Human parthenogenesis?

Buckaroo Banzai

Buckaroo Banzai

Mentat
Registered Senior Member
I've read in some places, briefly statements that is possible to a woman get pregnant of hersef, by her egg being fertilized by one of her polar corpuscles. This is true? Is it only possible, or have already happened? (can't be Jesus, from this sort of thing wouldn't result any male :p )
 
wow, that sounds pretty interesting. I once did some research on parthenogenesis for a science project, and I thought the process occurs consistently only in relatively simpler organisms such as aphids and possibly even ants.
(have you seen Jurassic Park, those female dinosaurs underwent parthenogenesis in order to reproduce :p haha but that's only fiction)
Well, "Life will find a way..." (From Jurassic Park):)
 
There's also at least a species of rock lizards, Lacerta unisexualis... I've found a paper about that somewhere in the internet once.
 
oh that's neat, let me be honest with you, for that science project, I was trying to test if parthenogenesis occurs in fruit flies (Drosophila Melanogaster) under certain conditions, and the results were negative. :(
 
I've heard about those lizards before in a biology class. They said that the offspring is essantionialy a clone of it's mother.
 
Ya hypothetically its possible, but I have never heard of a proven case of it happening in humans let alone mammals (well except for that one time were they made a mouse give birth to its own clone). By the way a women could only have a girl by parthenogenesis, it would not be a clone genetically because the genes have all be rearranged but it would likely look like a clone.
There are many biologist trying to develop theories that explain how it s impossible, kind of like how physicist making theories on how time travel should be impossible.
 
Altough that I certainly agree that it is very improbable, I'd not say confidently that's impossible... not after hearing about a thing that suposed happened with a woman in Italy, is said that she gave birth to his baby, and then they verified that she was still pregnant of twins... I do not know how it managed to occur... if really occurred. :bugeye:
 
Parthenogenesis can occur in human females. If a certain series of hormones is triggered, evan in the abstance of sperm an egg can still start developing. It is only hapliod, but it develops into a tumor that has hair and teeth. Freaky!
 
I just came across this thread. Parthenogenesis is not all that uncommon reptiles, for
instance, there have been several snakes in zoos which produced young without a
male being anywhere around, ala Jurassic Park. I thought I remembered reading
something fairly recently about a large mammal (can't remember what) that gave birth
through parthenogenesis in a zoo, but I can't find a link, so I may be mistaken. I do
have a link to the birth of bamboo sharks by parthenogenisis in a zoo. It was supposed
to have happened with some other sharks in another zoo, also.
http://news.nationalgeographic.com/news/2002/09/0925_020925_virginshark.html
 
Last edited:
Resurrecting one of my creations.....

I think that what I first suggested as parthenogenesis wasn't really this, since it involves fertilization of an egg by a corpuscle, and not an unfertilized egg developing spontaneously. I don't know how it would be called though... anyway, recently I found this dubious site with somethings on "virgin birth":
http://ourworld.compuserve.com/homepages/dp5/sex2.htm

In this page is said that the parovarium (organ of Rosenmüller) can produce sperm-like cells (they say "sperm"! not sperm-like...) that can fertilize her eggs. Anyone knows if that's true?


About true parthenogenesis in humans this site says
There is some evidence, however, that natural parthenogenesis does occasionally occur in humans. There are many instances in which impregnation has allegedly taken place in women without there being any possibility of the semen entering the female genital passage [2]. In some cases it was found either in the course of pregnancy or at the time of childbirth that the female passages were obstructed. In 1956 the medical journal Lancet published a report concerning 19 alleged cases of virgin birth among women in England, who were studied by members of the British Medical Association. The six-month study convinced the investigators that human parthenogenesis was physiologically possible and had actually occurred in some of the women studied [3].

refs.

2. Raymond Bernard, The Mysteries of Human Reproduction, Mokelumne Hill, CA: Health Research, n.d., pp. 47-50, 56-63.
3. Ibid., pp. 3-10.
Click to expand...

I don't know what "ibid" means, I guess that means that refers to the previous source of reference, but different pages....

Researching through google I found that parthenogenesis really occurs in humans, but in anywhere but in this site I found that a parthenote embryo can develop completely as a fertylized embryo, rather parthenotes result in teratomas, what was cited few posts ago by Enigma'07. I've found that teratomas can have several specialized tissues and organs, such as glands and even eyes, but in a messed manner. Although there's a phenomena called fetus in fetu, which some people think that may be a highly organized teratoma, I think I've read something about a functional heart.

This thing led me to think in a analogy for development, and I would like to know if this is valid, from someone expertised in this issues. Development would be like pulling, causing to fall a domino, triggering the fall of lots of dominoes organized in lines. Normal embryonic development, on fertilized eggs, would be like pulling the correct first domino piece; teratomas would be like pulling a domino on the middle of the way, causing to only a few of the pieces fall correcly, as planned.
If this analogy is valid, seems that a tremendous luck could result in a fully-correct developed parthenote (excluding non-letal effects of monosmomy... if such thing really could happen)... or there's something more fundamental in the development of mammals that crucially needs fertlization (by a male, necessarily, or female self-fertilization would fit?)?
 
I think someone above mentioned this: the imprinting pattern has to be correct for viable offspring to result.

That is, patterns of DNA methylation are different in male and female gametes. If a polar body were to fertilize an ovum (which sounds next to impossible, since it doesn't have the swimming and targeting machinery the sperm uses to find and fuse with the egg), the resulting embryo would have a double pattern of 'mom gene' methylation and no 'dad gene' methylation. I doubt it would be viable.
 
Can there be any possibilty of somewhat "self cloning"--a women get her own DNA to egg(if blank egg can be possible in natural way)? We sometimes see offspring matching exactly to either mother or father. If it can happen then women can only get a female baby.??
 
Update from the fan of the odd and the weird.
Look what I've found:

In 1995, for instance, Bonthron described another boy who was partially parthenogenetic: cells from his blood and certain other tissues contained none of his father's chromosomes; instead, they featured a duplicated set of one half of his mother's6. Although it is not unknown for an egg to start developing without being fertilized, fully parthenogenetic human embryos cannot develop to term. Bonthron, now at the University of Leeds, UK, believes that the partially parthenogenetic boy owed his unusual genetic constitution to an egg that spontaneously divided into two cells, one of which was fertilized. The second cell then copied its maternal chromosomes, allowing the resulting chimaera to form a viable embryo.
Click to expand...
http://www.unc.edu/courses/2002fall/biol/122/001/Human%20genetics%20Dual%20identities_files/DynaPage(1).htm


Kumar,
I'm not sure about the self cloning part, I guess that as in the gametogenesis allways gets only half of the genotype, so an hipothetical parthenote could never be a clone of the mother.
But in any instance that parthenogenesis occur, it only results in females, or at least in species in which females are determined by a pair of X chromossomes, or something like it.
 
Immaculate Conception?

George was dumbfounded.

He had been examining the shark, Tidbit, to figure out why she reacted badly to routine sedatives during a physical and died, hours after biting an aquarium curator on the shin. Now there was a bigger mystery: How did Tidbit get pregnant?

"We must have had hanky panky" in the shark tank, he thought.

But sharks only breed with sharks of the same species, and there were no male blacktip reef sharks at the Virginia Aquarium & Marine Science Center in Virginia Beach.

Could Tidbit have defied nature, resulting in the first known shark hybrid?

A recent study had documented the first confirmed case of asexual reproduction, or parthenogenesis, among sharks: a pup born at a Nebraska zoo came from an egg that developed in a female shark without sperm from a male.

One of the scientists who worked on that study contacted the aquarium, which sent him tissue samples from Tidbit and her pup for testing. If the pup's DNA turns out to contain no contribution from a male shark, this would be the second known case of shark parthenogenesis.
Click to expand...

http://www.boston.com/news/science/articles/2007/06/25/shark_bite_leads_to_reproduction_mystery/

Asexual reproduction in sharks?:confused:
 
I think mammals are just about the only major group of living beings that do not do this, ever.

Might have something to do with the internal womb and placenta.
 
Back to this eerie subject again. Adding some stuff I think wasn't mentioned before:

Mature ovarian cystic teratoma with a highly differentiated homunculus: A case report

[...]In this report, we document a case in which the solid portion of an ovarian teratoma demonstrated considerable differentiation, forming a doll-like structure.

A 25-year-old virginal Japanese woman underwent surgery for an ovarian tumor that was diagnosed as a mature teratoma. A solid mass within the tumor was found to have a head, trunk, and extremities. Consequently, this mass was diagnosed as a mature fetiform teratoma (homunculus). Brain, eye, spinal nerve, ear, teeth, thyroid gland, bone, bone marrow, gut, trachea, blood vessels, and phallic cavernous tissue were confirmed microscopically. Distinctive features were the clear anterior-posterior, ventral-dorsal, and left-right axes, with a spatially well-organized arrangement of the organs. An eye was located on the front of the head, a spinal nerve lay dorsal to the spinal bones, the thyroid gland was anterior to the trachea, and the gut was deep inside the trunk.

[...]

http://doi.wiley.com/10.1002/bdra.10133
Click to expand...


[...] It has been proposed that fetiform teratoma and fetus in fetu can be differentiated based on zygosity.4,9,16 As previously mentioned, most ovarian teratomas are homozygous at loci where the host normal tissue demonstrates heterozygosity, but fetus in fetu is genetically identical to its host. Cytogenetic examination was not performed on this case.

Clinically, ovarian fetiform teratomas and fetus in fetu present differently. Most reported cases of the latter have been discovered in infancy as an abdominal mass, and no case has been reported within an ovary.14,15 The most common location is retroperitoneal, although cases have been reported in the skull, sacrum, mouth, and scrotum as well.14,15 In contrast, fetiform teratomas are most commonly found in women of reproductive age and discovered as ovarian masses.3

Fetiform teratomas must also be distinguished from ectopic pregnancies. All reported cases of fetiform teratoma are composed of mature tissue and present without placental or trophoblastic tissue.4 However, there have been 2 reported cases of umbilical cord structures described in fetiform teratomas, in which histologic evaluation was not performed.4 A clinical history of an elevated β-human chorionic gonadotropin level and the documentation of chorionic tissue can substantiate the diagnosis of an ectopic pregnancy. [...]

http://arpa.allenpress.com/arpaonli...=10.1043/1543-2165(2006)130[1552:FTH]2.0.CO;2
Click to expand...


The last one states that homunculi have never been found with skeletal muscle, but another article reports such a case:

The limb buds and rudimentary digits consisted of rudimentary cartilage surrounded by fat, neurovascular bundles, and minute amounts of skeletal muscle with overlying skin (Figure 4, a).

http://findarticles.com/p/articles/mi_qa3725/is_200610/ai_n17196260/pg_2
Click to expand...





I'm almost sure I've read once about instances where a normal non-parthenogenic zygote develops into a "normal" teratoma-like mess of unorganized tissues and organs. Anyone knows how it's called?
 
Buckaroo Banzai said:
I've read in some places, briefly statements that is possible to a woman get pregnant of hersef, by her egg being fertilized by one of her polar corpuscles. This is true? Is it only possible, or have already happened? (can't be Jesus, from this sort of thing wouldn't result any male :p )
Click to expand...

this introduces fallacies in DNA replication...and the likelyhood that an offspring will be a mutant or have problems is quite high.
 
What is a "fallacy" in DNA replication?

The zygote wouldn't be exactly a mutant, but would have increased risk of problems related with homozigosity, and as with true parthenotes, probably problems of low-viability due to lack of a complementary male pattern of DNA methylation.


By the way, about the methylation subject, I've read in another forum someone suggesting that maybe a XXY woman could have this "solved". But I don't remember anything about this syndrome, I thougth that usually an abnormal number of sex chromosomes would result in sterility.

And I also think that maybe, somehow, the gametogenesis may just keep with the individual woman's "normal" methylation pattern, as if it was just a regular somatic cell in this regard.
 
You must log in or register to reply here.
Back
Top