Genetics February 1, 2012 vol. 190 no. 2 NP
Scrambling eggs: Meiotic drive and the evolution of female recombination rates, pp. 709–723
Yaniv Brandvain and Graham Coop
Despite decades of research on the evolution of sex and recombination, the basis of differences in recombination rates between the sexes is not well understood. According to these authors, a consistent sex difference—the opportunity for female meiotic drive presented by the asymmetry of female gametogenesis—can favor an evolutionary modification of the female recombination rate. They discuss the interpretation and implications of this finding in light of our knowledge of the genetic control of recombination.
A conserved transcriptional regulator governs fungal morphology in widely diverged species, pp. 511–521
Christopher W. Cain, Matthew B. Lohse, Oliver R. Homann, Anita Sil, and Alexander D. Johnson
This article shows that orthologous transcriptional regulators from three highly diverged fungal species recognize the same DNA sequence, yet regulate three distinct morphological transitions (white-opaque switching in Candida albicans, the yeast to mycelial transition in Histoplasma capsulatum, and pseudohyphal growth in Saccharomyces cerevisiae). Extensive gains and losses of cis-regulatory sequences are, at least in part, responsible for the different phenotypic outputs produced by these orthologous and biochemically similar transcriptional regulators.
The genome architecture of the Collaborative Cross Mouse Genetics reference population, pp. 389–401
Collaborative Cross Consortium
This issue of GENETICS presents 7 groundbreaking articles that describe a unique genetic resource: the Collaborative Cross (CC) reference population, derived from eight diverse, inbred strains of mouse. Our sister journal G3 has 7 additional articles. This particular article provides the first joint analysis of the genomes of the CC lines. It provides the first comprehensive view of the CC lines that are being released to the public, along with their genotypes, founder haplotype inference data, and subspecific origin and ancestral haplotype diversity data.
Low-pass genome-wide sequencing and variant inference using identity-by-descent in an isolated human population, pp. 679–689
A. Gusev, M. J. Shah, E. E. Kenny, A. Ramachandran, J. K. Lowe, J. Salit, C. C. Lee, E. C. Levandowsky, T. N. Weaver, Q. C. Doan, H. E. Peckham, S. F. McLaughlin, M. R. Lyons, V. N. Sheth, M. Stoffel, F. M. De La Vega, J. M. Friedman, J. L. Breslow, and I. Pe'er
This article describes a genome-wide analysis of an isolated human population, with the goal of a saturating identification of new genetic variants. The authors develop a novel algorithm for selecting sequence candidates from a study population that allows them to maximize the amount of novel variation that can be discovered in the selected samples. Their findings suggest that the sequenced individuals can be used to infer novel variation in the rest of the population with very high accuracy.
Fine-scale estimation of location of birth from genome-wide single-nucleotide polymorphism data, pp. 669–677
Clive J. Hoggart, Paul F. O'Reilly, Marika Kaakinen, Weihua Zhang, John C. Chambers, Jaspal S. Kooner, Lachlan J. M. Coin, and Marjo-Riitta Jarvelin
Humans generally choose their sexual mates from nearby locations, creating a link between individuals' DNA and their birthplace. These investigators employ principal component analysis to infer the origin of individuals from genetic data alone. Their method estimates origin extremely accurately, providing the most accurate location estimator from genetic data so far. Applications include genetic association studies, population genetics, and forensics.
Frameshift mutagenesis: The roles of primer–template misalignment and the nonhomologous end-joining pathway in Saccharomyces cerevisiae, pp. 501–510
Kevin Lehner, Sarah V. Mudrak, Brenda K. Minesinger, and Sue Jinks-Robertson
Small insertions or deletions of nucleotides typically occur in simple repeats, and are thought to arise through primer-template misalignment during DNA replication. This article shows that the nonhomologous endjoining pathway provides an additional mechanism for generating frameshift mutations in short runs, and that this pathway is uniquely required for the creation of tandem duplications from noniterated sequence.
New insights into the genetics of in vivo induction of maternal haploids, the backbone of doubled haploid technology in maize, pp. 781–793
Vanessa Prigge, Xiaowei Xu, Liang Li, Raman Babu, Shaojiang Chen, Gary N. Atlin, and Albrecht E. Melchinger
Homozygous inbred maize can arise by in vivo induction of haploidy followed by chromosome duplication. The authors of this article demonstrate through comparative quantitative trait locus mapping that induction of maternal haploids is controlled by a major locus that shows strong segregation distortion against the inducer allele, indicating that natural selection disfavors haploid induction ability. Their conclusions provide significant new insights into the biological process underlying haploid induction in maize.
Huntingtin aggregation kinetics and their pathological role in a Drosophila Huntington's disease model, pp. 581–600
Kurt R. Weiss, Yoko Kimura, Wyan-Ching Mimi Lee, and J. Troy Littleton
This article describes the use of Drosophila to view the aggregation of Huntingtin, the protein that causes Huntington's disease. The authors image fluorescently tagged pathogenic human Huntingtin and find that new aggregates can form in neurons within 12 hours, while preexisting aggregates rapidly accumulate new Huntingtin protein within minutes. A haplo-insufficiency suppressor screen to identify suppressors of toxicity suggests that both soluble and aggregated Huntingtin contribute to neuronal dysfunction.
This Month's Perspectives
James F. Crow and the stochastic theory of population genetics, pp. 287–290
Warren J. Ewens
This Perspectives article recounts two major controversies of the stochastic theory of population genetics. The first concerned the validity of Wright's "shifting balance" theory of evolution, in which random changes in allelic frequencies played a key role. The second was the neutral theory of evolution, which claimed that most gene fixation events in evolution arise from random changes in frequencies of selectively neutral alleles. Crow was closely involved with the authors of both theories, and marshaled a balanced and objective assessment of both theories.
This Month in the American Journal of Human Genetics
The Arabian cradle: Mitochondrial relicts of the first steps along the southern route out of Africa, Am. J. Hum. Genet. 90(2)
Verónica Fernandes, Farida Alshamali, Marco Alves, Marta D. Costa,Joana B. Pereira, Nuno M. Silva, Lotfi Cherni, Nourdin Harich, Viktor Cerny, Pedro Soares, Martin B. Richards, and Luísa Pereira
Although it is common knowledge that humans originated in Africa, the nature of the path taken on the way to populating Europe and Asia has remained controversial. In this study of mitochondrial genetic diversity, the authors analyze three rare, geographically dispersed, western Eurasian haplogroups (N1, N2, and X). Comparisons of over 300 mitochondrial genomes show that these non-African haplogroups share an ancient Arabian ancestry, coalescing ∼60kya, a time frame consistent with out-of-Africa migration into western Eurasia. Together with corroborating archaeological evidence, these findings provide strong evidence that Arabia was a major staging area for the spread of modern humans.
Volume 190 Issue 2, February 2012
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