The Molecular Ecologist

As we head into the weekend, here’s a few things that we’ve noticed that might be worth your screen time.
In the journals
Wilfert L., Jiggins F. 2012. The dynamics of reciprocal selective sweeps of host resistance and a parasite counter-adaptation in Drosophila. Evolution. DOI: 10.1111/j.1558-5646.2012.01832.x.

To illustrate the dynamics of this important but little studied form of coevolution, we have modeled an ongoing arms race between Drosophila melanogaster and the vertically transmitted sigma virus, using parameters we estimated in the field. We integrate these results with previous work showing that the spread of a resistance allele of the ref(2)P gene in the host was followed by the spread of a virus genotype, which overcomes this resistance. In line with these observations, our model predicts that there can be rapid selective sweeps in both the host and parasite, which can drive large changes in the prevalence of infection.

Curtis B. a., Tanifuji G., Burki F., Gruber A., Irimia M., et al. 2012. Algal genomes reveal evolutionary mosaicism and the fate of nucleomorphs. Nature. DOI: 10.1038/nature11681.

Cryptophyte and chlorarachniophyte algae are transitional forms in the widespread secondary endosymbiotic acquisition of photosynthesis by engulfment of eukaryotic algae. Unlike most secondary plastid-bearing algae, miniaturized versions of the endosymbiont nuclei (nucleomorphs) persist in cryptophytes and chlorarachniophytes. To determine why, and to address other fundamental questions about eukaryote–eukaryote endosymbiosis, we sequenced the nuclear genomes of the cryptophyte Guillardia theta and the chlorarachniophyte Bigelowiella natans.

Tibayrenc M., Ayala F.J. 2012. Reproductive clonality of pathogens: A perspective on pathogenic viruses, bacteria, fungi, and parasitic protozoa. Proc. Nat. Acad. Sci. USA. 109:E3305–13. DOI: 10.1073/pnas.1212452109.

We propose that clonal evolution in micropathogens be defined as restrained recombination on an evolutionary scale, with genetic exchange scarce enough to not break the prevalent pattern of clonal population structure, a definition already widely used for all kinds of pathogens, although not clearly formulated by many scientists and rejected by others.

In the blogosphere
Project EvoMap is putting biology labs and research groups on the, um, geographic visualization.
Are ecologists abusing ANOVA?

Speller C.F., Kemp B.M., Wyatt S.D., Monroe C., Lipe W.D., Arndt U.M., Yang D.Y. 2010. Ancient mitochondrial DNA analysis reveals complexity of indigenous North American turkey domestication. Proc. Nat. Acad. Sci. USA. 107:2807–12.

Although the cultural and nutritive importance of the turkey (Meleagris gallopavo) to precontact Native Americans and contem- porary people worldwide is clear, little is known about the domestication of this bird compared to other domesticates. Mitochondrial DNA analysis of 149 turkey bones and 29 coprolites from 38 archaeological sites (200 BC–AD 1800) reveals a unique domesticated breed in the precontact Southwestern United States. Phylogeographic analyses indicate that this domestic breed originated from outside the region, but rules out the South Mexican domestic turkey (Meleagris gallopavo gallopavo) as a progenitor. A strong genetic bottleneck within the Southwest turkeys also reflects intensive human selection and breeding. This study points to at least two occurrences of turkey domestication in precontact North America and illuminates the intensity and sophistication of New World animal breeding practices.

As we head into the weekend, here’s a few things that might be worth your screen-time.
In the journals
Shull, G. 1909. The “presence and absence” hypothesis. The American Naturalist 43:410–419. DOI: 10.1086/279073.

The “presence and absence” hypothesis assumes that what appears to be a pair of charactersin Mendelian inheritance is really the presence and absence of a single character. This hypothesis has now won the support of most of the leading experimental students of heredity. The fact that the absence of certain characters dominates over their presence has appeared to some to be a difficulty. This paper shows that no such difficultyis involved and simple chemical experimentsare cited which, if duplicated among plants and animals, as they no doubt are, would give the dominance of absence over presence without recourse to “inhibiting factors.”

Wang, I. J., R. E. Glor and J. B. Losos. 2012. Quantifying the roles of ecology and geography in spatial genetic divergence. Ecology Letters. DOI: 10.1111/ele.12025.

Both ecological and geographical factors can reduce gene flow, which can lead to population divergence, but we know little of the relative strengths of these phenomena in nature. Here, we use a novel application of structural equation modelling to quan- tify the contributions of ecological and geographical isolation to spatial genetic divergence in 17 species of Anolis lizards.

In the blogosphere
Have you submitted your advice to our “Knowing what I know now” carnival? Why not? Go do that now.
Granting agencies are starting to accept web traffic as an impact metric.
“It is crucial that scientists take more career risks and sound a more realistic, more desperate, note on the global-warming problem.”