Medicalnewstoday released an article about sexual reproduction and crossing over. Neil Hunter and his researchers at the UC Davis College of Biological Sciences have been studying a specific gene. Numerous amounts of genetic studies show that when women make more crossovers they tend to have more children. Studies also show that when a low amount of crossovers are formed gametes may have the incorrect number of chromosomes, and this can cause infertility or chromosomal diseases for the baby. This gene, Rnf212, is said to control crossover numbers in humans and is vital for crossing over in cells of mammals. Hunter explains in a quote in the article that there is not a distinctive site for crossing over to occur since it can occur almost anywhere on a chromosome. He also mentions that there has to be on and that there always is one way. After a series of experiments in mouse cells the research team found out that Rnf212 protein can define where crossovers will occur. The point of crossover is found when the protein binds to one or two recombination sites on each chromosome, which is where it triggers the buildup of protein structures that complete the cutting and entwining of DNA. When the researchers examined mice without the gene for Rnf212, they found out that the mice were sterile, and that a low amount of crossovers happened. This discovery about the infertile mice could be a way to understand a few causes of infertile humans.
http://www.readcube.com/articles/10.1038/ng.2559
http://www.nature.com/ng/journal/v45/n3/full/ng.2541.html
I found this very interesting because I was not aware that there was actually a gene that controlled the amount of crossing over that occurs in a person. Also, I did not know that a deficit in crossing over can cause a person to become fertile. I definitely am interested to see if in the future, scientists will be able to manipulate crossing over genes in fertile humans to give them another shot at reproduction.
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