Sunday, December 11, 2016
'Cow Gene' Explains Failure of Cloned Genes
A recent study conducted at the University of California showed a cow gene that demonstrated why most clones fail. Cloning mammals has proven to be a challenge; however, it was just twenty years ago that Dolly the sheep was successfully cloned. Using the technique of somatic cell nuclear transfer was originally how Dolly was cloned, or rather when a nucleus from an adult cell is transferred into unfertilized egg that has had its nucleus removed, and then begins cell growth by an electric shock. Recipient mothers then carry the transferred embryos until the clones are born.
The process of cloning cattle can be used to study development in mammals, and is important technology for agriculture; however, the success rate remains very low - less than ten percent of cloned animals survive until birth. Losses of the cloned animals may be due to a variety of reasons: failure during implantation of the embryo, embryonic death in general, or the possible development of a defective placenta. However, with recent developments into why there is so much reoccurring failure, it may be possible to get to the root of the issue. Scientists used RNA sequencing in order to look at gene expression in cows that had been cloned during implantation and attempt to understand the molecular mechanisms that lead to such a high rate of failure during pregnancy.
In this study, the researchers studied tissue from cloned cow embryos--all derived from the same cell line--at 18 and 34 days of development, as well as the corresponding endometrial lining of the pregnant cows. They also used cows that were not cloned, conceived using the process of artificial insemination. By use of RNA sequencing, multiple genes were found to be expressed abnormally, that could potentially lead to the high mortality rate of cloned embryos, as well as their failure to be implanted in the uterus and to develop a normal placenta. Researchers were able to find anomalies in expression of more than five thousand genes looking at the extra embryonic tissue of those of the cloned cows by day 18. Hopefully researchers will be able to use this find to uncover more developmental issues of the cloned embryo, and eventually lead to a higher survival rate.
As much as I find cloning of genes interesting, I do wonder about the possible risk factors involved, besides those listed above. It makes me very curious to see the future of these processes, and what could potentially come out of then. I also do think that cloning of genes as a whole could be a very useful practice, especially with genes that may be correlated to positive human growth and health. I'm sure that there is a lot left to learn about the future of cloning, and I am excited to see where it goes.