Many Biology texts say chimp and human
DNA sequences are 95-99% identical.
This 95-99% figure is factually erroneous due to its:
RANK CHERRY-PICKING In comparing chimp and human genomes,* commonly-used "low-complexity sequence masking" excludes many non-aligning DNA segments, understating disparities between the two genomes.
STATISTICAL SLANT Focusing only on the most similar portions of chimp and human genomes exaggerates their total actual harmony.
OVERRATED SYNC The longer the DNA sequence segments compared, the lower the percentage of match-up between portions of chimp and human genomes.
HIGH DISCREPANCY 23% of chimp and human DNA sequences show no similarity. Chimp and human Y-chromosome DNA sequences differ by over 30%, or about as much as human and chicken autosomes* differ. 83% of amino acid sequences in chimp chromosome 22 differ from those in its human chromosome 21 counterpart.
CONFLICTING DESCENTS Biochemical phylogenies* of chimps, humans, gorillas, and orangutans contradict their standard anatomical phylogeny 40% of the time.
BLOATED PERCENTAGE Counting the gaps between closely aligning strands of chimp and human DNA sequences deflates the overall identity ratio between their respective genomes to 70-87%.
RISKY SNAP JUDGMENT Any assured correspondence between the two genomes is premature and arbitrary. Unacknowledged functions of now-omitted, non-aligning DNA sequence sections may revolutionize comparisons.
*genome – an organism's genetic constitution
*phylogenies – evolutionary trees of "common ancestry," based on either comparative biochemistry or comparative anatomy
*autosomes – chromosomes whose genes are not sex-linked
— Chromosome-2 Fusion Hypothesis —
The Chromosome-2 Fusion Hypothesis says that chimp and human lineages from a common ancestor split when chromosomes 2A and 2B in the 24-chromosome chimp genome
fused to form chromosome 2 in the henceforth 23-chromosome human genome.
These errors of fact discredit this Fusion Hypothesis.
Contrary to Fusion Hypothesis predictions, the 789 nucleotide*-long DNA sequence at the alleged human chromosome-2 fusion site is not exceptional, but instead common (80% or greater in similarity) to DNA sequences on most other human chromosomes.
NOT CONGRUENT Chimp DNA sequences nowhere closely match the 789 nucleotide*-long DNA sequence at the postulated human chromosome-2 fusion site.
NOT LOCALIZED Telomeres consist of DNA, RNA, and proteins. They exist at the ends of chromosomes to protect them. At the human chromosome-2 site where chimp chromosomes 2A and 2B purportedly fused to form human chromosome 2, are about 300 telomere sequences, a density cited as evidence for the claimed union of the two chimp chromosomes into human chromosome 2. Yet chromosomes
contain many internal telomere sequences in addition to their telomere end-caps. Human chromosome 2 has a total of over 91,000 such internal telomere sequences. The unremarkable 300 at the putative
fusion site suggest no special fusion event.
NOT COMPLEX The supposed human chromosome-2 fusion site does not display the
expected highly-ordered structure of multiple standard fused telomeres from the ends of the two proposedly-united chimp chromosomes.
*nucleotide – a unit (half a base pair) in DNA consisting of a phosphate group, a 5-carbon sugar ("deoxyribose") and a nitrogen-containing base (either adenine, cytosine, guanine, or thymine)