Category: genetics

The Molecular Ecologist: I read A Troublesome Inheritance so you don’t have to

The Molecular Ecologist: I read A Troublesome Inheritance so you don’t have to

World Map - Abstract Acrylic
Image by Lara Mukahirn.

Over at The Molecular Ecologist I’ve done an in-depth review of the population genetics data cited by Nicholas Wade in his book A Troublesome Inheritance, which argues that social, cultural, and economic differences between human populations are all in our genes. Digging into the book’s endnotes, it didn’t take me long to find discrepancies between Wade’s description of basic population genetic results and the actual, um, results.

First and foremost, Wade claims that when population geneticists apply a class of statistical methods called clustering algorithms to datasets containing hundreds or thousands of genetic markers, they objectively identify five geographic groups that he calls “continental races”—differentiating African, European/Middle Eastern/South Asian, East Asian, Oceanian, and American people. What he does not make particularly clear is that while clustering methods do group genetic samples without direct instructions, the algorithms do not decide how many clusters there are. The geneticists using them do.

To make me feel somewhat better for having paid actual money to read this book, go read my whole review.◼
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The Molecular Ecologist: More functions, stronger selection?

The Molecular Ecologist: More functions, stronger selection?

Victorinox Swiss Army Knife

Photo by James Case.

Over at The Molecular Ecologist I’m discussing a new paper in the journal Genetics, which demonstrates that selection acts more strongly on genes that affect multiple traits:

Genes that have roles in multiple traits—pleiotropic genes—have long been thought to be under stronger selection as a result of those multiple functions. The basic logic is that, when a gene produces a protein that has a lot of different functional roles, there are more functions that will be disrupted by changes to that protein. Which would be more inconvenient: if your smartphone suddenly needed a new type of power connector, or if every electrical outlet in your house suddenly accepted only plugs with four prongs?

A team at the University of Queensland tested this idea using a lot of fruit flies and some cleverly applied gene expression resources. To find out how it all worked, go read the whole post, and check out the original paper.◼
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Nothing in Biology Makes Sense: Searching for Ronald Fisher

Nothing in Biology Makes Sense: Searching for Ronald Fisher

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Geneticist Ronald A. Fisher. Photo via WikiMedia Commons.

This week at the collaborative science blog Nothing in Biology Makes Sense!, my lab-mate John Stanton-Geddes writes about the current state of evolutionary genetics, as presented at the recent Evolution meetings in Ottawa:

One theme that emerged through the meeting was “The genetic basis for [insert trait here]. While this goal of mapping phenotype to genotype has been a primary goal of many evolutionary ecologists since the first QTL mapping studies, it has recently come under strong criticism, notably in a fantastic paper by Matthew Rockman in the journal Evolution last year, but also by Pritchard and Di Rienzo 2010 and in a forthcoming article by Ruth Shaw (full disclosure: Ruth was my PhD advisor) and Mike Travisano.

Readers of Denim and Tweed will recognize that John’s complaint about our ongoing fixation (ha!) on individual genes of large effect mirrors some of my own recent thinking. So naturally, I think you should go read the whole thing.◼


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