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Latest in a series of wacky discussions of genome size by physicists, CLASSIFICATION OF LIFE BY THE MECHANISM OF GENOME SIZE EVOLUTION DIRSON JIAN LI, SHENGLI ZHANG We find that the global relationships among species should be of circular phylogeny, which is quite different from common sense based on phylogenetic trees. A domain [...] I sometimes get asked if non-coding elements (usually “junk DNA” is what they say) can ever evolve into genes. I usually say that transposable elements, at least, can be coopted into functional roles, and that it wouldn’t be so odd if a pseudogene took on a novel function sometime through mutations. Kind of a [...] Ok, check this out! Seemingly misplaced DNA acts as lenses Reporting on Solovei et al (2009) We show that the nuclear architecture of rod photoreceptor cells differs fundamentally in nocturnal and diurnal mammals. The rods of diurnal retinas possess the conventional architecture found in nearly all eukaryotic cells, with most heterochromatin situated at the [...] This appeared in my weekly automated journal search. I have ordered the paper as I can’t find an online copy, but the abstract pretty much covers what the argument will be. Same old pre-1980s adaptationist idea presented as radically novel. Mallik, M. and Lakhotia, S.C. 2008. Noncoding DNA is not “junk” but a necessity [...] Just for fun, here are some quotes I came across while reading a few sources for a paper I am writing. Remember, a significant number of creationists, science writers, and molecular biologists want us to believe that non-coding DNA was totally ignored after the term “junk DNA” was published in 1972, that the [...] We have been told in science news stories since the early 1990s that biologists long neglected the potential significance of noncoding DNA. (Sadly, this is in line with the claims made by creationists, who claim that “Darwinism” is to blame despite the obvious fact that Darwinian adaptationism would expect functions. Some biologists likewise play [...] Each copy of the human genome consists of about 3,200,000,000 base pairs, and includes about 500,000 repeats of the LINE-1 transposable element (a LINE) and twice as many copies of Alu (a SINE), as compared to around 20,000 protein-coding genes. Whereas protein-coding regions represent about 1.5% of the genome, about half is made up [...] In this post, I will maintain an up to date list of substantive posts dealing with the topic of “junk DNA” on this blog and various others. Genomicron Junk DNA – the quotes of interest series Non-functional DNA: the burden of proof Non-functional DNA: quantity Non-functional DNA: non-functional vs. inconsequential MASHing junk DNA Function, [...] In my previous post, I noted that because of what we understand about the nature, origins, and cross-taxon quantitative diversity of the various sorts of non-genic DNA in large eukaryote genomes, the default assumption is that much or even most of it is not functional at the cell and organism levels. Thus, the burden [...] |
T. Ryan Gregory 
I am an evolutionary biologist specializing in genome size evolution at the University of Guelph in Canada.
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