micro-chimerism

biology is so cool:

“Our Selves, Other Cells”

“[F]or any woman that has ever been pregnant, some of her baby’s cells may circulate in her bloodstream for as long as she lives. Those cells often take residence in her lungs, spinal cord, skin, thyroid gland, liver, intestine, cervix, gallbladder, spleen, lymph nodes, and blood vessels. And, yes, the baby’s cells can also live a lifetime in her heart and mind.

“Here’s what happens.

“During pregnancy, cells sneak across the placenta in both directions. The fetus’s cells enter his mother, and the mother’s cells enter the fetus. A baby’s cells are detectable in his mother’s bloodstream as early as four weeks after conception, and a mother’s cells are detectable in her fetus by week 13. In the first trimester, one out of every fifty thousand cells in her body are from her baby-to-be (this is how some noninvasive prenatal tests check for genetic disorders). In the second and third trimesters, the count is up to one out of every thousand maternal cells. At the end of the pregnancy, up to 6 percent of the DNA in a pregnant woman’s blood plasma comes from the fetus. After birth, the mother’s fetal cell count plummets, but some stick around for the long haul. Those lingerers create their own lineages. Imagine colonies in the motherland….

“How many people have left their DNA in us? Any baby we’ve ever conceived, even ones we’ve miscarried unknowingly. Sons leave their Y chromosome genes in their mothers. The fetal cells from each pregnancy, flowing in a mother’s bloodstream, can be passed on to her successive kids. If we have an older sibling, that older sibling’s cells may be in us. The baby in a large family may harbor the genes of many brothers and sisters. My mother’s cells are in my body, and so are my daughter’s cells, and half my daughter’s DNA comes from her dad. Some of those cells may be in my brain….”

whoa.

wikipedia says (so it must be true): “After giving birth, about 50-75 % of women carry fetal immune cell lines. Maternal immune cells are also found in the offspring yielding in maternal→fetal microchimerism, though this phenomenon is about half as frequent as the former”

(note: comments do not require an email. chimera!)

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18 Comments

  1. @r j p – “My answer to that though, would be, ‘I don’t know, how big of a whore are you?'”

    heh.

    i think you may have missed the bit about all the different kids leaving their dna behind in ma — so if ma has 8 kids (ouch!), then ma might get bits of all of their dna, plus kid number 8 would get ma’s dna (and dad’s) plus, maybe, some dna of siblings 1-7.

    your question is still a valid one, tho. (~_^)

    Reply

  2. I got the part about the number of kids, one sis has 6, and another has 5.

    My mom keep’s asking me “when am I going to have any?”
    Last time, I told her “hbd chick told me I need to become a swinger to meet women.”

    Reply

  3. How many of these cells actually generate tissue? There are rare cases in which major organs in a single individual have different genomes, presumably from different sources. Or so I have read.

    Reply

  4. Here’s a reference:

    “The second type is called tetragametic chimerism. This occurs when two separate ova are fertilized by two sperm and produce two zygotes. When these zygotes fuse, it forms an organism that has two distinct cell lines, and the resulting fetus may be male, female or hermaphroditic. It usually occurs with fraternal (or dizygotic) twins, and often forms from zygotes produced from artificial in vitro insemination. As a result, the individual may have “populations” of cells: one set of DNA may appear in his or her liver and another set may appear in his or her lung.”

    I have a fraternal twin brother. Maybe some of me is him?

    Reply

  5. @luke – “I have a fraternal twin brother. Maybe some of me is him?”

    the tetragametic chimerism thing doesn’t apply to you and your brother ’cause in that sort of chimerism, one of the zygotes is actually absorbed by the other, so at the end there’s only one individual with two sets of dna. since you and your brother actually exist, that obviously didn’t happen. (^_^)

    however, according to this guy, 8% of fraternal twins are blood chimeras ’cause they shared the same blood supply when they were in the womb, so there is a possibility that you and your brother are chimeras on that level. (don’t anybody miss the picture on page 24 of that pdf. that is too cute/funny!)

    cool! (^_^)

    i would think also that there are good chances that you swapped some other cells here and there and microchimerism prolly applies to you two as well, but that’s just a guess on my part.

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  6. Thanks for the clarification. I do have an auto-immune disorder however. My thyroid went out 25 years ago. Never thought of blaming my brother.

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  7. @luke – “Never thought of blaming my brother.”

    everything’s always your brother’s fault. i thought all brothers everywhere knew that. (~_^)

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  8. @jayman – “Imagine poor Michelle Duggar and 19 of her soon to be 20 kids…”

    didn’t you hear? number 20 went straight to heaven. (why do i devote brain cells to these things?)

    i used to know this woman who was one of eighteen children. she was the youngest and when she was 50 years old, her oldest sibling (a sister) was 80. the thought of having eighteen children just always blew my mind. i mean, there were probably a couple of other pregnancies in there, too, you know? miscarriages. sheesh. none of the kids were bums, though!

    Reply

  9. @hbd chick,

    No I didn’t hear, I totally don’t follow the Duggars… ;) When you consider that some people are so prolific while others aren’t (in the “Brainwash” episode on sex, it is mentioned that a quarter of Norwegian males have no offspring), how can question that evolution continues right up to the present day.

    Reply

  10. @jayman – “When you consider that some people are so prolific while others aren’t … how can question that evolution continues right up to the present day.”

    exactly! i mean, that’s exactly what natural selection is! some individuals leaving more descendants behind than others, right?

    bob sykes has pointed out a couple of times (thnx, bob!) that a lot of people who “believe” in evolution (i hate that turn of phrase) don’t actually understand the concept of natural selection. i never realized this before bob mentioned it. i think he’s right — and it’s a big problem. i mean, ’cause they don’t get the fundamentals of it, they can easily say stupid things like “human evolution stopped 50,000 years ago” or whatever. *facepalm*

    Reply

  11. A role for microchimerism in obesity and evolution? (2/10/2012)

    “Our hypothesis is that metabolic regulation adjusts the risk of predation to environmental conditions in that low food supply disconnects predation risk from genomic variability, thus preventing additional harm. However, increased genomic variability may cause weight gain, elevate predation risk and, in modern times, lead to metabolic diseases. Over time, this process of “immunological incompatibility” may separate subpopulations with altered genomic loci within a population by driving overlapping clusters into extinction. Alternatively, when isolation of a subpopulation in a niche is not possible this may even eliminate one or more subpopulations, such as probably happened between Homo sapiens and Homo neanderthalensis. Such an interbreeding between human subspecies might have resulted in obesity, despite a more restricted food supply than currently available. This may be illustrated by the overweight statue of the Venus figurines such as the Venus of Hohle Fels although their obese nature is usually considered as a symbolic artefact. These Venus figurines originate from the Late Stone Age (starting about 40,000 years ago) which matches the period of the Neanderthal extinction.”

    http://www.pdf-archive.com/2012/02/22/a-role-for-microchimerism-in-obesity-and-evolution/

    Reply

  12. Since this topic is alive again… ;P

    “bob sykes has pointed out a couple of times (thnx, bob!) that a lot of people who “believe” in evolution (i hate that turn of phrase) don’t actually understand the concept of natural selection. i never realized this before bob mentioned it. i think he’s right — and it’s a big problem.”

    I was thinking about this recently, and I think that people who claim to believe in evolution, but not understand the particulars, not only fail to understand natural selection, but don’t grasp the concept of heredity—or don’t realize how heritable psychological traits are. I would blame the myth of nurture; people believe eye color is heritable but not that IQ, religiosity, or political leaning is heritable. That disconnect is the fundamental problem preventing people from understanding HBD, because once one grasps evolution by natural selection and the heritability of mental traits, that heritable factors are in part responsible for human differences inevitably follows.

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  13. @jayman – “…because once one grasps evolution by natural selection and the heritability of mental traits, that heritable factors are in part responsible for human differences inevitably follows.”

    i think it’s even simpler than that: all one needs to do is understand evolution by natural selection — everything else follows from that!

    if you get that — really get it — then you’ll get that different populations of humans must differ in all sorts of ways ’cause of our different evolutionary histories. end of story. it’s really not rocket science. (if it were, i wouldn’t get it! (~_^) )

    (and isn’t the fact of human biodiversity just cool?! (^_^) )

    Reply

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