Saey, Tina Hesman. "Monkeys Born with Edited Genes." Science News. N.p., 1 Feb. 2014. Web. 11 Jan. 2015. <https://www.sciencenews.org/article/monkeys-born-edited-genes>
Recently, two female monkeys were the first to have their own genes edited by scientists. The hope was to find ways to cure human brain mutations by studying them in monkeys. By genetically engineering the monkey's embryos in order to "edit their genes", the resulting monkey would have brain mutations very similar to those found in humans. To do this, Chinese scientists inserted mRNA into a single celled monkey embryo that produces the enzyme Cas9. This enzyme, first found in bacteria, defends against the bacteria's virus's by cutting up foreign DNA. Putting this enzyme into the monkey's embryo would snip sequences of DNA and cause mutations. The single celled embryo would then divide and each resulting cell would contain the mutation. The genes that were mutated were NrOb1, a gene involved in embryonic cells and determining the organisms sex, Ppar-gamma, a gene involved in regulating metabolism, and Rag1, a gene involved in the organisms immune system. Out of the eight embryo's that were altered, only two female monkey's named Mingming and Ningning were born with the mutations. However, in addition to being able to study these mutations more closely, scientists hope that a process similar to the one of editing genes to cause mutations will help remove mutations from people in the future.
This relates to our study of mutations and genetic engineering, specifically in the sense of genetically modified organisms. Organisms that are genetically modified are organisms whose genes have been modified by artificial means. In class we learned how scientists can insert genes from one organism into another organism, mostly by using plasmids and restriction enzymes. This experiment, however, took genetic engineering a step further. Scientists discovered a way to directly alter the genes of monkey embryo's with the enzyme Cas9. Additionally, the enzymes job to cause mutations also relates to our study of mutations in class. A mutation in a sequence of DNA can occur when there's a substitution, deletion, or insertion of bases in the nucleotide sequence. The enzyme did this by snipping the DNA, most likely causing a deletion in one or more of the bases.
Do you know why only two of the eight were born with the mutations, or is it just by chance that that happened?
ReplyDeleteThere is not an exact reason, however, scientists have a possible answer. The idea in the experiment was to put the DNA cutting enzyme in the single celled embryo so every cell resulting from cell division would have the same mutations. Instead, in some of the embryo's, the enzyme didn't start snipping the DNA until the single cell had divided, causing many cells to remain unchanged and without mutations. Therefore, the monkey embryo would have developed without mutations and the resulting monkey would be born without mutations.
DeleteWhat would the process be to remove these mutations, and are there plans to try this with a similar test?
ReplyDeleteAs someone said in the article, the same technique to add mutations, could be the same technique that would remove mutations. Most likely, the process would involve using a DNA cutting enzyme to delete bases that cause mutations, and if possible, paste new bases into the sequence. Another article also described using a Zing-finger Nuclease, a molecule that can find a specific sequence in the DNA and cut the strand at that spot. Scientists have been investigating this idea within different types of mutations, but so far, this idea is sill developing. Most plans coming up are ones that will be studying different mutations in animals instead of conducting experiments to get rid of them.
DeleteThe link to the additional article I used to find research is here- http://en.hdbuzz.net/038