In a previous post I noted that a relatively new book by Daniel Kuebler, professor of biology at Franciscan University of Steubenville, cites some common but debunked evolutionary arguments. Many of these I dealt with in my chapter “Universal Common Descent: A Comprehensive Critique” in the 2017 book Theistic Evolution: A Scientific, Philosophical, and Theological Critique. As my chapter says, people often claim that our ability to construct phylogenetic trees provides evidence for common ancestry. And indeed, Kuebler makes this argument:
Additional compelling support for universal common descent can be found by looking at the evidence for common descent on the various branches of the evolutionary tree. While it would not fully establish universal common descent, evidence that all primates are related by common descent or that all mammals are united by common descent would be consistent with and provide strong support for universal common descent. (pp. 107-108)
Yet efforts to reconstruct phylogenetic trees using molecular or morphological traits frequently yield infamously inconsistent results. I’ve explained this numerous times, such as here, here, and here. Interestingly, Kuebler doesn’t dwell on the consistency of phylogenetic trees. Instead, he focuses on the existence of shared “synteny blocks.” Here’s what he says:
One particularly strong piece of evidence supporting this type of local common descent is the existence of homologous synteny blocks, which are similar regions of DNA that are conserved in different species. One can think of these synteny blocks as genome jigsaw puzzles that existed in a common ancestor but that are put together in different ways in their descendants due to various large-scale genome arrangements that have occurred over time.
To skip to the punchline, he says that
species as distantly related as humans and mice share a huge array of synteny blocks. Given that there seems to be no functional reason the genes found in these synteny blocks should be in a similar order in two distinct species (the likelihood of this happening by chance is vanishingly small), the most parsimonious explanation is that they were inherited in that specific order from a shared common ancestral species. (pp. 108-109)
Very Outdated Science
The problem with this argument is it’s based upon very outdated science. In fact, it’s shocking to me that a biologist in the 2020s would claim that there is “no functional reason” for the arrangement of genes on chromosomes. Much of what we have learned about genomics shows there are important reasons, core to genome function, for why chromosomes are structured the way they are. I explained here:
Synteny refers to large-scale similarities between genomes. [Some theistic evolutionists] argue that large-scale 3D features of the genome carry no functional significance. This is simply incorrect. Many papers show that the 3D large-scale organization of the genome is vital for genomic function. As the revolution in epigenetics has taken hold, molecular biologists now know that the structure of chromosomes, and their 3D arrangement(s) within a cell, are important parts of genomic regulation.
A variety of papers show that chromosomal structure and gene ordering can be functionally important — including the following:
- Jachowicz et al., “Heterochromatin establishment at pericentromeres depends on nuclear position,” Genes & Development, 27: 2427-2432 (2013);
- Verdaasdonk et al., “Centromere Tethering Confines Chromosome Domains,” Molecular Cell, 52: 1-13 (December 26, 2013);
- Filion et al., “Systematic Protein Location Mapping Reveals Five Principal Chromatin Types in Drosophila Cells,” Cell, 143: 212-224 (October 15, 2010);
- Giacomo Cavalli, “From Linear Genes to Epigenetic Inheritance of Three-dimensional Epigenomes,” Journal of Molecular Biology (2011);
- Justin M. O’Sullivan, “Chromosome Organizaton in Simple and Complex Unicellular Organisms,” Current Issues in Molecular Biology, 13: 37-42 (2011);
- Dirar Homouz and Andrzej S. Kudlicki, “The 3D Organization of the Yeast Genome Correlates with Co-Expression and Reflects Functional Relations between Genes,” PLoS One, 8: e54699 (January, 2013);
- Stephen A. Hoang and Stefan Bekiranov, “The Network Architecture of the Saccharomyces cerevisiae Genome,” PLoS One, 8: e81972 (December, 2013).
- Petkov PM, Graber JH, Churchill GA, DiPetrillo K, King BL, Paigen K. Evidence of a large-scale functional organization of mammalian chromosomes. PLoS Genet. 2005 Sep;1(3):e33.
- Graber JH, Churchill GA, Dipetrillo KJ, King BL, Petkov PM, Paigen K. Patterns and mechanisms of genome organization in the mouse. J Exp Zool A Comp Exp Biol. 2006 Sep 1;305(9):683-8.
- Spellman PT, Rubin GM. Evidence for large domains of similarly expressed genes in the Drosophila genome. J Biol. 2002;1(1):5. doi: 10.1186/1475-4924-1-5.
- Boutanaev AM, Kalmykova AI, Shevelyov YY, Nurminsky DI. Large clusters of co-expressed genes in the Drosophila genome. Nature. 2002 Dec 12;420(6916):666-9.
- de Wit E, Braunschweig U, Greil F, Bussemaker HJ, van Steensel B. Global chromatin domain organization of the Drosophila genome. PLoS Genet. 2008 Mar 28;4(3):e1000045. doi: 10.1371/journal.pgen.1000045.
Molecular biologists now know that the structure of chromosomes, and their three-dimensional arrangement(s) within a cell, are important parts of genomic regulation. The idea that “there seems to be no functional reason” for genes and chromosomes to be ordered and structured in particular ways is refuted by enormous numbers of discoveries we’re making in genomics.
One might be tempted to feel shocked that such strong evidence is essentially being ignored. Yet perhaps it’s not so shocking when one realizes that evolutionary arguments have a very long and sordid history of wrongly claiming that some feature isn’t functional, and that therefore it’s evidence for evolution.