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Bailey N.W.,Center for Biological Diversity | Veltsos P.,Center for Biological Diversity | Tan Y.-F.,Center for Evolutionary Biology | Tan Y.-F.,University of Western Australia | And 3 more authors.
G3: Genes, Genomes, Genetics | Year: 2013

Field crickets (family Gryllidae) frequently are used in studies of behavioral genetics, sexual selection, and sexual conflict, but there have been no studies of transcriptomic differences among different tissue types. We evaluated transcriptome variation among testis, accessory gland, and the remaining wholebody preparations from males of the field cricket, Teleogryllus oceanicus. Non-normalized cDNA libraries from each tissue were sequenced on the Roche 454 platform, and a master assembly was constructed using testis, accessory gland, and whole-body preparations. A total of 940,200 reads were assembled into 41,962 contigs, to which 36,856 singletons (reads not assembled into a contig) were added to provide a total of 78,818 sequences used in annotation analysis. A total of 59,072 sequences (75%) were unique to one of the three tissues. Testis tissue had the greatest proportion of tissue-specific sequences (62.6%), followed by general body (56.43%) and accessory gland tissue (44.16%). We tested the hypothesis that tissues expressing gene products expected to evolve rapidly as a result of sexual selection-testis and accessory gland-would yield a smaller proportion of BLASTx matches to homologous genes in the model organism Drosophila melanogaster compared with whole-body tissue. Uniquely expressed sequences in both testis and accessory gland showed a significantly lower rate of matching to annotated D. melanogaster genes compared with those from general body tissue. These results correspond with empirical evidence that genes expressed in testis and accessory gland tissue are rapidly evolving targets of selection. © 2013 Bailey et al.

Donnelly M.P.,Yale University | Paschou P.,Democritus University of Thrace | Grigorenko E.,Yale University | Gurwitz D.,National Laboratory for the Genetics of Israeli Populations | And 20 more authors.
American Journal of Human Genetics | Year: 2010

The polymorphic inversion on 17q21, sometimes called the microtubular associated protein tau (MAPT) inversion, is an ∼900 kb inversion found primarily in Europeans and Southwest Asians. We have identified 21 SNPs that act as markers of the inverted, i.e., H2, haplotype. The inversion is found at the highest frequencies in Southwest Asia and Southern Europe (frequencies of ∼30%); elsewhere in Europe, frequencies vary from < 5%, in Finns, to 28%, in Orcadians. The H2 inversion haplotype also occurs at low frequencies in Africa, Central Asia, East Asia, and the Americas, though the East Asian and Amerindian alleles may be due to recent gene flow from Europe. Molecular evolution analyses indicate that the H2 haplotype originally arose in Africa or Southwest Asia. Though the H2 inversion has many fixed differences across the ∼900 kb, short tandem repeat polymorphism data indicate a very recent date for the most recent common ancestor, with dates ranging from 13,600 to 108,400 years, depending on assumptions and estimation methods. This estimate range is much more recent than the 3 million year age estimated by Stefansson et al. in 2005.1. © 2010 The American Society of Human Genetics.

Zhang Y.,Fudan University | Ma T.,Center for Evolutionary Biology | Yang S.,Center for Evolutionary Biology | Xia M.,Center for Evolutionary Biology | And 4 more authors.
Molecular and Cellular Biochemistry | Year: 2011

High-mobility group A1 (HMGA1) is a non-histone chromatin protein that has the ability to regulate the transcriptional activity of many genes. Overexpression of HMGA1 is associated with malignant cellular behavior in a range of human cancers but the underlying mechanism is largely unknown. Here we showed that in a cohort of non-small cell lung cancer (NSCLC) tumors, HMGA1 overex-pression was immediately associated with enhanced expression of an oncogenic miRNA, namely, miR-222. Chromatin immunoprecipitation (CHIP) assay revealed that HMGA1 directly binds to the proximal promoter of miR-222 in NSCLC cells. We further showed that HMGA1 silencing reduced miR-222 transcriptional activity, whereas forced HMGA1 expression increased it, indicating that miR-222 is directly regulated by HMGA1. Based on in silico prediction, one of the putative targets of miR-222 is phosphatase 2A subunit B (PPP2R2A) which inhibits Akt phosphorylation (p-Akt). We demonstrated that miR-222 inhibited protein expression of PPP2R2A in NSCLC cells by directly interacting with its 3′-UTR region, leading to an obvious increase of p-Akt. HMGA1 silencing augmented PPP2R2A protein expression and inhibited Akt signaling, resulting in significantly retarded cell growth response to IGF-I. These results suggested that HMGA1 is a positive regulator of miR-222, and HMGA1 overexpression might contribute to dysregulation of Akt signaling in NSCLC. © Springer Science+Business Media, LLC. 2011.

Evans J.P.,Center for Evolutionary Biology | Rahman M.M.,Center for Evolutionary Biology | Gasparini C.,Center for Evolutionary Biology
Journal of Evolutionary Biology | Year: 2015

The role that genotype-by-environment interactions (GEIs) play in sexual selection has only recently attracted the attention of evolutionary biologists. Yet GEIs can have profound evolutionary implications by compromising the honesty of sexual signals, maintaining high levels of genetic variance underlying their expression and altering the patterns of genetic covariance among fitness traits. In this study, we test for GEIs in a highly sexually dimorphic freshwater fish, the guppy Poecilia reticulata. We conducted an experimental quantitative genetic study in which male offspring arising from a paternal half-sibling breeding design were assigned to differing nutritional 'environments' (either high or low feed levels). We then determined whether the manipulation of diet quantity influenced levels of additive genetic variance and covariance for several highly variable and condition-dependent pre- and post-copulatory sexual traits. In accordance with previous work, we found that dietary limitation had strong phenotypic effects on numerous pre- and post-copulatory sexual traits. We also report evidence for significant GEI for several of these traits, which in some cases (area of iridescence and sperm velocity) reflected a change in the rank order of genotypes across different nutritional environments (i.e. ecological crossover). Furthermore, we show that genetic correlations vary significantly between nutritional environments. Notably, a highly significant negative genetic correlation between iridescent coloration and sperm viability in the high food treatment broke down under dietary restriction. Taken together, these findings are likely to have important evolutionary implications for guppies; ecological crossover may influence sexual signal reliability in unstable (nutritional) environments and contribute towards the extreme levels of polymorphism in sexual traits typically reported for this species. Furthermore, the presence of environment-specific genetic covariance suggests that trade-offs measured in one environment may not be indicative of genetic constraints in others. © 2015 European Society For Evolutionary Biology.

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