All Female Species Found

Discussion in 'Biology & Genetics' started by Orleander, Apr 19, 2009.

  1. Roman Banned Banned

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    So the theory goes.
     
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  3. ElectricFetus Sanity going, going, gone Valued Senior Member

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    This is a theory that very well proven.
     
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  5. Captain Kremmen All aboard, me Hearties! Valued Senior Member

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    Does that mean that what makes humans male rather than female was the introduction of a separate species genes.
    Or does it mean that only male DNA carries the genes of the adopted organism.
     
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  7. Enmos Valued Senior Member

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    No, it means that only (the genetic material of) the mitochondria from the mothers side are passed on to the offspring.
     
    Last edited: Apr 23, 2009
  8. Roman Banned Banned

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    You mean there is an abundance of evidence for it.

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    Sex determination varies from species to species. Sometimes it's based on different chromosomes (XY or XX for human males and females, respectively, or ZZ and ZW for avian males and females respectively), the ploidy of the organism (non-fertilized eggs in the hymenoptera- bees, wasps, ants- with only half the complement of chromosomes), or environmental conditions (temperature differences at the nest site of some reptiles determines the sex of the eggs, some fish can change gender based on the gender proportions of the immediate population).

    However, the female in any species is defined by who produces eggs, and egg production is defined by the gamete that is big and has mitochondria in it. The reason why mitochondria aren't inherited patrilineally is mitochondria from the sperm, in almost all animals, is targeted for destruction by the egg after fertilization. Plants sometimes have patrilineal mitochondria, and it's speculated that it occurs very rarely in humans.
     
  9. ElectricFetus Sanity going, going, gone Valued Senior Member

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    There is an abundance of evidence for evolution too.
     
  10. Roman Banned Banned

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    And gravity.
     
  11. ElectricFetus Sanity going, going, gone Valued Senior Member

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    Exactly, now which do you see people more likely to say "there is much evidence for the existence of gravity" or "gravity is a proven force of nature"?
     
  12. Captain Kremmen All aboard, me Hearties! Valued Senior Member

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    Thanks . Nice answer.
    Any idea why the egg attacks the male mitochondria?
     
  13. Roman Banned Banned

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    Nope. I know it gets tagged with ubiquitin, which is a protein that gets put on anything the cell wants to degrade, but outside of that, I don't know. Wikipedia might.
     
  14. Roman Banned Banned

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    Recently? The former.
     
  15. ElectricFetus Sanity going, going, gone Valued Senior Member

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    your insane, we are talking lay people not esoteric cosmologist!

    I thought the sperm mitochondria which are all attached to the tail simple don't make it in?
     
  16. Captain Kremmen All aboard, me Hearties! Valued Senior Member

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    From Wiki:

    In most multicellular organisms, mtDNA is inherited from the mother (maternally inherited). Mechanisms for this include simple dilution (an egg contains 100,000 to 1,000,000 mtDNA molecules, whereas a sperm contains only 100 to 1000), degradation of sperm mtDNA in the fertilized egg, and, at least in a few organisms, failure of sperm mtDNA to enter the egg. Whatever the mechanism, this single parent (uniparental) pattern of mtDNA inheritance is found in most animals, most plants and in fungi as well. mtDNA is particularly susceptible to reactive oxygen species generated by the respiratory chain due to its close proximity. Though mtDNA is packaged by proteins and harbors significant DNA repair capacity, these protective functions are less robust than those operating on nuclear DNA and therefore thought to contribute to enhanced susceptibility of mtDNA to oxidative damage.
     

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