Permanent LinkPosted: Fri Dec 12, 2008 10:13 am 
http://news.nationalgeographic.com/news ... rth-2.html

Ok. I know that you are all as fascinated by this subject matter as I am, not. Still it's a really interesting subject. The correct term for it is parthenogenesis. This means a female egg will self fertilize without the presence of a male and she will give birth.

This has been know to happening with insects, amphibians and reptiles. Usually this happens after long periods without the presence of any males. Recently just to show you how far behind our science is, they realised that sharks have this ability, maybe not all sharks, but at least two species, including the hammerhead shark.

A female shark that had been in an aquarium died, and upon autopsy it showed that she was carrying a fully formed pup. Neat.

Could this happen in other species? Probably, but since science has not been looking for virgin births, when they see it, they probably attribute it to other things, such as long term sperm storage, yeah. If you are not looking for proof of a phenomenon, how can you prove it's existence?

So if this happens with sharks, reptiles, and other amphibians could it ever happen with mammals? With this is an interesting question, and I don't know if they are looking into this, because their science tells them that it's not likely, that is of course until it happens. If you are not looking for a phenomenon, then you won't recognise it even if it does happen.

The problem with mammals is of course by their very nature, they often take care of their young, and many live in communal groups, whales, bats, humans, etc, so the circumstances that would bring about parthenogenesis in other species probably does not present itself as readily in mammals.

I think it's interesting and something that science should try to look into. Since we know that when this happens the offspring has fused chromosomes of the mother, then we could genetically test mammals to see if this phenomenon had happened in any species that exist alone for long periods of time. Here is the story about the shark and it gives you a lot to think about.

Quote:
Chapman and his colleagues generated a DNA fingerprint for the mother shark and her pup fetus with a procedure identical to a human paternity test.

Ordinarily, a shark's DNA contains some genetic material from its mother and some from its father. Tidbit's pup, however, was not ordinary.

"Every part of the fingerprint of the embryo comes from the mother," Chapman said. "In other words, there is no genetic material from a father."


Since we now know that this does happen in nature, what we don't know are what are the mechanism that trigger this effect? Is it a rear occurrence or something programed in all genetics to keep the species going? There are a lot of unanswered questions, because if you know what triggers the process, then you can say if it could happen in other species.

Quote:
Examples have been documented in komodo dragons, pythons, rattlesnakes, chickens, and turkeys.


This article is saying that parthenogenesis would not be possible with humans, but I don't believe that for a second. Until we understand more about the process, what triggers it, and how do we know what the cells would be capable of? All humans start off as female embryos, and then with the male hormone they become male vs female. How do we know what processes would kick in under these circumstances in nature? Currently however science has not reported parthenogenesis in any mammals, but till a couple of years ago, they had not reported anything in sharks either, and thought that it was impossible, till it happened.

Quote:
Parthenogenesis is not possible in humans because if all the genetic material comes from the mother, certain genes will be switched off, and the embryo won't develop.

"For sharks in captivity, [parthenogenesis


http://www.newscientist.com/article/dn4909

Quote:
A mammal that is the daughter of two female parents has been created for the first time.

Until now such a feat had been considered biologically impossible. But the mouse, called Kaguya, was born without the involvement of any sperm or male cell - only female eggs were needed.

In the same way that the birth of Dolly the sheep in 1997 shattered the dogma that an adult cell could never be reprogrammed to make a new individual, the fact that Kaguya lives challenges another one of long-held rule: that two mammals of the same sex cannot combine their genomes to give rise to viable offspring.


If we can do this in the lab, why could this not naturally occur in nature, when we see that there is a natural process in nature that does make this possible for other species? Could it be that we are not looking?


http://www.independent.co.uk/news/scien ... 60837.html

Quote:
The mouse was generated from two unfertilised eggs and its birth has demonstrated for the first time that it is possible for mammals to be born by the "virgin birth" phenomenon of parthenogenesis.

Scientists said the mouse developed normally to adulthood and had offspring of its own by normal sexual reproduction, showing parthenogenesis could work on warm-blooded mammals, including humans.


What we need to do to set science on it's ears once more is to find the process working in nature, which I do believe is fully possible. Again however, we need to know more about what starts the process, so that we can look for optimum circumstances where that can be achieved? Is it just removing males from the environment for long periods of time? Does the female need to be isolated also? Are all creature capable of this, or just some special ones within the species? What tells the process internally to start?

http://www.belfasttelegraph.co.uk/news/ ... 44103.html

Quote:
Dr Paulo Prodohl, head of the Queen's research team, said: "The findings were really surprising because as far as anyone knew, all sharks reproduced only sexually by a male and female mating, requiring the embryo to get DNA from both parents for full development, just like in mammals.

"The discovery that sharks can reproduce asexually by parthenogenesis now changes this paradigm, leaving mammals as the only major vertebrate where this form of reproduction has not been seen."

Parthenogenesis - where females give birth to fully formed young without their eggs being fertilised by a male - has very occasionally been seen in some vertebrate groups such as birds, reptiles and amphibians, but has never before been seen in major vertebrate lines such as mammals or sharks.

The most likely form of parthenogenesis leads to less genetic diversity in the infant than the mother, leading to fears that genetic diversity could be eroding in shark populations if females have difficulty finding mates.




Till science can answer these questions conclusively, I don't think it's fair for them to presume what is and what is not possible at this stage, because we don't know enough about what starts the process, we just know that it is capable of happening.


Last edited by gangstalking on Fri Dec 12, 2008 11:15 am, edited 1 time in total.


 Profile  
 





 

Author

Blog: View Blog (284)

Archives
- July 2009
MJ makes sainthood
   Tue Jul 07, 2009 5:48 pm
Psi Ops
   Sat Jul 04, 2009 6:02 pm
A baiting we will go.
   Thu Jul 02, 2009 10:52 pm
Are informants stupid?
   Thu Jul 02, 2009 5:38 pm

+ June 2009
+ May 2009
+ April 2009
+ March 2009
+ February 2009
+ January 2009
+ December 2008
+ November 2008
+ October 2008
+ September 2008
+ August 2008
+ July 2008
+ June 2008
+ May 2008
+ April 2008
+ March 2008
+ February 2008
+ December 2007
+ November 2007
+ October 2007
+ September 2007
+ August 2007
+ July 2007
+ June 2007
+ May 2007
+ February 2007
+ January 2007
+ December 2006
+ November 2006
+ October 2006