Junk DNA: goodbye!: A new book (Introduction)

by David Turell , Thursday, April 30, 2015, 02:08 (3496 days ago) @ David Turell

Another review, in great detail, of Nessa Carry's book, Junk DNA. She thinks many more functions will be found:-http://www.evolutionnews.org/2015/04/a_new_book_on_j095611.html-"The other shock from the sequencing of the human genome was the realisation that the extraordinary complexities of human anatomy, physiology, intelligence and behaviour cannot be explained by referring to the classical model of genes. In terms of numbers of genes that code for proteins, humans contain pretty much the same quantity (around 20,000) as simple microscopic worms. Even more remarkably, most of the genes in the worms have directly equivalent genes in humans.-"As researchers deepened their analyses of what differentiates humans from other organisms at the DNA level, it became apparent that genes could not provide the explanation. In fact, only one genetic factor generally scaled with complexity. The only genomic features that increased in number as animals became more complicated were the regions of junk DNA. The more sophisticated an organism, the higher the percentage of junk DNA it contains. Only now are scientists really exploring the controversial idea that junk DNA may hold the key to evolutionary complexity. (p. 4)-"Carey doesn't openly take a side in the debate over ENCODE, and she doesn't claim that our genome will eventually turn out to contain no "junk" DNA whatsoever. But she is clear that the trend line in research is away from junk DNA, and she notes that one reason for our lack of understanding of what a lot of junk DNA does is that we haven't yet developed the technologies to study it:-"Part of the problem is that the systems we can use to probe the functions of junk DNA are still relatively underdeveloped. This can sometimes make it hard for researchers to use experimental approaches to test their hypotheses. We have only been working on this for a relatively short space of time. (p. 6)
of the important functions going on in the genome. -"As Carey notes, "We now know that in some cases just a single base-pair change in an apparently irrelevant region of the genome can have a definite effect" (p. 201), meaning there's a lot of work left to be done. After all, she points out: "One stretch of DNA can include a protein-coding gene, long non-coding RNAs, small RNAs, antisense RNAs, splice signal sites, untranslated regions, promoters and enhancers." (p. 287) Thus, she concludes, "When we really think about the complexity of our genomes, it isn't surprising that we can't understand everything yet." (p. 288) And that, along with much else in this excellent book, hits the nail on the head."