Stem Cell Fraudster May Have Actually Made Breakthrough 206
Otter writes "Woo Suk Hwang's career swung from fame over his lab's claim of the first stem cells from a cloned human embryo to humiliation when the results were found to be fake. Research at Harvard on Hwang's cells has found that they are actually parthenogenic lines derived from eggs -- perhaps a more important and difficult achievement than what he had been claiming! 'Researchers said that the distinct "genetic fingerprint" of the stem cells means they may be the first in the world to be extracted from embryos produced by the so-called "virgin birth" method, or parthenogenesis. This happens when eggs are stimulated into becoming embryos without ever being fertilised by sperm, and has been achieved in animals. However, before Hwang, no one had managed to produce a human embryo using parthenogenesis which lived long enough to allow the extraction of viable stem cells.'"
Original paper (Score:5, Informative)
Re:ignorance in need of a cure (Score:5, Informative)
You mean parthenogenic. It means conception of an egg into an embryo without the male sperm (or any other male fertilization).
Yes, in some species, this occurs in nature.
(See? We men aren't useful for much except for fixing cars and hauling around heavy objects.
Because it wasn't previously thought possible.
Re:Jesus? (Score:1, Informative)
In order to make male babies, you need a Y chromosome(which
women don't have).
A Better Link (Score:3, Informative)
Re:Um, sorry to correct the writer but... (Score:1, Informative)
Simple language version (Score:5, Informative)
I'm shooting for the non-geneticist version:
Basic Version:
a normal human cell has 2 copies of 22 non-sex chromosomes, and 2 sex chromosomes. The "copies" are almost certainly NOT identical to one another, but basically similar. These cells are "diploid" (having 2 of each chromosome) and are considered "somatic cells".
During normal reproduction, each person will contribute a "germline cell", an ova or a sperm, in which only 1 copy of each chromosome exists ("haploid"). These germline cells merge to create a "zygote" (which is diploid), which eventually becomes an embryo.
Parthenogenetic reproduction takes a germline cell, and duplicates the genetic material, making a diploid out of a haploid. Such replication happens with normal cells during the process of cell division ("mitosis"), so the real trick is (1) convincing the cell to do this duplication outside the cell division process and (2) convincing the cell that it is no longer a differentiated (specialized) cell, but instead a stem cell.
One interesting result here is that the parthenogenetic cell is NOT a clone of the parent cell - it will have two copies each of ONE of the copies of each chromosome from the parent, determined effectively at random. In some ways this means a parthenogenetic stem cell is less valuable than a cloned stem cell - it will not be a 100% match, though it will not contain any DNA foreign to the donor. In other ways it opens up all sorts of new areas of study.
One particular result is that it opens the opportunity for recessives to be studied. (Chromosomes have genes, each that code various proteins that run the bodies mechanics. Most people will therefore have two copies of every gene (having two copies of the chromosomes). Those genes may not be identical. Some genes only have their effects seen ("express") if there isn't another, different, copy of the gene present, and are called recessives. (blue eyes are a common example: A blue-eyed person has both genes as expressing "blue". Two blue eyed parents, having only the "blue" gene (hah!) to pass on to a child, will have a blue-eyed child (barring mutation). (Of course, the body is a big nasty mess of self-referencing code with lots of gotos, so examples tend to be oversimplified). Anyway, most recessives tend to be fairly rare in expressing, since any dominant gene will cover them up. Many recessives are bad. (Cystic Fibrosis is the most common example: 1 bad gene, okay. 2 bad genes: You die) A parthenogenetic process would allow for the study of recessives because you can take ova from a carrier (someone who has 1 copy of the bad gene), find one with the defective gene, put it through the parthenogenesis process, and bam, able to study the effects free of the presence of any other (different) copy of the gene.
Fun Fact: For 22 Chromosomes, people have two copies of most genes. Sex Chromosomes are not created equal. The X chromosome (every human has 1) has valuable and nifty genes. The Y chromosome (only in men) has very few genes (relatively). As a result, on Men X chromosomes express all recessives, and not on women. (The common example here is red-green colorblindness. Men with a defective gene are out of luck: Color-blind. Women with a defective gene get by if the other copy of the X chromosome has a functioning one. Result: Men are much more likely to be red-green color-blind.
Some papers a few months ago got some press for exploring the possible effects of this. (Men can serve as a "testing ground" for new mutations on the X chromosome, while women can serve as a judge of whether they are valuable without taking on the extra risk. Practiced through natural selection.)
Fun Fact #2: Women's cells don't just function with twice the number of X chromosomes though (We tend to react poorly to extra copies
Re:Um, sorry to correct the writer but... (Score:3, Informative)
You can read the full article here [wikipedia.org]
Re:Um, sorry to correct the writer but... (Score:1, Informative)
Re:Color-blindness (Score:3, Informative)
Her daughters will only carry a defective gene, but unless the father is also color-blind, the daughters will not be color-blind.
Re:He was not the first one. (Score:3, Informative)