Hypotonically-spread pachytene chromosomes from maize showing synaptonemal complexes (SCs, light blue lines) with kinetochores (light blue balls). The chromatin (stained blue with DAPI) has been dispersed by the spreading procedure and appears as a fuzzy blue coat along the length of each SC. Fluorescence in situ hybridization (FISH, red) of the 180 bp knob repeat shows that the chromatin of the interstitial knobs occupies well-defined SC segments, and at least some chromatin loops from the knobs extend much farther from their SC attachment sites than the rest of the chromatin. By combining FISH of knob repeats with MLH1 immunolabeling to reveal crossovers, Stack et al. determined that meiotic crossing over is not suppressed along the SC in knob heterochromatin.

Check out the September issue of GENETICS by looking at the highlights or the full table of contents!

ISSUE HIGHLIGHTS

MicroRNAs that contribute to coordinating the immune response in Drosophila melanogaster, pp. 163-178

Magda L. Atilano, Marcus Glittenberg, Annabel Monteiro, Richard R. Copley, and Petros Ligoxygakis

Atilano et al. present a Drosophila post-infection survival screen that takes advantage of a library of miRNA mutant flies. Using genome wide microarray and bioinformatics surveys to pinpoint the NF-kB-regulated fraction of these miRNAs, they reveal a layer of miRNA-mediated immune regulation at the whole organism level.

Regulation of lysosomal function by the DAF-16 Forkhead transcription factor couples reproduction to aging in Caenorhabditis elegans, pp. 83-101

Kunal Bax, Ata Ghavidel, Brandon Waddell, Troy A. Harkness, and Carlos E. de Carvalho

Reproduction and aging are intertwined. While lifespan and reproductive strategies vary greatly among animals, the progeny production period generally coincides with the stage in life when the organism is the fittest. Here Baxi et al. show that, in Caenorhabditis elegans, the active regulation of lysosomal pH in the soma by signals from the gonad is one mechanism to ensure that animals delay somatic decline until reproduction is complete.

A gene implicated in activation of retinoic acid receptor targets is a novel renal agenesis gene in humans, pp. 215-228

Patrick D. Brophy, Maria Rasmussen, Mrutyunjaya Parida, Greg Bonde, Benjamin W. Darbro, Xiaojing Hong, Jason C. Clarke, Kevin A. Peterson, James Denegre, Michael Schneider, Caroline R. Sussman, Lone Sunde, Dorte L. Lildballe, Jens Michael Hertz, Robert A. Cornell, Stephen A. Murray, and J. Robert Manak

Renal agenesis is a devastating birth defect, and although genes encoding retinoic acid signaling components have been shown to be important for renal development in mice, no human genes of this pathway have been implicated in renal agenesis until now. Here, Brophy et al. identify the first such gene, GREB1L, and provide validation for its involvement in renal agenesis through a novel approach that takes advantage of genome editing in F0 mice.

Contrasting determinants of mutation rates in germline and soma, pp. 255-267

Chen Chen, Hongjian Qi, Yufeng Shen, Joseph Pickrell, and Molly Przeworski

A number of genomic features influence regional mutation rates in germline and soma. To examine if some factors behave differently in the two tissue types, Chen et al. applied a multivariate regression model to exome data from germline and soma, including expression levels and other features as predictors. They also considered the mutational strand asymmetry in soma and germline and its correlation with expression levels. They find evidence that the balance of damage and repair during transcription may differ between germline and soma.

Remarkable evolutionary conservation of antiobesity ADIPOSE/ WDTC1 homologs in animals and plants, pp. 153-162

Eric Ducos, Valentin Verges, Thomas Duge de Bernonville, Nathalie Blanc, Nathalie Giglioli-Guivarch, and Christelle Dutilleul

Ducos et al. report that the farnesylated protein ASG2 is the Arabidopsis ortholog of human WDCT1, which controls fat accumulation. Both proteins harbor WD40 domains, tetratricopeptide repeats, and a C-terminal, farnesylatable CaaX-box. ASG2 dysfunction leads to the production of “obese” seeds with enhanced fat content. Their results highlight a remarkable evolutionary conserved role for WDTC1-like proteins in fat metabolism in both the plant and animal kingdoms.

Histone acetylation, not stoichiometry, regulates linker histone binding in Saccharomyces cerevisiae, pp. 347-355

Mackenzie B. D. Lawrence, Nicolas Coutin, Jennifer K. Choi, Benjamin J. E. Martin, Nicholas A. T Irwin, Barry Young, Christopher Loewen, and LeAnn J. Howe

Linker histones play an important role in shaping chromatin structure, but the regulation of their interactions with chromatin is poorly understood. In this study, Lawrence et al. explore the regulation of linker histone binding in Saccharomyces cerevisiae, showing that core histone acetylation negatively regulates linker histone binding. These results provide important insight into how chromatin structure is regulated and maintained to both facilitate and repress transcription.

Benchmarking relatedness inference methods with genome-wide data from thousands of relatives, pp. 75-82

Monica D. Ramstetter, Thomas D. Dyer, Donna M. Lehman, Joanne E. Curran, Ravindranath Duggirala, John Blangero, Jason G. Mezey, and Amy L. Williams

Relatedness inference is an essential component of many genetic analyses and popular in consumer genetic testing. Ramstetter et al. evaluate twelve relatedness inference methods and show that all methods have high accuracy for first- and second- degree relatives but struggle to infer higher relatedness degrees. The methods typically infer unrelated individuals correctly, suggesting a low rate of false positives. Relatedness inference is likely to become more important as sample sizes increase and the proportion of samples with a relative in a given dataset grows.

A model for epigenetic inhibition via transvection in the mouse, pp. 129-138

Juan D. Rodriguez, Dexter A. Myrick, Ilaria Falciatori, Michael A. Christopher, Teresa W. Lee, Gregory J. Hannon, and David J. Katz

Transvection—a phenomenon in which the allele on one chromosome genetically interacts with its paired allele on the homologous chromo-some—is one of the oldest and most mysterious genetic phenomena, but there are only two documented cases in mammals. Rodriguez et al. present an additional example of mammalian transvection initiated by a meiotically expressed Cre allele. They show that the transvection does not appear to be regulated by DNA methylation and is dependent upon parental history, suggesting an epigenetic phenomenon and providing a new model for studying the underlying mechanism in mammals.

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