Laurence A Moran - new book on junk DNA

[ho_idiotes (Matt)]

Do you see that as an argument against the notion that the junk DNA actually acts as a buffer against negative mutations? I think that is something I heard somewhere with examples like you have as a counter

[ho_idiotes (Matt)]

I am listening to the following book when I am doing other things. Some good content on junk DNA here as well
Herding Hemmingways Cats - Understanding How our Genes Work by Kat Arney

[T_aquaticus]

@ho_idiotes

Do you see that as an argument against the notion that the junk DNA actually acts as a buffer against negative mutations?

I don’t see how this would be the case. You get the same number of mutations in functional DNA no matter how much junk DNA there is. The mutation rate is a per base rate, so the less DNA you have the fewer mutations you get.

[ho_idiotes (Matt)]

Zach B Hancock has just uploaded a video on this also

Jeff's Genomic Junk

[ho_idiotes (Matt)]

@T_aquaticus

I don’t see how this would be the case. You get the same number of mutations in functional DNA no matter how much junk DNA there is. The mutation rate is a per base rate, so the less DNA you have the fewer mutations you get.

I found the section in Moran’s book dealing with it (pg 107) - he calls it the bodyguard hypothesis. Apparently it is an argument by someone called Nessa Carey, and also Claudiu Bandea. I had heard it referenced somewhere else. Both Moran and the other source I can’t remember basically said the same as you.

@John_Harshman

Different sort of test. The onion test doesn’t compare an onion genome to a human genome. It compares the genomes of two species of onion, one of which is twice the size of the other one. It asks why two species with nearly identical phenotypes need such radically different amounts of DNA. Hey, maybe a lot of it is junk

Moran seems to think it is both the comparison to the human genome as well as other onion species (pg 109 ish). Am I misunderstanding him?

As if this weren’t enough, none of these bodyguard ideas passes the Onion Test. If protecting DNA is so important, then how can it explain the fact that the onion needs so much more protection than humans and that different onion species have quite different amounts of insulating DNA?

[John_Harshman]

@ho_idiotes

Am I misunderstanding him?

Looking at an approximation of the original post by T. Ryan Gregory (the real original is no longer available), I see I was wrong. The onion test involved comparisons with humans and with other onions.

Junk DNA And The Onion Test

There are many other potential tests, such as the fugu test or the Arabidopsis test. More broadly, the so-called C-value paradox.

[T_aquaticus]

This chart is worth digitally earmarking. Genome size is measured in mass:

Chapter 2: The Evolution of Sloppy Genomes

[John_Harshman]

If I recall, 1 picogram is approximately 1 billion base pairs.