Imagine my surprise when Sternberg responded with a "correction"! [Let's Do the Math Again].
Earlier today I criticized Calvin College biologist Steve Matheson’s incorrect view of “junk” DNA. Matheson had argued in February that the human genome contains about 190,000 introns (stretches of non-protein-coding DNA that interrupt protein-coding genes), of which “only a handful” had important functional roles. “How many? Oh, probably a dozen,” he wrote, “but let's be really generous. Let's say that a hundred introns in the human genome are known to have ‘important functional roles.’ Oh fine, let's make it a thousand.”A few minor corrections ...
On the contrary, I pointed out that at least 90% of genes are alternatively spliced, meaning that 0.9 x 190,000 = 171,000 introns are involved in alternative splicing, an essential process that helps to ensure that the proper proteins are made at the correct developmental stage and in the appropriate cells and tissues.
Along comes University of Toronto biochemist Larry Moran, an outspoken Darwinist who hates the Center for Science and Culture so much he would probably heap abuse on us for saying that the Earth goes around the Sun. Sure enough, Moran wasted no time jumping on me for being an “Intelligent Design Creationist.” He posted the relevant portion of my critique and concluded: “It's up to you, dear readers, to figure out all the things wrong with this explanation. You can start with the math. Arithmetic isn't one of their strong points.”
- I am not a Darwinist [Why I'm Not a Darwinist]
- I don't hate the Center for Science and Culture. I mock it. It's a joke.
- Richard Sternberg supports intelligent design and be believes in a creator who used intelligent design to create life. Therefore, he is an Intelligent Design Creationist.
So let’s do the math. Again. I will make the task easy for everyone—even Moran and Matheson:I'm using arithmetic that's based on an understanding of basic molecular biology and the scientific literature.
Step 1. There are ~25,000 protein-coding genes in the human genome.
Step 2. There are 190,000 introns/25,000 protein-coding genes = 7.6 introns/gene on average.
Step 3. Ninety percent (possibly more) of gene transcripts undergo alternative splicing. Hence, 0.9 x 25,000 = 22,500 genes (actually, their RNAs) undergo alternative splicing.
Therefore, 22,500 genes x 7.6 introns/gene = 171,000 introns involved in alternative splicing.
This is just a rough estimate, of course. And as I wrote in my original critique of Matheson, even if I’m off by a factor of two we are still left with far more functional introns than Matheson acknowledges. This compels me to ask Steve Matheson: How exactly did you come up with your estimates? And what about you, Larry Moran? What sort of arithmetic are you using?
We could quibble about the number of introns—I think it's closer to 150,000. We could quibble about the number of protein encoding genes—the most accurate number is 20,500. We could quibble about how many genes exhibit alternative splicing—I think it's about 5%, not 95%. You can't be expected to know the facts and the controversies since this is way outside your area of expertise.
So, let's assume your facts are correct. If 90% of genes exhibit alternative splicing then this means 22,500 genes. You got that calculation right. The minimum number of introns that must be involved in alternative splicing is one (1) per gene. That means at least 22,500 introns involved in alternative splicing. You made the mistaken (and stupid) assumption that every intron in a gene had to be alternatively spliced.
The fact that you repeated this false assumption, even after being warned, does not enhance your credibility. I conclude that you don't understand RNA processing or alternative splicing. In spite of your ignorance you wrote up a posting attacking Steve Matheson and defending your colleague Steve Meyer. That's why we call you IDiots.