Science online, the nights after Christmas edition

Vintage Romance Novels Romance novels are totally evidence of sexual conflict in humans, you guys. Photo by Stewf.

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Have yourself a scientific Christmas

The love makes beautiful. frosted landscape for christmas xmas and happy new year pour noël et le nouvel an Photo by Thierry.

Have yourself a scientific Christmas,
May your teaching load be light!
Next year maybe funding will not be so tight.
Have yourself a scientific Christmas,
Pipette your last lane …
Don’t stir the reagents with that candy cane!

You’re done with your holiday shopping and ready to read about selective breeding of Christmas trees, right? Well, then the Molecular Ecologist has just the post for you. Or maybe you’d rather check out an old Denim and Tweed post about mistletoe population genetics?

And a happy midwinter celebration of your choice to all!◼

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Science online, apocalypse not yet edition

Northern Pronghorn Antelope Photo by Dan W Conway.

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The Molecular Ecologist: Sexual selection, natural selection, and pronghorn

Run antelope, run! Male pronghorn, on the run. Photo by Great Beyond.

Meanwhile, over at The Molecular Ecologist, I interviewed my old friend Stacey Dunn about a study of hers recently published in Science, which presents ten years of data to examine how A.J. Bateman’s principal of sexual selection — that males maximize their evolutionary fitness by mating with lots of females, but females maximize their fitness by mating with just one or a few carefully-chosen males — in pronghorn.

The National Bison Range pronghorn have been studied extensively by John [Byers] and his lab since 1981. Each spring, we captured nearly all fawns born in the population. During captures, we weighed, measured, sexed and tagged the fawns and took a tissue sample for genetic analysis. We genotyped each individual alive since 1999 at 19 microsatellite loci. We determined paternity for all fawns based on genotype. Maternity was known from fawn captures, but was also confirmed genetically. We then used that information to reconstruct a multi-generational pedigree of the pronghorn population.

To learn how the study improves on Bateman’s original work with fruit flies (which has since been called into question for methodological issues), and for Stacey’s tips on how to catch a baby pronghorn, go read the whole thing.◼

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Nothing in Biology Makes Sense: Making sense of same-sex orientation in humans

This week over at Nothing in Biology Makes Sense, I’m taking a look at a much-heralded new journal article that purports to solve an evolutionary puzzle that has particularly personal interest to me: how same-sex sexual orientation could evolve in the face of its selective costs. Of course, I’ve previously discussed a long list of possible answers to this question — but the new paper suggests that the best solution may lie in the epigenetics of sexual development.

Epigenetics is an appealing explanation for same-sex attraction because we have, at best, a fuzzy picture of the genetic basis of sexual orientation. Homosexuality definitely “runs in families”. That is, people with gay or lesbian parents, siblings, aunts, or uncles are more likely to be gay or lesbian themselves; and pairs of identical twins, who share pretty much all their genetic code, are more likely to have the same sexual orientation than pairs of fraternal twins, who share only half their genes.

Yet more sophisticated methods to identify specific genes associated with sexual orientation have failed to find any consistent candidates. (Though, as a caveat, the only genetic association study [PDF] I’ve seen suffers from small sample size and considers a very small number of markers by modern standards.) Moreover, while identical twins share sexual orientation more than fraternal twins, they don’t share it with complete fidelity — only about 20% of gay men who are identical twins have twin brothers with the same orientation.

For an explanation of what exactly epigenetics is, a full description of the new study, my evaluation of it all, and even some gratuitous — if, I hope, educational — beefcake, you’ll have to go read the whole thing.◼

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Science online, field of monocultures edition

cornfield Photo by Jvstin.
  • This week at Nothing in Biology Makes Sense! Devin Drown reviews The Adaptive Landscape in Evolutionary Biology.
  • And at the Molecular Ecologist: The carnival of knowing what I know now.
  • Surprise? The biodiversity of a cornfield is pretty depressing.
  • Handy. Tinkering with fishes’ developmental genes recreates (a bit) of the evolution of fins into digits.
  • Of course, winter means wearing more clothes, which harbor lice … Napoleon’s invasion of Russia was stymied not by winter, but by lice carrying typhus.
  • It is, as they say, all in your head. The physical reality underlying near-death experiences.
  • A mess, but one we need to clean up. Race, poverty, and access to education.
  • Inactivated what now? A new therapy for leukemia that uses inactivated HIV to reprogram white blood cells looks promising.
  • For all the good that will do. Climate scientists are starting to use alarming talk titles at conferences.
  • A crucial question. How well would wine grapes really grow in world of Game of Thrones?

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The living rainbow: Er, kinda …

06 Drosophila melanogater Mating Mating fruit flies. Photo by Image Editor.

I just saw this from Christopher Ryan, coauthor of Sex at Dawn, on Twitter:

Foundational Evolutionary Psychology paper called into serious question. Randy males/choosy females? Maybe not. npr.org/blogs/13.7/201…

— Christopher Ryan (@ChrisRyanPhD) December 13, 2012

As I tweeted in response: er, kinda.

Ryan linked to some new discussion of a study I covered back in June. That paper found a major flaw in a 1948 study of Drosophila fruit flies that was the first to clearly support a component of sexual selection theory — the idea that males maximize their evolutionary fitness (i.e., the number of offspring they sire) by having many mates, but females maximize fitness by selecting just a single “best” mate.

The author of the 1948 study, A.J. Bateman, tracked the parentage of flies in his study — which was necessary to tally the offspring of each male and female fly — using visible “marker” mutations. The new study’s authors, Patricia Gowaty et al., tried to replicate Bateman’s experiment, and discovered that some of the marker mutations were so disabling to the flies that they almost certainly biased Bateman’s results.

That knocks the legs out from under Bateman’s experiment. But it doesn’t really deal a knockout punch to sexual selection, much less to evolutionary psychology. Yes, evo psych (especially the kind that I really despise) tends to default to Bateman’s “randy males/choosy females” model. But evo psych, which is primarily about the recent evolutionary history of human behavior, isn’t the same thing as sexual selection theory, which is about the evolution of mating systems in, well, pretty much anything that reproduces sexually.

And, in fact, new studies with better data do support Bateman’s model for other non-human animals. Just a couple weeks ago, Science published a very thorough study on pronghorn antelope that tracked the interaction of Bateman-style sexual selection and regular old natural selection over a decade. (One of that study’s coauthors, Stacey Dunn, is a personal friend — I’ll be running an interview with her over at The Molecular Ecologist next week.) That work is based on modern genetic markers, which have none of the drawbacks of Bateman’s method.

But all of this is sort of beside the point, as far as the rightness or wrongness of evolutionary psychology goes, since fruit flies and pronghorn aren’t humans. There’s a huge diversity of sexual expression across the animal kingdom, and it’s absurd to think that we can make any particular conclusion about recent human evolution based on what works for insects or ruminants.

If evolutionary psychologists would be wrong to use Bateman’s fruit flies to support a particular hypothesis about human sexuality — and they would be — then those of us who disagree with them don’t have any reason to crow about Bateman’s mistakes.◼

References

Byers, J. & Dunn, S. 2012. Bateman in nature: Predation on offspring reduces the potential for sexual selection. Science, 338: 802–804. doi: 10.1126/science.1224660.

Gowaty, P.A., Kim, Y.-K. & Anderson, W.W. 2012. No evidence of sexual selection in a repetition of Bateman’s classic study of Drosophila melanogaster. Proceedings of the National Academy of Sciences, doi: 10.1073/pnas.1207851109.

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The Molecular Ecologist: The Carnival of knowing what I know now

This advice won’t even cost you five cents. Image via nola.com.

That carnival of advice based on personal experience from previous career stages? Yep, it’s online today at The Molecular Ecologist. Head on over for a heaping helping of introspection, snark, and (mostly) sober reflection from across the science blogosphere.◼

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Science online, half-baked careers edition

Mount Saint Helens Mount Saint Helens. Photo by prorallypix.

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