Casey Luskin on Junk DNA and Junk RNA

 
Intelligent Design Creationists can't abide junk DNA. Its very existence refutes the idea that living things are designed by some intelligent being. This is why the IDiots go out of their way to make up stories "disproving" junk DNA.

The latest attempt is by Casey Luskin [Nature Paper Shows "Junk-RNA" Going the Same Direction as "Junk-DNA"]. Having failed to explain why half of the human genome is composed of defective transposons, he now pins his hope on the idea that most of the genome is transcribed. Luskin seems particularly upset by my statement that most of these transcripts are junk [Junk RNA].

Luskin thinks that a recent paper in Nature supports his view that a large fraction of the genome isn't junk. The paper by Guttman et al. (2009) says no such thing. Here's the important part ...

Genomic projects over the past decade have used shotgun sequencing and microarray hybridization1, 2, 3, 4 to obtain evidence for many thousands of additional non-coding transcripts in mammals. Although the number of transcripts has grown, so too have the doubts as to whether most are biologically functional5, 6, 13. The main concern was raised by the observation that most of the intergenic transcripts show little to no evolutionary conservation5, 13. Strictly speaking, the absence of evolutionary conservation cannot prove the absence of function. But, the markedly low rate of conservation seen in the current catalogues of large non-coding transcripts (<5% of cases) is unprecedented and would require that each mammalian clade evolves its own distinct repertoire of non-coding transcripts. Instead, the data suggest that the current catalogues may consist largely of transcriptional noise, with a minority of bona fide functional lincRNAs hidden amid this background. Thus, to expand our understanding of functional lincRNAs, we are faced with two important challenges: (1) identifying lincRNAs that are most likely to be functional; and (2) inferring putative functions for these lincRNAs that can be tested in hypothesis-driven experiments.

In other words, most of the transcripts are probably transcriptional noise, or junk, just as I said. This is the consensus opinion among informed¹ molecular biologists.

Guttman et al. wanted to identify the small subset that might be functional. They identified 1,675 transcripts that show evidence of conservation. The average transcript has six exons averaging 250 bp. Thus, each transcript has about 1500 bp. of conserved exon sequence.

Even if every single one of these lincRNAs have a biological function they will only account for 1675 × 1500 = 2.5 million bp. This represents less than 0.1% of the genome. Casey Luskin ain't gonna disprove junk DNA using this paper.

Luskin ends his article with ...

As an ID proponent, I'm still waiting for Darwinists to let go of their precious "junk" arguments for blind evolution and common descent and learn the lesson that you can't assume that if we don't yet see function for a biomolecule, then it's probably just "junk."

This is a point of view that creationists share with many scientists who haven't studied the subject. They assume that the only reason for labeling most of our DNA junk is because we don't know what it does. That's just not true. There's plenty of good evidence that most of our genome can't be functional. We know a lot about the part that consists of transposons and defective transposons, for example [Junk in Your Genome: SINES and Junk in your Genome: LINEs]. That's 44% of our genome.

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1. I added the qualifier "informed" after a commenter pointed out that most molecular biologists probably don't know enough about the topic to have an opinion. Thus, according to this commenter, the consensus opinion would be "I don't know."