The Pharyngula Mutating Genre Meme

I confess, I like this blog meme. I studied how mutations happen in bacteria in graduate school, so anything even tangentially related to that has my interest. This blog meme was created by Pharyngula as a means of demonstrating evolution and mutation in cyberspace:

There are a set of questions below that are all of the form, "The best [subgenre] [medium] in [genre] is...". Copy the questions, and before answering them, you may modify them in a limited way, carrying out no more than two of these operations:

* You can leave them exactly as is.

* You can delete any one question.

* You can mutate either the genre, medium, or subgenre of any one question. For instance, you could change "The best time travel novel in SF/Fantasy is..." to "The best time travel novel in Westerns is...", or "The best time travel movie in SF/Fantasy is...", or "The best romance novel in SF/Fantasy is...".

* You can add a completely new question of your choice to the end of the list, as long as it is still in the form "The best [subgenre] [medium] in [genre] is...".

* You must have at least one question in your set, or you've gone extinct, and you must be able to answer it yourself, or you're not viable.

Then answer your possibly mutant set of questions. Please do include a link back to the blog you got them from, to simplify tracing the ancestry, and include these instructions.

Finally, pass it along to any number of your fellow bloggers. Remember, though, your success as a Darwinian replicator is going to be measured by the propagation of your variants, which is going to be a function of both the interest your well-honed questions generate and the number of successful attempts at reproducing them.

My great-great-great-grandparent is Pharyngula
My great-great-grandparent is Metamagician and the Hellfire Club
My great-grandparent is Flying Trilobite
My grandparent is A Blog Around the Clock
My parent is The Primate Diaries

The best time travel novel in SF/fantasy is:

Slaughterhouse Five by Kurt Vonnegut

The best scary movie in scientific dystopias is:

Alien

The best sexy song in electronica is:

"The Sea" by Morcheeba.

The best page-turner book in Nobel-prize-winning fiction is:

"Blindness" by Jose Saramago

I am propagating this meme on to:

ERV
Denialism
Bug Girl
White Coat Underground
Bronze Blog
Skeptical Alchemist

It'll be interesting to see how this experiment ends up. Don't let it go extinct!

On the cause of autism.

A new Nature Medicine (subscription requried) "News & Views" article by Art Beaudet at Baylor College of Medicine summarizes some new discoveries about autism. As it turns out, somewhere between 10-30% of autism patients can be demonstrated to have de novo mutations (i.e. occurring in the sperm or egg) that cause their symptoms. This is cool work, as two different groups found copy number changes in 10-30% of autism patients that wasn't present in the parents. Why is this cool? Because it answers a longstanding question:

Autism is thought to be highly heritable, largely because of a very high concordance in monozygous (identical) twins—although the concordance in dizygous (fraternal) twins is low.

One would expect the frequency to be lower in fraternal twins, but for autistic patients, this was lower than normal. Well:

All of the genetic abnormalities discussed here would be expected to be associated with virtually 100% concordance in monozygotic twins and, for the de novo majority, very low concordance in dizygotic twins ... ... Thus, for a fraction of cases, this new understanding of the genetic etiology of autism fits perfectly with the previously puzzling data from twins.

So, if many of the changes are mutations occurring in the sperm or eggs, one would expect identical twins to have the same disease, as they would both carry the mutation. But the odds of both fraternal twins getting sperm or eggs that carry a brand new mutation are astronomical.

Beaudet hypothesizes two things:

Higher density arrays focused at the level of single exons are likely to be very productive in identifying smaller abnormalities that may be immediately traceable to specific genes.

That is, once we look more closely, it may turn out that an even higher percentage of autism patients are due to de novo mutations. And second:

Our view is that epigenetic abnormalities of chromatin that are not associated with nucleotide sequence changes might contribute to the etiology in this group; particularly given the male predominance, epigenetic abnormalities affecting the X or Y chromosome might be hypothesized. We have proposed a mixed epigenetic and genetic and mixed de novo and inherited model for autism, in which individual patients could have a genetic (mutation) or epigenetic (epimutation) etiology and these components could be inherited in some cases and de novo in others.

He suggests that epigenetic factors will prove to be important for other patients, that is that improper modification of chromosomes in the mother or father, will be the causative agent. Though to be fair, he says:

an epigenetic component, if one exists, remains elusive

Nonetheless, we are now discovering the cause of autism in some patients. Now, some important questions remain. Are the sites that are mutating de novo particularly susceptible to mutation? Or are other sites that mutate just less important? And importantly, what do these sites tell us about the pathology of autism? And can we design treatments and diagnostic tests to find and help autism patients? Can we find the cause of autism in other autistic patients?

This paper raises the possibility that we could know the causes of all autism in the near future. Very exciting, indeed!