A report published in Science Magazine, and reviewed on TheScientist.com suggests that there is a striking link between mitotic aneuploidy and a nucleotide variant (SNP rs2305957) of chromosome 4 of maternal genomes. What is the significance of this, and what does it all mean? Well, since aneuploidy, or having the incorrect number of chromosomes in a cell, is the most common reason for failed pregnancy, the importance of this discovery is obvious. Not so obvious, however, is the fact that the team doing the study found that this single nucleotide variant's frequency reaches up to 45% in human populations. Coupled with the fact that this variant is completely absent in Neanderthal genomes, this may suggest that positive selection in human evolution has allowed this gene to proliferate.
The question not answered by this study is the purpose of the rs2305957 variant. Dmitri Petrov, a scientific researcher at Stanford University, believes that the variant might have established paternity confusion. This hypothesis suggests that when males were unsure if a child belonged to them, they would care for all of the children equally, benefiting the group as a whole. Whether this, or the many other theories circling this new discovery are true, is unknown. But the fact that evolution allowed a gene variant that reduces the number of successful pregnancies to proliferate, is puzzling to say the least.
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