'Genome' is now a pretty standard word in our social vocabulary.

Genetic hitchhiking is thought to be an inevitable result of strong positive selection in a population. The basic idea is that if a particular gene is strongly selected for (as opposed to selected against), then the chunk of the genome that carries that gene will become very common in the population.

The next post will discuss recent evidence for genetic hitchhiking in humans. So, what do we mean when we say that genes can hitchhike? To make sense of this phenomenon, we first need to review chromosomes and sexual reproduction. Most people know that sexual reproduction creates offspring that are genetically distinct from both of the their parents.

Age-related macular degeneration (AMD) is a leading cause of blindness in humans, and the leading cause of visual impairment during advanced age. The condition comes in two basic forms, the most severe of which is untreatable.

Defenders of intelligent design theory often dwell on the topic of "junk DNA," which has been molded into a masterpiece of folk science. The ID approach to "junk DNA" involves a fictional story about "Darwinism" discouraging its study, and a contorted and simplistic picture of a "debate" about whether "junk DNA" has "function." The fictional story is ubiquitous despite being repeatedly debunked.

So why is it that I and many other biologists hypothesize that introns are mostly non-functional? (I'll assume that you've read the previous posts, and that you understand what it is that I mean when I challenge claims that introns are functional elements in an information-rich genome.

What does it mean to claim that an intron has a function? The question is obviously important, at least as long as there are disputes about whether introns have "functions" and whether science ignored them for decades. Now, I can't help the ID people with their propensity for repeating falsehoods about the history of "junk DNA" and the role of "Darwinism" in its characterization.

Before we explore what introns are and how they work, let me correct the misuse of my words by one of the ID attack kittens. Months ago, referring to Steve Meyer's claim that introns "are now known to play many important functional roles in the cell," I sought to put intron "function" into context as follows: One critic has interpreted me as claiming that I know that 189,000 introns have no function.

No one should take advice from this character, I'll grant you.

Almost two years ago, I reviewed Michael Behe's latest book, The Edge of Evolution, here on the blog. I was unimpressed, to say the least, and remain of the opinion that Behe should not be considered a serious scientific thinker given his failure in that ludicrous book.