parthenogenesis

lunamoth

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Parthenogenesis of human eggs is being reported as an alternative way to achieve stem cells without using fertilizes eggs. I will also post here any info I find about spontaneous parthenogenesis in humans.

parthenogenesis
Related: Biology

(pär&180;thenōjĕn´esĬs) [Gr.,=virgin birth], in biology, a form of reproduction in which the ovum develops into a new individual without fertilization. Natural parthenogenesis has been observed in many lower animals (it is characteristic of the rotifers), especially insects, e.g., the aphid . In many social insects, such as the honeybee and the ant, the unfertilized eggs give rise to the male drones and the fertilized eggs to the female workers and queens. The phenomenon of parthenogenesis was discovered in the 18th cent. by Charles Bonnet. In 1900, Jacques Loeb accomplished the first clear case of artificial parthenogenesis when he pricked unfertilized frog eggs with a needle and found that in some cases normal embryonic development ensued. Artificial parthenogenesis has since been achieved in almost all major groups of animals, although it usually results in incomplete and abnormal development. Numerous mechanical and chemical agents have been used to stimulate unfertilized eggs. In 1936, Gregory Pincus induced parthenogenesis in mammalian (rabbit) eggs by temperature change and chemical agents. No successful experiments with human parthenogenesis have been reported. The phenomenon is rarer among plants (where it is called parthenocarpy) than among animals. Unusual patterns of heredity can occur in parthenogenetic organisms. For example, offspring produced by some types are identical in all inherited respects to the mother.

from: http://www.encyclopedia.com/html/p1/partheno.asp

lunamoth
 
Here's one that is interesting, but needs verification:

4. Virginal reproduction
In cases of parthenogenesis (virgin birth), an ovum starts to divide by itself without fertilization, producing an embryo in which the paternal chromosomes may be replaced by a duplication of maternal ones. This asexual reproductive method is rare among warm-blooded vertebrates but more common among invertebrates. Pathological parthenogenesis has been observed in higher animals, such as the frog, fowl, and certain mammals. Parthenogenesis usually gives rise to female offspring or sometimes an abnormal male.

In 1900 Jacques Loeb accomplished the first clear case of artificial parthenogenesis when he pricked unfertilized frog eggs with a needle and found that in some cases normal embryonic development ensued. In 1936 Gregory Pincus induced parthenogenesis in mammalian (rabbit) eggs by temperature change and chemical agents. Artificial parthenogenesis has since been achieved in almost all major groups of animals, by mechanical, chemical, and electrical means, though it usually results in incomplete and abnormal development.

Attempts at artificial parthenogenesis in humans have not yet been successful. The first cloned human embryo was produced in October 2001. Eggs had their own genetic material removed and were injected with the nucleus of a donor cell. They were then incubated under special conditions to prompt them to divide and grow. One embryo grew to six cells before it stopped dividing. The same experimenters also tried to induce human eggs to divide into early embryos parthenogenetically -- without being fertilized by a sperm or enucleated and injected with a donor cell -- but their efforts met with only limited success [1].

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].
Many primitive peoples believe that there are two methods of human reproduction: the ordinary animal one and a higher one rarely employed -- virgin birth [4]. One belief is that the rays of the sun can fertilize women. In this regard, it is interesting that ultraviolet rays can cause parthenogenesis in unfertilized eggs of sea-urchins. It is also believed that moon rays, wind, rain, and certain types of food can cause impregnation. In the 19th century the Trobriand Islanders of the western Pacific insisted that cases of virgin birth still occurred among them.

Further evidence for the possibility of human parthenogenesis comes from the mysterious phenomenon of dermoid cysts [5]. These are malformed embryonic growths or tumour-like formations occasionally found in various parts of the body, including womb, ovaries, and scrotum. They often contain bones, hair, teeth, flesh, tissue, glands, portions of the scalp, face, eyes, ribs, vertebral column, and umbilical cord. They are found in males as well as females, both young and old, including virgins. They appear to be undeveloped embryos and fetuses in various stages of growth. Loeb and several other researchers argued that dermoid cysts may be related to the parthenogenetic tendency of the mammalian egg, catalyzed perhaps by an increase in blood alkalinity. However, the body's parthenogenetic capacity is now very feeble and the generative centres lack the power to carry the reproduction process through to its proper conclusion.

It is possible that some cases of human parthenogenesis involve self-fertilization rather than true virgin birth, as there are cases of sperm being produced in women by vestigial, usually nonfunctional, male reproductive glands known as the epoöphoron (parovarium) and paroöphoron, which correspond to the seminiferous tubules of the testicles in males. In some instances, the magnetic influence and nervous excitement occasioned by attempted sexual intercourse may rouse into activity the latent, rudimentary male sex glands so that they secrete semen, resulting in impregnation [6].

Prior to the acceptance by the medical profession of the present theory of conception (epigenesis) in the middle of the 19th century, the ovist and aura seminalis theories prevailed, which can be traced back to Pythagoras. According to the ovist theory, the new organism is a product of the egg alone, and the spermatozoon and male progenitor are not essential to the reproductive process. According to the aura seminalis theory, the male supplies only a vital stimulus (an aura or emanation) which initiates the development of the ovum. The aura seminalis theory was rejected after it was established in 1854 that ova were fertilized by the actual entrance of the nucleus or head of the spermatozoa.

However, Loeb's experiments showed that for fertilization to occur, neither the sperm nucleus nor the spermatozoon itself need enter the egg, or even be in proximity to the egg. He replaced the sperm by alkaline solutions, ultraviolet rays, and other stimuli. Alexander Gurwitsch discovered in the 1920s that cells emit weak ultraviolet ('mitogenetic') radiation that can cause cell division in other cells at a distance -- a finding still resisted by mainstream scientists [7].

The power of sperm to cause fertilization is distinct from their capacity of hereditary transmission. In one experiment, a fertilizing enzyme (occytase) was isolated from spermatozoa and, when added to unfertilized sea-urchin eggs, caused them to develop. This substance is present in mammalian blood, since the addition of ox's blood to unfertilized eggs produced the same effects. Sperm therefore exercise two independent functions: they can trigger the segmentation of the ovum, and they may convey paternal genetic qualities. The former function can be replaced by chemical substances, while the latter can be dispensed with, in which case the offspring have purely maternal characteristics [8].

Eggs show at least a beginning of segmentation under normal conditions. But sperm, which are highly alkaline, appear to accelerate the process by compensating for the excessive acidity of the medium surrounding the egg rather than a chemical deficiency in the egg itself. An acid condition of the blood prevents the parthenogenetic development of ova in the ovaries, while increased alkalinity appears to favour parthenogenetic development [9].

Commenting on Pincus's experiments on artificial parthenogenesis in rabbits, G. de Purucker stated that the means employed had probably thrown the ova back to a condition identical with the hermaphroditism of the early third root-race. Since there is always a double sex in every human or animal of our day, the ova would develop from the double current innate in the mother rabbit and produce offspring much as the hermaphrodites did towards the middle of the third race [10].




References

J.B. Cibelli, R.P. Lanza and M.D. West, with C. Ezzell, 'The first human cloned embryo', Scientific American, Jan. 2002, http://sciam.com/explorations/2001/112401ezzell/index.html.
Raymond Bernard, The Mysteries of Human Reproduction, Mokelumne Hill, CA: Health Research, n.d., pp. 47-50, 56-63.
Ibid., pp. 3-10.
Ibid., pp. 11-28, 89-93.
Ibid., pp. 51-5, 117; F.H. Buzzacott and M.I. Wymore, Bi-sexual Man or Evolution of the Sexes, Health Research, 1966 (1912), pp. 32-4; Hilton Hotema, Secret of Regeneration, Health Research, 1963, ch. 204-205, 211.
Secret of Regeneration, ch. 208-210, 234; Gray's Anatomy, http://www.bartleby.com/107.
Peter Tompkins and Christopher Bird, The Secret Life of Plants, New York: Harper & Row, 1973, pp. 54-5, 197-9; R. VanWijk, 'Bio-photons and bio-communication', Journal of Scientific Exploration, vol. 15, pp. 183-97, 2001.
The Mysteries of Human Reproduction, pp. 42, 109.
Ibid., pp. 118-9.
G. de Purucker, Studies in Occult Philosophy, Pasadena, CA: Theosophical University Press, 1973, pp. 455-8.

from http://ourworld.compuserve.com/homepages/dp5/sex2.htm
 
From two years ago:
'Virgin birth' method promises ethical stem cells
09:30 28 April 2003
Exclusive from New Scientist Print Edition
Sylvia Pagán Westphal, Boston
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ParthenogenesisThe phenomenon that leads to "virgin births" in some species looks like a promising source of embryonic stem cells. Researchers are on the brink of obtaining human stem cells this way for the first time, and animal experiments suggest such cells are indistinguishable from normal stem cells.

In parthenogenesis, an unfertilised egg keeps two sets of chromosomes and begins developing as if it had been fertilised. Some insects and reptiles can reproduce this way but even though an electric or chemical stimulus can induce parthenogenesis in mammals, the resulting embryos die after a few days.

And that, according to its proponents, is the beauty of the technique as far as stem cells are concerned: it produces embryos that could never become human beings. So destroying these embryos to obtain stem cells would avoid the ethical concerns that have led to restrictions or bans on embryonic stem cell research in many countries.

However, while the technique works in mice and monkeys (New Scientist print edition, 26 October 2001), attempts with human eggs have not got far. Until now, that is. A team led by fertility specialist David Wininger at biotech firm Stemron of Maryland has grown parthenogenetic human embryos to the blastocyst stage, at which stem cells can be obtained. Cells taken from one of the embryos survived for a few days (Stem Cells, vol 21, p 152).

"It's the first time I know of parthenogenetic cells in humans," says Kent Vrana of Wake Forest University School of Medicine in North Carolina, whose team pioneered the work in monkeys.

Indefinite growth
The next step is to get the cells to grow in culture indefinitely: that is, to obtain a stem cell line. In monkeys, such a cell line has been growing for over two years, and it makes the human experiments all the more relevant.

According to Vrana, extensive analysis of the monkey cells suggests that they are indistinguishable from normal embryonic stem cells. "They are identical to ESCs by every known criterion we have tested," he says, adding that details will soon be published in a peer-reviewed journal.

A lot of work still has to be done to ensure any tissues made from parthenogenetic stem cells are absolutely normal, says Jerry Hall of the Institute for Reproductive Medicine and Genetics in Los Angeles. But he is optimistic. "Patients are so interested in this procedure, and we are confident enough in its feasibility, that we have been willing to store eggs for use as soon as safety and effectiveness is shown," he says.

Since eggs are needed to make parthenogenetic stem cells, one potential problem is that the technique could not be used to make matching stem cells for men or for women after menopause. Therapeutic cloning, by contrast, could provide matching stem cells for any individual.

However, because cells made by parthenogenesis have two identical sets of chromosomes, rather than one set each from the father and the mother, they have less variation in the surface proteins on cells that can trigger immune reactions. Wininger thinks it will possible to establish a bank of parthenogenetic stem cells that could provide cells to suit most individuals. And such banks would be much cheaper than creating stem cells from scratch for each individual.
from:
http://www.newscientist.com/article.ns?id=dn3654

lunamoth
 
Hi, Lunamoth--

Followed you here on the subject. One can only wonder as to why this is not more common knowledge.

InPeace,
InLove
 
Well, so far, other than the one description above I have not found any evidence of spontaneous parthenogenesis in humans aside from those in a religious context. With the current research in in vitro human parthenogenesis making no mention of those putative natural human virgin births, and also saying that mammalian eggs induced to be parthenogenic are not viable, I so far conclude those those cases were not verifiable and are probably just hearsay.

Maybe someone else has more information?

lunamoth
 
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