Thursday, October 06, 2011

Book Review - Relics of Eden

My birthday was this past Monday and as a present, I requested a Kindle. I got one, so immediately I looked over my reading list and started grabbing books.

The first one I picked up was Relics of Eden: The Powerful Evidence of Evolution in Human DNA by Daniel Fairbanks. I really liked the idea behind this book. After all, it's often been said that even completely ignoring the fossil record, homology, and every other field of biology, genetics would be suitable to establish evolution beyond a reasonable doubt. Yet books like Greatest Show on Earth don't give it much of a nod. The most we're treated to is the evolutionary requirement that chromosome 2 in humans have been the result of fusion from an ancestral species.

Relics of Eden takes this same idea, but provides numerous more examples. The first chapter goes through the chromosome 2 fusion. The second, examines Barbara McClintock's study of corn which led to the discovery of transposons. When these were analyzed, they showed the same sort of divergence in humans and our closely related cousins as evolution would predict.

The third chapter is about "Bogus Genes" which are often duplicated genes that have been disabled by mutations. One of the lessons here is that evolution predicts that, since these pseudogenes aren't being selected for, they should have accumulated more mutations. This evolutionary prediction, as Fairbanks points out, is confirmed. This chapter also discusses the GLUO pseudogene which is disabled in humans and, in other species, serves to produce vitamin C. The function of this gene wouldn't likely be selected for since humans had a wealth of vitamin C in their diet and as such, the presence of this gene is much like a vestigial organ. Another gene, glucocere-brosidase gene (GBA), is repeated but one copy also shows a deletion of 55 base pairs in humans, chips, and gorillas, but not in orangutans have both functioning, and squirrel monkeys only have a single gene. Such patterns make sense in the light of evolution: The duplication happened after the divergence from the line that would lead to squirrel moneys, and the deletion happened after the speciation in which orangutans broke off. Another example of this listed is the cytochrome c pseudogene family which shows a similar pattern and confirms the divergences.

The fourth chapter is trying to figure out exactly when humans, chips, and gorillas split apart, or which one did first, a problem the author calls the "trichotomy problem". The answer can be found in mitochondrial DNA which reveals gorillas split off first. This can be independently checked using nuclear DNA.

Chapter 5 looks at more connections to selection effects in genetics. Like with pseudogenes, mutations tend to accumulate more in exons which aren't selected for. The chapter also explores the NANOG gene which can also be used to look for patterns of divergence.

Chapter 6 is about the inversions in genes between chimps and humans how evolution can explain these.

The last chapter that's really about evidence for evolution is chapter 7 which looks at diversity. Specifically looked at the dispersion of genes in humans alone, tracing specific genes (such as descendants of Gengis Khan) as they spread as well as looking at the origin of humans in sub-Saharan Africa.

Chapter 8 was a look at what evolution is. It's mostly a look at how scientists define it today with some historical nods to Darwin and a few mentions of some of the non-genetic evolutionary evidences (such as the development of whales and dolphins). It also has a bit on how genetics can be used to construct phylogenetic trees.

The 9th chapter is "When faith and reason clash". It is an abbreviated history of Intelligent Design and Creationism which is so brief, it fails to draw some important distinctions, like the direct development of ID from Creationism. The author treats them as independent and that simply ain't so.

The final chapter is on breaking down the divide between science and faith. In my opinion, it should simply be tossed out. It's accommodationist noise. It says nothing more than "Some people can compartmentalize." Yet it fails to address the frequent fallacies committed by those that do (such as Ken Miller).

After this "last chapter", you're still actually only half way through the book. There's 3 appendices. The first two are more evidences that are even more technical. The first looks more in depth at the NANOG gene previously mentioned. The second is more on the inversions in genes discussed earlier as well. The final one is a short history of Genetics.

So what's my overall feeling of the book? It has a ton of great information. However, it was poorly organized. It seemed to toss most of the information first, and then organize it later, after most readers would likely be confused at the significance. I think the writing could have been greatly improved by essentially reversing the book (appendices included), teaching more about the history of evolution and genetics, then looking at how the evidence fit those predictions. I also think that the way the evidence was presented could have been much stronger. It should be made much clearer that every way these evolutionary trees are constructed, no matter which gene, pseudogene, chromosomal reversal, or other genetic bit mentioned, they always come out the same and provide independent evidence. While it's hinted at weakly, it's never directly compared to the parsimony of a designer independently making all these changes in order to fool us. I've seen that argument presented elsewhere, and it's devastating to ID/Creationism. Yet the author sidesteps it.

Another note is that this book is rather technical. While the terms are defined, they are then immediately used heavily and readers are expected to keep up. Having done a great deal of reading on evolution over the past decade, and teaching a bio course, I followed along without too many problems, but an inexperienced reader would likely struggle. The introduction to terms could be improved as well as the usage when terms are required later.

So in closing, not bad, but needs an overhaul in the organization for the average reader.

1 comment:

jedtew said...

I presume you meant "chimps", not "chips".