Human Parthenogenesis: The Virgin Birth

Last night on House, M.D., an interesting medical synopsis was proposed: Human Parthenogenesis, or the virgin birth. I think it may have had something to do with the proximity to Christmas and the legend of the virgin birth. This particular scenario, which is greek for "virgin creation", is an asexual form of reproduction found in females where growth and development of offspring occurs without male involvement. In other words, human parthenogenesis is precisely the phenomenon that is proposed in the bible during the birth of Jesus.

Parthenogenesis occurs naturally in some plants, invertebrates, and vertebrates. Although there have been no known cases of naturally-occurring parthenogenesis in wild mammals, it has been induced in the laboratory in a few circumstances [1,2]. Typically, however, parthenogenesis in mammals results in abnormal development because mammals have "imprinted" genetic regions, where certain genes are expressed that come from either the mother or the father. In other words, mammals possess two copies of their genome, one copy inherited from each parent at fertilisation, but gene expression occurs from only set of genomes [3].

That being said, on June 26th 2007 the International Stem Cell Corporation announced they were intentionally creating human stem cells from unfertilized human eggs using parthenogenesis. On December 18th 2007 this group published an article that stated they had successfully used parthenogenesis to produce human stem cells that are homozygous in the "HLA" region of the DNA [4]. In lay terms, this group successfully developed a parthenogenesis technique that can be used to create embryonic stem cells without the use of embryos, in which the "HLA" region (region containing the information about the Histocompatibility Complex, or cell surface markers that can identify your cells from other cells) is similar to the donor. In this way, tissues grown using their technique are not rejected by donors like other forms of tissue transplantation. It is quite a feat, but by no means is it naturally-occuring human parthenogenesis.

In summary, parthenogenesis is a naturally-occuring phenomenon in many species of plants and animals; however, human parthenogenesis has only been performed in the laboratory, under strict experimental circumstances, and has by no means been used to grow an entire human being.


References

1. Pincus G. and Shapiro H., (1940) Further studies on the parthenogenetic activation of rabbit eggs, Proc US Nat Acad Sci, 26:163-5.

2. Kono T., Obata Y., Wu Q., et al., (2004) Birth of parthenogenetic mice that can develop to adulthood, Nature, 428:860-4.

3. Wilkinson L.S., Davies W., Isles A.R., (2007) Genomic imprinting effects on brain development and function, Nat Rev Neurosci, 8(11):832-43.

4. Revazova E.S., et al., (2008) HLA homozygous stem cell lines derived from human parthenogenetic blastocytes, Cloning and Stem Cells, 10(1):11-24.