Luskin still doesn't get DNA sequence analysis

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Sujet : Luskin still doesn't get DNA sequence analysis
De : rokimoto557 (at) *nospam* gmail.com (RonO)
Groupes : talk.origins
Date : 30. Jun 2025, 17:01:28
Autres entêtes
Organisation : A noiseless patient Spider
Message-ID : <103uccq$28tfr$1@dont-email.me>
User-Agent : Mozilla Thunderbird
https://evolutionnews.org/2025/06/on-human-chimp-genetic-differences-the-critics-misstate-my-arguments/
He is claiming that his critics are not addressing his claims or misstating them.  Luskin is falsely claiming that the 1% difference between chimp and human genomic DNA that had been determined for the sequence that was compared in order to determine the evolutionary relationship between extant life forms is some type of Icon of evolution.  It is just what the sequence difference was.  It wasn't the 1% number that determined that chimps are the most closely related species to humans it was how that 1% difference related to all the other species that we had the same sequence for and could compare them.
Coding sequence is still 0.7% different between chimps and humans, and the sequence around the genes that we can compare are between 1 and 1.8% different.  We can't use a lot of the sequence around the coding sequence to compare extant species to each other because it is so different between species that we can't compare it accurately.  I took around 800 base-pairs of the tyrosinase exon 1 coding sequence and the following 900 base-pairs of the first intron.  Chimps and humans were 99% similar by BLAST for this sequence.  Green monkey was 95% similar for the sequence compared to humans, but the coding sequence was less than 3% different and the intron sequence was almost 9% different (there were also a couple of indels in the intron).  I tried the same sequence for mouse and BLAST would not align the intron sequence.  It was just too different.  Even under BLAST for more relaxed conditions it would only align bits of the intron in around 60 base-pair pieces where there was enough similarity where they might be the same sequence (many of these short matches were not the same sequence and were on other chromosomes of the genome assembly).  The 826 base-pairs of coding sequence was 87% similar, but the intron sequence was not matched up. It might be expected to be around 60% similar if you could align it, but any alignment likely would not be that accurate.
This just means that the sequence that we determined to be around 1% different (coding sequence) is the sequence that would be used to determine evolutionary relationships between mammals.  It is the sequence that can be used to determine that chimps are the most closely related species to humans that exist on this planet today.  But outside of mammals the accuracy of coding sequence decreases because of the degenerate code and multiple substitutions at the third position of codons that you can't tell if they have been mutated multiple times or not.  You can only use noncoding sequence like introns to compare closely related taxa because they change too fast to be useful.
The additional sequence that Luskin is beefing about was sequence that we could not obtain in all taxa, and it is still sequence that can't be accurately compared between the taxa with complete genome sequences because of the repetitive nature of the sequence and the rapid copy number variations between species and the rapid evolution of the sequence of the heterochromatin repeats.
Luskin is literally beefing about something that never mattered, and still does not matter.
The mitochondrial DNA sequence is 8.9% different between chimps and humans and still indicates that chimps are the most closely related species to humans.  In the 1980's mitochondrial DNA was the first sequence used to determine that of the other great apes chimps were our closest relative.  It wasn't the 1% genomic coding sequence difference. For the tyrosinase sequence that I used in the above analysis both gorilla and chimps are 99% similar (16 mismatches with Gorilla and 20 mismatches with chimps) by blast alignment.
Ron Okimoto

Date Sujet#  Auteur
30 Jun17:01 * Luskin still doesn't get DNA sequence analysis4RonO
30 Jun19:44 `* Re: Luskin still doesn't get DNA sequence analysis3John Harshman
30 Jun21:32  `* Re: Luskin still doesn't get DNA sequence analysis2RonO
1 Jul04:02   `- Re: Luskin still doesn't get DNA sequence analysis1John Harshman

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