’t be anything for you to do than to go into wikipedia and change it back to whatever you want it to be.It is for exactly these reasons that my students–and I teach engineers how to write–are NOT allowed to use wikipedia as a reliable and credible source. The info there is too open to modification and doesn’t undergo a strict peer review process before it is used.

  44. Numad says

    Some of those are even on Wikipedia!…This Paradigm person certainly did thorough Wikipedic research. Of course, this doesn’t contain the word “organism,” which I hear is now the absolute, objective criterion for this issue until someone finds a precise counterexample; in which case the absolute, objective criterion will become something else.

  45. says

    There is a comedic you-tube video waiting to happen here with someone playing up the cancer angle–but only at the end.. I mean–it would start out:”We all know that new life, with a unique genetic code, is created within human beings. This life grows all on its own, taking shape and being nourished in this body.Some people, however, want to kill this new life–to cut it out and poison it! These monsters don’t recognized the beauty of this new, unique life!Please join us and supporitng a law to prevent chemotherapy and invasive cancer removal! WE must save the tumors!”

  46. says

    There is a lot of appeal to authority here. I thought that was what priests did.Editing the article by changing “individual of the human species” to “embryo” does not accomplish very much. The embryo is still a human life, a Homo Sapiens. It doesn’t become that once you call it a fetus or after birth. You have to edit that article way more to undermine my argument. And if that doesn’t help you can always go back to the authority argument again.

  47. says

    Do you mean genetically unique? I’d expect the chance of every cell in my body being genetically unique is pretty low; sure, some are going to have slight mutations in their genome, but every single one, and a different mutation every single time?

  48. says

    Paradigm,1. I did not appeal to authority in the way that priests often do. I appealed to expertise. Appeals to authority when they involve expertise are not the same thing as a general appeal to authority. Expertise–which is what I clearly implied with the fact that Jen and Adam have studied the field of biology a lot more than you have–by your own admittance–means that they are likely to know a lot more about the biology of the situation than you do. This is no different than trusting a surgeon to know how to cut out your appendix than some random person on the street who has googled it. If you are not willing to concede that expertise actually may have some bearing on the biological facts here, then you are not serious. As an addendum… If you are talking about priests and authority–one might actually find that if you are talking about catholic theology–that priests are a legitimate authority to appeal to–as they have more training there than the average person. Disputing their knowledge of catholic theology by looking to wikipedia would be just as false as doing what you are doing here. It’s when a priest (or you) start trying to argue that wikipedia entries have as much expert knowledge as people who’ve done a lot more indepth study of the subject and then try to claim that such entries ARE EQUALLY AUTHORITATIVE on the subject, that you see who’s really pulling an “appeal to authority”–namely–it is you who are doing so.2. You keep making a claim without providing evidence. Repeating that an embryo is a human life does not make it true. Because you don’t seem to get this–I’ll just adopt your tactic.I disagree with you. An embryo or fertilized egg is not human. Thus, you are wrong. Haha.If you don’t find this convincing–I ask you to ponder how your claim that a fertilized egg is a human is any more valid or convincing than what I just said. So far–all you’ve done is state this and occasionally then try to provide supporting evidence–but then that evidence keeps getting eliminated or found wrong or wanting–and then you keep coming back to an unsupported claim. Figure out a way to provide better evidence or go home.

  49. says

    Since I for some reason cannot reply above (only like) I will answer tricstmr here:Appealing to expertise without using it is in my view appealing to authority. It is saying “I’m right because I have a higher education”. “You keep making a claim without providing evidence. Repeating that an embryo is a human life does not make it true. Because you don’t seem to get this–I’ll just adopt your tactic.I disagree with you. An embryo or fertilized egg is not human. Thus, you are wrong. Haha.”You do this already, you never explain in what way the embryo is not human and in what way it is not alive. You just say it will grow into a Homo Sapines:”This embryo, if it correctly attaches to the uterine wall–which it doesn’t always do–and it doesn’t miscarry–which happens about 25% of the time–will usually grow into a fetus, which then eventually will be born as a juvenile of the species Homo Sapiens.”So when is it a human life? Does life begin when the embryo becomes a fetus, when it is born or when it is fully developed at ca 18 years of age? These seem very arbitrary points in development to say – “there, it’s alive!”

  50. Svlad Cjelli says

    Yep, genetically unique is what I meant.But every single one would be overkill, and so would the mutation being different every time.I phrased it very poorly above, but the main question was about how many of the gene sets are identical, and if the largest identical group are a majority or a minority.The point being to continue the trendy premiss here and ask if a human body would be one human individual or many more. :P

  51. says


    These huge structural differences make up most of the diversity, but these genes are also hypermutable – they gain mutations WAY faster than other genes. So that contributes to the diversity even more

    This is not quite right, especially for T-cells. The process of recombination is error prone, and where the V, D and J segments are linked up, random nucleotides can be deleted or added. You could say that the B-cell receptor gene is more prone to mutation, but that’s because there’s an enzyme (AID) targets this specific locus during a specific stage of development (germinal center expansion) – it doesn’t just accumulate mutations naturally. Finally, the combinatorial math is not quite right. Because the TCR has an alpha (only V and J segments there) as well as the beta chain you describe. So there’s a few more things to multiply in that equation.And now I feel like a dick for so much nit-picking, but I have to pretend my immunology PhD is worth something.

  52. says

    My nephew just sent me this post, and said I should look at it, I am glad I did. However, I would have to slightly not agree as some of this literature is debateable, however, it remains a wonderful read.

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