MISGUIDED - NATURE & SCIENCE

NATURE & SCIENCE MISS THE MARK

I was thinking about my previous post and it seemed to me the obvious answer to determining animal phylogeny stared me in the face.  The data I had cited from Francis S. Collin's book, The Language of God, seemed to provide proof of the point I have been trying to make in many evolutioninsights.blogspot.com  posts.  On page 127 his Table 5.1 compares the liklihood of finding comparable DNA sequences of humans in other organisms.  It makes the comparison, first of protein coding genes from humans with six other species, then randomly selected DNA from between genes of those species.

Human compared        Protein coding        Random DNA
with                             DNA                     between genes

Chimp                         100%                    98%

Dog                              99%                     52%

Mouse                          99%                     40%

Chicken                        75%                       4%

Fruit fly                         60%                     -0%

Roundworm                  35%                     -0%


Your first thought might be that the protein coding genes make more sense to use for determining relationships.  That is probably the rationale the two flawed studies proposing Ecdysozoa (in Nature, 1997) and Lophotrochozoa (in Science, 1995) used in selecting 18S ribosomal DNA.  But there would be stringent selection to keep that DNA from changing, with a proportionality to its functional importance.

The random DNA from non-coding regions would lack selection and thus could change proportional to the number of generations between the two being compared.  Thus if liklihood percentages are apportioned inversely to generation time in constructing the branch lengths from common ancestors, an ancestral tree could be determined better than by any other available method.  Of course, pairwise comparisons would need to be made for each other possible combination of species considered.

Looking at the data in the table, because mice have shorter generation time they would accumulate more changes since our common ancestry and may thus actually be closer in common ancestry to us than the dog, even though there has been greater change in their between genes DNA.  The big jump between the chicken and the mammals is due to the much greater antiquity of the separate lines from early ancestral reptiles.  With very low liklihood of DNA relationship the accuracy of relationship determination is greatly reduced and fossils and anatomical analysis may be more useful.

I would send this as letters to the editors of Nature & Science, but I doubt they would be any more likely to publish them than my previous submissions many years ago.  Too bad, it might have prevented the Ecdysozoa error which put the roundworm and fruit fly in relatively close relationship.  The same method used for the Lophotrochozoa is consequently almost equally erroneous.

Science and Nature are two excellent science journals.  I am puzzled by the fact that the error has not been corrected.  Perhaps others read it much as I have in the past when reading things I am not very familiar with, assuming the research finding are accurate.  I did so despite the fact that long ago I realized not everything in print, or on internet, must be correct.

Joseph G. Engemann   Emeritus Professor of Biological Science, Western Michigan University, Kalamazoo, MI     March 7, 2015