Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Why Isn't 'Mitochondrial Eve' 'Y-Chromosomal Adam's' Mom?

  1. Aug 7, 2009 #1
    Why Isn't 'Mitochondrial Eve' 'Y-Chromosomal Adam's' Mom??

    I hope the title explains my question.

    I understand that Y-Chromosomal Adam is the most-recent y-chromosomal common ancestor of every living human. I *think* I understand that there may be other recent common male ancestors, but they wouldn't have passed on their Y-chromosomes to every living human without an unbroken patrilineal chain (as required to pass a common y-chromosome?). I get that it has been shown that every human alive today has inherited mitochondrial DNA from Mitochondrial Eve. And I *sorta* get that means that Mitochondrial Eve must be the most-recent female common ancestor for the human population.

    So, how come we don't all have common mitochondrial DNA from Y-Chromosomal Adam's mother?
     
  2. jcsd
  3. Aug 7, 2009 #2

    mgb_phys

    User Avatar
    Science Advisor
    Homework Helper

    Re: Why Isn't 'Mitochondrial Eve' 'Y-Chromosomal Adam's' Mom??

    Men potentially have more offspring than women.
    Women rarely have more than a few surviving children, men can have pretty much unlimited.
    Imagine an inhabited desert island where Brad Pitt (or whoever is hunk of today) washes ashore, he could conceivably (sorry) be the father of all the next generations of kids, but they would all have different mothers.
    For a particular women to be the mother of everyone would require that all the other womens children die.
     
    Last edited: Aug 7, 2009
  4. Aug 7, 2009 #3

    D H

    User Avatar
    Staff Emeritus
    Science Advisor

    Re: Why Isn't 'Mitochondrial Eve' 'Y-Chromosomal Adam's' Mom??

    Why should we? For example, suppose Y-Chromosomal Adam's mother only had sons.
     
  5. Aug 7, 2009 #4
    Re: Why Isn't 'Mitochondrial Eve' 'Y-Chromosomal Adam's' Mom??

    BUT, they would all have the same grandmother. Therefore, they would all inherit the same mitochondrial DNA from Brad's mom (.....or am I missing something?)

    Maybe this is the part I'm missing. Doesn't mitochondrial DNA pass to all offspring, male or female?
     
  6. Aug 7, 2009 #5

    mgb_phys

    User Avatar
    Science Advisor
    Homework Helper

    Re: Why Isn't 'Mitochondrial Eve' 'Y-Chromosomal Adam's' Mom??

    No, only eggs have mitochondria - so they are passed on (edit "inherited") only through the female line.
    That's the whole point of the mitochondrial eve stuff.

    (actualy sperm do have a few but they are only little and aren't passed on)
     
    Last edited: Aug 7, 2009
  7. Aug 7, 2009 #6
    Re: Why Isn't 'Mitochondrial Eve' 'Y-Chromosomal Adam's' Mom??

    mgb_phys, mitochondrial DNA is passed from mothers to their offspring regardless of the offspring's sex. We all come from eggs and sperm .
     
  8. Aug 7, 2009 #7
    Re: Why Isn't 'Mitochondrial Eve' 'Y-Chromosomal Adam's' Mom??

    Men don't pass mitochondrial DNA.
     
  9. Aug 7, 2009 #8

    mgb_phys

    User Avatar
    Science Advisor
    Homework Helper

    Re: Why Isn't 'Mitochondrial Eve' 'Y-Chromosomal Adam's' Mom??

    But they are only further passed on through daughters - that is the important point the OP was missing.
    You get all you mDNA from your mother, your maternal grandmother and so on ...
     
  10. Aug 7, 2009 #9
    Re: Why Isn't 'Mitochondrial Eve' 'Y-Chromosomal Adam's' Mom??

    This was exactly the part I was missing :shy::blushing: Thanks.

    Went back to Wikipedia: Mitochondrial DNA comes from the egg portion of the zygote, so all mammals receive mDNA from the female line only. (Technically, would that be all sexually-reproducing species receive mDNA from the female line only?)

    OK, if I now understand this, I *think* this means that 'Mitochondrial Eve' is NOT the most-recent female common ancestor (because that could be Y-Chromosomal Adam's mom, or someone even more recent), but she is the most-recent matrilineal common ancestor. Is this correct?
     
    Last edited: Aug 7, 2009
  11. Aug 7, 2009 #10
    Re: Why Isn't 'Mitochondrial Eve' 'Y-Chromosomal Adam's' Mom??

    This would only be possible if Eve was Adam's sister. :eek:
     
  12. Aug 7, 2009 #11

    mgb_phys

    User Avatar
    Science Advisor
    Homework Helper

    Re: Why Isn't 'Mitochondrial Eve' 'Y-Chromosomal Adam's' Mom??

    Or his clone!
    Are rib-based stem cells allowed in the bible belt?
     
  13. Aug 7, 2009 #12

    mgb_phys

    User Avatar
    Science Advisor
    Homework Helper

    Re: Why Isn't 'Mitochondrial Eve' 'Y-Chromosomal Adam's' Mom??

    Yes, it's not impossible that there is some species (probably not a mamal) where the sperm has some mDNA that makes it into the egg but I don't know of any.

    Correct, ancestor is used slightly differently in genetics than in family trees.

    Also mitochondrial eve is much older than y-chromosone Adam because of the number of offspring. It takes many generations for chance early deaths and son-only families to end up with a single female ancestor, but it only takes a good looking or powerful chieftain with a roving eye to be Y-chromosone Adam.
     
  14. Aug 7, 2009 #13
    Re: Why Isn't 'Mitochondrial Eve' 'Y-Chromosomal Adam's' Mom??

    I just clicked on one of the 'related links' from the bottom of the page:

    "Mitochondrial DNA Recombines": https://www.physicsforums.com/showthread.php?t=25701

    It appears that enough paternal leakage of mDNA may occur to off-set the previous mDNA clock calculations by some TBD amount. It will be interesting to follow this as it develops!
     
  15. Aug 16, 2009 #14
    Re: Why Isn't 'Mitochondrial Eve' 'Y-Chromosomal Adam's' Mom??

    Indeed. There are some species of mussel where mtDNA can be transmitted through the paternal line. There is also a type of algae (genus Chlamydomonas) with two genders, + and -, where both gametes contribute chloroplasts (and chloroplast DNA) to the zygote, which is usually only inherited maternally. The chloroplasts then proceed to attack each other until the ones from the + gender inevitably win. The last special case that I know of is a slime mold with 13 genders arranged in a sort of hierarchy, where mtDNA is always inherited from the "higher" parent.
     
  16. Aug 16, 2009 #15

    Danger

    User Avatar
    Gold Member

    Re: Why Isn't 'Mitochondrial Eve' 'Y-Chromosomal Adam's' Mom??

    Lucky buggers! I can't even talk W into a 3-way...
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Why Isn't 'Mitochondrial Eve' 'Y-Chromosomal Adam's' Mom?
  1. Y-Chromosomal Adam (Replies: 5)

Loading...