Saturday, October 19, 2013

Human Chromosome 2 Fusion Theory Shown Wrong

The claim man evolved from a common ancestor with apes has bee recently supported by that claim that the human chromosome 2 is  an end to end fusion of chimp chromosomes 2a and 2b. This theory was proposed as a way to explain the fact that humans 46 chromosomes and all  apes 48. The evidence for the theory is rather weak because if the DNA sequences were originally centromere, and telomere sites they would are highly degraded possible time span.
This claim ignores the fact that such a mutation would probably render the individual infertile with rest of his species and if he or she were lucky enough to find a mate with the same fused chromosome the offspring that would be produced would have trouble finding a compatible mates So survival od such a mutation let alone dominance is highly improbable.
Furthermore there are no cases in mammals identified as telomere-to-telomere fusion. Chromosome fusions documented in living mammals involves satellite DNA . The fact is that telomeres have end caps called the shelterin protein complex that prevent  telomere-to-telomere fusion.
Chromosome fusion theory has another in the fact that DNA sequences in the area around the alleged  human chromosome 2 fusion site lack the  expected similarity between humans and chimps. There is even unexplained "missing"  chimp DNA in the area. To make it worsts alleged fusion site is surrounded by many functional genes that are not in the ends of the ends of chimpanzee chromosomes 2A or 2B.
The final fatal flaw in the chromosome 2 fusion theory is that the alleged fusion site is inside the DDX11L2 gene.  This gene contains three primary exons and serves several regulatory functions. In fact it is a highly expressed and complicated gene not found in apes.
If the human chromosome 2  were indeed a result of an end to end fusion from two chimp chromosomes 2a and 2b were would expect to find the fusion site in fairly good shape and surrounded by DNA sequences highly similar between humans and chimps but we do not. We also find a unique highly functional gene going right across the alleged fusion site. Thus this so called evidence for a human-chimpanzee common ancestor and human evolution can be considered falsified, that is has been shown to be wrong.

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