This post was originally posted on blogspot.com on November 24, 2012
The following article on BBC News describes a new technology to create egg cells, and although this technology currently only works for mice, I think this is an important development. In this post I will discuss why discoveries like this one are important for space colonization programs. In an earlier post I discussed some applications for artificial reproduction in space colonization.
My main point in that post was the need of a large gene pole. A low degree of genetic diversity will lead to inbreeding, which is usually associated with increased risk of genetic disorders. Unless we will apply strict genetic screening of immigrants, space populations will likely only exist for some generations. Even with genetic screening, we have the problem that most people are carriers of a few defect genes. The only way to solve the problem of a small gene pool, is to increase diversity. This can be done in two-way: massive immigration or import of human gametes.
Large scale immigration has multiple side issues: from a technical point of view we have to deal with the bottleneck to space, current rocket based space launch systems have limited capacity to send people to space. (We believe that all proposals for non-rocket space launch, are unlikely to developed soon, see also this post.) All best case scenarios predict that only a few hundred people can emigrate to space each year.
Another issue related to mass immigration is social-cultural and political. Space communities will most likely have very restrictive admission policies, and will select only those potential immigrants on whether they have certain desired qualifications and whether they do share the political ideology of a particular space colony. For example a more socialist oriented space colony is not likely to be willing to accept immigrants who are opposed to socialism.
The second solution for increasing genetic diversity is by importing human gametes. Human sperm can easily be collected on Earth, space governments could offer reasonable cash amounts to men in return of their sperm. Once collected, sperm is easily stored and transported, one launch could easily carry the sperm of several thousand males. The collection of human egg cells is much more difficult, eggs or ovary tissue can only be collected through surgery. It is clear that buying human eggs is much more expensive than human sperm, we have now also to pay for the surgery.
However this problem would be solved if we would be able to make egg cells from skin tissue, which can be collected in almost every reasonable hospital in the world. The procedure of collecting skin tissue is much less intrusive for women. Tissue cultures are just like sperm samples easy to store and transport into outer space.
Sperm donation and artificial egg cells will make it possible for Space communities to develop gene banks with high genetic diversity without the difficulties arising from (mass) immigration.
Artificial sperm is also possible http://www.bbc.co.uk/news/health-14404183