Evolution and homosexuality

Seed has an interview with Joan Roughgarden, somewhat controversial evolutionary biologist and author of Evolution’s Rainbow : Diversity, Gender, and Sexuality in Nature and People(amzn/b&n/abe/pwll). Here’s the short summary of her basic thesis:

Joan Roughgarden thinks Charles Darwin made a terrible mistake. Not about natural selection–she’s no bible-toting creationist—but about his other great theory of evolution: sexual selection. According to Roughgarden, sexual selection can’t explain the homosexuality that’s been documented in over 450 different vertebrate species. This means that same-sex sexuality—long disparaged as a quirk of human culture—is a normal, and probably necessary, fact of life. By neglecting all those gay animals, she says, Darwin misunderstood the basic nature of heterosexuality.

Roughgarden is an awkward case that provokes a difficult split in people’s opinions. She is 100% right that homosexuality is common and that its prevalence ought to be regarded more seriously as an indication of an interesting and enlightening phenomenon in evolution. However, she’s completely wrong in rejecting sexual selection: in rejecting a simplistically heterosexual view of nature she swings too far the other way, adopting a simplistically homosexual view instead of a messy, complex, and almost certainly more correct mixed view. She’s rather superficial in her treatment of Darwin. And most annoyingly, she has a bad habit of playing the transgender card and accusing her critics of disagreeing with her because of some LGBT bias.

[Read more…]

Clausen, Keck, Hiesey

i-ccbc028bf567ec6e49f3b515a2c4c149-old_pharyngula.gif

To continue a bit of theme, I mentioned that there were some different ways to approach biology, and that old-school systematists with their breadth of knowledge about the diversity of life are getting harder and harder to find. This is something I also bring up in my introductory biology course, where we discuss how biologists do their work, and I mention that one distinction you can find (which is really a continuum and frequently breached) is that there are bench scientists and field scientists, and they differ in multiple ways. Bench scientists tend to be strongly reductionist, tend to focus on one or very few species, and may study just one specific, highly inbred lab strain of a species, and try to minimize environmental variables. Variation is noise that interferes with getting at basic mechanisms. Field scientists, on the other hand, argue that the simplicity of the lab is unrealistic, that the proper study of organisms has to be done in the messy complexity of the real world, and think that variation, rather than being uninteresting noise, is fascinating stuff, the meat and potatoes of evolution. Both points of view have their place, and speaking for all biologists, I think we appreciate the power and necessity of both approaches. The money seems to mostly go to the bench guys, though, which does unfortunately skew the field as a whole.

[Read more…]

Penis evolution

i-ccbc028bf567ec6e49f3b515a2c4c149-old_pharyngula.gif

After the recent struggles trying to keep up with the traffic on this site, you wouldn’t think I’d feel compelled to go trolling for more visitors, but isn’t that the nature of weblogging? The only point to it all is to rack up a bigger score than the next guy, as if we were playing pinball. So what’s a good ploy? As Lauren has cleverly pointed out, sex sells. And while it may be estrogen week, I’m going to buck the trend, since we all know what’s really important for weblog popularity: penises.

[Read more…]

Pufferfish and ancestral genomes

i-ccbc028bf567ec6e49f3b515a2c4c149-old_pharyngula.gif

i-ee5df192ed46616d0681fb8208d124f6-greenspottedpuffer.jpg

The fugu is a famous fish, at least as a Japanese sushi dish containing a potentially lethal neurotoxin that was featured on an episode of The Simpsons. Fugu is a member of the pufferfish group, which have another claim to fame: an extremely small genome, roughly a tenth the size of that of other vertebrates. The genome of several species of pufferfish is being sequenced, and the latest issue of Nature announces the completion of a draft sequence for the green spotted pufferfish, Tetraodon nigroviridis, a small freshwater species.

[Read more…]

How to evolve a vulva

i-ccbc028bf567ec6e49f3b515a2c4c149-old_pharyngula.gif

Creationists are fond of the “it can’t happen” argument: they like to point to things like the complexity of the eye or intricate cell lineages and invent bogus rules like “irreducible complexity” so they can claim evolution is impossible. In particular, it’s easy for them to take any single organism in isolation and go oooh, aaah over its elaborate detail, and then segue into the argument from personal incredulity.

[Read more…]

Modules and the promise of the evo-devo research program

Since Evolgen recognizes the importance of evo-devo, I’ll return the favor: bioinformatics is going to be critical to the evo-devo research program, which to date has emphasized the “devo” part with much work on model systems, but is going to put increasing demands on comparative molecular information from genomics and bioinformatics to fulfill the promise of the “evo” part. I’m sitting on a plane flying east, and to pass the time I’ve been reading a very nice review of the concept of modularity in evo-devo by Paula Mabee (also a fish developmental biologist, and also working in a small college in a small town in the midwest…but rather deservedly better known than yours truly). In addition to summarizing the importance of the concept of modularity to evolution and development, the paper also does something I always appreciate: it summarizes the key questions that the modern evo-devo research program is working to answer.

[Read more…]

Evo-devo wars

Fellow scienceblogger Evolgen has seen the light—evo-devo is wonderful. He’s attending a meeting and listening to some of the bigwigs in the field talk about their work, in particular some research on the evolution of gene regulation. While noting that this is clearly important stuff, he also mentions some of the bickering going on about the relative importance of changes in cis regulatory elements (CREs) vs. trans acting elements, transcription factors. I’ve got a longer write-up of the subject, but if you don’t want to read all of that, the issue is about where the cool stuff in the evolution of morphology is going on. Transcription factors are gene products that bind to regulatory regions of other genes, and change their pattern of expression. The things they bind to are the CREs, which are non-coding regions of DNA associated with particular genes.

[Read more…]

Chelifores, chelicerae, and invertebrate evolution

i-10737b7f756345115b363532bc4759a5-pycno_anomalo.gif

One of the most evocative creatures of the Cambrian is Anomalocaris, an arthropod with a pair of prominent, articulated appendages at the front of its head. Those things are called great appendages, and they were thought to be unique to certain groups of arthropods that are now extinct. A while back, I reported on a study of pycnogonids, the sea spiders, that appeared to show that that might not be the case: on the basis of neural organization and innervation, that study showed that the way pycnogonid chelifores (a pair of large, fang-like structures at the front of the head) were innervated suggested that they were homologous to great appendages. I thought that was pretty darned cool; a relic of a grand Cambrian clade was swimming around in our modern oceans.

However, a new report by Jager et al. suggests that that interpretation may be flawed, and that sea spider chelifores are actually homologous to the chelicerae of spiders.

[Read more…]

No genes were lost in the making of this whale

i-ae96b1925d274fb6e2cec2bef0131fe7-cet_dolphin_tease.gif

I just learned (via John Lynch) about a paper on cetacean limbs that combines developmental biology and paleontology, and makes a lovely argument about the mechanisms behind the evolution of whale morphology. It is an analysis of the molecular determinants of limb formation in modern dolphins, coupled to a comparison of fossil whale limbs, and a reasonable inference about the pattern of change that was responsible for their evolution.

One important point I’d like to make is that even though what we see in the morphology is a pattern of loss—whale hindlimbs show a historical progression over tens of millions of years of steady loss, followed by a near-complete disappearance—the molecular story is very different. The main players in limb formation, the genes Sonic hedgehog (Shh), the Fgfs, and the transcription factor Hand2, are all still present and fully functional in these animals. What has happened, though, is that there have been novel changes to their regulation. Even loss of structures is a consequence of changes and additions to regulatory pathways.

[Read more…]