Newswise Bethesda, MDJune 14, 2012 Listed below are the selected highlights for the June 2012 issue of the Genetics Society of Americas journal, GENETICS. The June issue is available online at www.genetics.org/content/current. Please credit GENETICS, Vol. 191, JUNE 2012, Copyright 2012.

Please feel free to forward to colleagues who may be interested in these articles.

ISSUE HIGHLIGHTS

APL-1, the Alzheimers amyloid precursor protein in Caenorhabditis elegans, modulates multiple metabolic pathways throughout development, pp. 493507 Collin Y. Ewald, Daniel A. Raps, and Chris Li A hallmark of Alzheimers disease is the deposition of senile plaques, whose major component is the beta-amyloid peptide, which is a cleavage product of the amyloid precursor protein (APP). The function of APP and its cleavage products is still unclear. This article reports that the Caenorhabditis elegans APP-related protein APL-1 has multiple functions during development, including modulating the insulin pathway.

Population genetics models of local ancestry, pp. 607619 Simon Gravel Genomes are mosaics of chromosomal tracts that originate from a finite number of ancestors. These mosaics, which are shaped by historical migration patterns, are key to understanding genomic diversity in complex populations. This article presents gene flow models for inferring migration history using such patterns. When applied to HapMap African-American (ASW) data, a two-epoch migration model agrees with the data better than the commonly used single-migration model.

Synaptic polarity depends on phosphatidylinositol signaling regulated by myo-inositol monophosphatase in Caenorhabditis elegans, pp. 509521 Tsubasa Kimata, Yoshinori Tanizawa, Yoko Can, Shingo Ikeda,Atsushi Kuhara, and Ikue Mori Lithium relieves bipolar disorder by inhibiting the evolutionarily conserved enzyme myo-inositol monophosphatase (IMPase), which is essential for polarized localization of synaptic molecules. These authors show that mutations in two enzymes that degrade membrane phosphatidylinositol 4,5-bisphosphate (PIP2) suppress the synaptic defects of IMPase mutants and confer resistance to lithium treatment. These results provide the first in vivo evidence that lithium impairs neuronal PIP2 synthesis through inhibition of IMPase.

Analysis of Cryptococcus neoformans sexual development reveals rewiring of the pheromone-response network by a change in transcription factor identity, pp. 435449 Emilia K. Kruzel, Steven S. Giles, and Christina M. Hull Gene regulatory networks evolve, sometimes radically. This article describes the pheromone response network of the human pathogen Cryptococcus neoformans. The authors map transcriptional regulatory changes that occur during sexual development leading to the discovery of a key cis-regulatory element and its binding protein. The resulting regulatory architecture could not have been predicted based on comparative sequence analyses.

A non-Mendelian MAPK-generated hereditary unit controlled by a second MAPK pathway in Podospora anserina, pp. 419433 Herv Lalucque, Fabienne Malagnac, Sylvain Brun, Sbastien Kicka,and Philippe Silar There are many ways to produce a prion, and this article describes yet another one. The Podospora anserina PaMpk1 MAP kinase signaling pathway can generate C, a hereditary unit resembling prions. These authors show that another MAP kinase pathway, PaMpk2, controls the generation of C by activating PaMpk1, revealing unexpectedly complex regulation of a prion-like trait.

Allopolyploidization lays the foundation for evolution of distinct populations: Evidence from analysis of synthetic Arabidopsis allohexaploids, pp. 535547 Starr C. Matsushita, Anand P. Tyagi, Gerad M. Thornton, J. Chris Pires, and Andreas Madlung Allopolyploidycarrying complete chromosome sets of at least two different specieshas been seen as a mechanism for instant speciation. This article shows that different somatic cells of the same neoallopolyploid individual can exhibit different karyotypes, and that somatic mosaics can persist in subsequent generations. The authors characterize and quantify aneuploidy over seven generations in several sibling lines of a synthetic allopolyploid. Their results suggest that this phenomenon has the potential to lead not only to instant speciation but also to instant radiation.

The nearly neutral and selection theories of molecular evolution under the Fisher geometrical framework: Substitution rate, population size, and complexity, pp. 523534 Pablo Razeto-Barry, Javier Daz, and Rodrigo A. Vsquez This article puts forth that nearly neutral evolution cannot explain the high rate of fixations driven by positive selection found in DNA sequences. The authors use Fishers geometrical model (FGM) to simulate evolution from biologically interpretable distributions of mutations. They find that nearly neutral and selection scenarios predict molecular patterns different from previous models. In a selective scenario in the FGM, evolutionary rate depends not on population size, but rather on the complexity of organisms and mutation size.

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