| 摘要 |
<p>Pregnancy in animals such as the pig usually does not continue to term when there are only a few embryos in the uterus. Currently available technology for maintaining pregnancy involves a series of hormone injections, and the failure rate is high. It has now been discovered that pregnancy can be maintained by complementing fertile embryos in the uterus with additional embryos that aren't expected to survive the full term of the pregnancy. Particularly suitable are parthenogenetic embryos, formed by activating and diploidizing unfertilized oocytes. The carrier embryos are engrafted into the uterus of a surrogate female, and the pregnancy continues to term without further intervention - even if the number of fertile embryos is below the minimum litter size. This provides valuable biological material that can be used for transplantation, the production of pharmaceuticals, and for agricultural use.</p> |
