Controversies in Science/Was there a mitochondrial Eve?/A Critique of A complete Neanderthal Mitochondrial genome sequence determined by high-throughput sequencing: A Review
(Review Paper) Cited in Controversies in Science/Was there a mitochondrial Eve?/A Critique of A complete Neanderthal Mitochondrial genome sequence determined by high-throughput sequencing: A Review
Points Made[edit | edit source]
Scientists have yet to discover that Neandertals and Humans have interbred due to the lack of mtDNA integration. An analysis of pairwise differences between human mtDNA and Neandertal mtDNA was conducted to support the theory that hominoids came from a single source and were not interbred with Neandertals at any point.
- Physical evidence has been found to support hybridization between ancient human species and modern human species. From the time we split from chimps 5-7 million years ago, skulls have been found showing where hybridization occurred and where it did not. Human species such as Paranthropus and Australopithecus have died out due to newer species evolving. Skulls, stone tools, and evidence of culture gives some insight into the similaries between Homo neanderthalensis, archaic Homo sapein, and Homo sapien sapien.
Methods[edit | edit source]
A new method has been designed to improve the retrieval and analysis of ancient DNA. After extracting DNA (100-200mg) from Neandertal bones, in a clean facility, they performed genome sequencing analysis.
This analysis generated 39 million sequences.
From this it was determined that Neandertal mDNA is outside the range of variance seen in human mDNA.
The polymerase chain reaction was cloned and 103-112 clones were sequenced to determine the ratio of Neandertal to modern human mtDNA.
Results[edit | edit source]
Analysis of human mtDNA and Neandertal mtDNA found 206 differences, made up of 195 transitions and 11 transversions.
Based off this finding, they have determined that the two groups split 660,000 years ago (+ / - 140,000). They also inferred the possibility that Neandertal had a relatively small effective population.
Figure A shows Human mtDNA in green, Neandertal mtDNA in red and Chimpanzee mtDNA in blue to represent the pairwise sequence differences.
From this data we see that the humans mtDNA pairwise differences are bimodal and the differences range between 2 and 118. In comparison, the differences between Neandertal mtDNA and human mtDNA are between 201 and 234, and is unimodal, not bimodal. This data suggests that Neandertals are not within the same variations as humans.
When comparing HVRI and HVRII only, the differences between human mtDNA and Neandertal mtDNA begin to overlap in HVRI by a larger margin in HVRII (which we can see in Figures B & C). This suggests that mtDNA comparisons are convoluted by multiple substitutions if only viewing these samples, this does not specifically suggest that human and Neandertal DNA overlaps.
References[edit | edit source]
- Green, R., Malaspinas, A., Krause, J., Briggs, A., Johnson, P., Uhler, C…. Paabo, S. (2008) A complete Neadertal Mitochondrial genome sequence determined by high-throughput sequencing: A Review]]. Cell. 134(3) pg. 416-426. Retrieved March 22, 2011. From: http://library.mtroyal.ca:2048/login?url=http://dx.doi.org/10.1016/j.cell.2008.06.021