Project description:Plant architecture is central to yield and has been at the core of crop domestication and improvement. In cereals, inflorescence branching and leaf angle are important traits that contribute to planting density and yield potential. Several classical maize mutants show disruptions in both traits, suggesting a core regulatory network underlies pleiotropy between them. Here, we investigate regulatory modules that contribute to architectural pleiotropy between tassel branch number (TBN) and leaf angle (LA) in maize by defining transcriptional networks that function in lateral organ boundaries to promote development of these morphologically distinct organs. Using a set of nine mutants with specific developmental defects in one or both traits, we generated dynamic, context-specific gene regulatory maps that describe ligule and tassel branch development at the molecular level. Mutants introgressed into B73 and control plants were grown in environmentally controlled chambers and precisely-staged tassel primordia were hand-dissected at two stages: right before and after first primary branches initiated. Two stages capturing early development of the ligular region, including the shoot apical meristem, were also collected from mutants with LA defects. RNA-seq was performed on 140 samples and integrated into gene regulatory and co-expression networks, which were extended to include publicly available transcription factor occupancy maps for important developmental regulators, chromatin accessibility maps and natural variation to help prioritize novel genes and regulatory elements underlying diversity in LA and tassel branching phenotypes. We also used these transcriptional networks to guide multi-trait genome-wide association studies (GWAS) based on three years of field phenotyping TBN and LA traits in over 500 diverse maize lines. Various network-assisted GWAS approaches were used to identify polymorphisms in candidate genes that associate with these architecture traits and the pleiotropy between them. Our data provide novel insight into regulatory mechanisms controlling architectural pleiotropy that can be used for targeted crop improvement.
2025-02-03 | GSE180593 | GEO
Project description:Genetic Mapping and Functional Analysis of a tassel branch number Mutant in maize
Project description:Directional selection in the domestication of fish species has resulted in rapid gains of growth, body size, and other production-relevant traits in relatively few generations. While there is clear evidence of genetic divergence contributing to selection-related phenotypic changes, emerging research suggests that intergenerational epigenetic inheritance may also be a relevant mechanism explaining rapid evolutionary change in domestic fish lines. Epigenetic changes have also been implicated in fish species’ responses to warming associated with climate change. Domestic lines of Brook Charr (Salvelinus fontinalis) are the primary source of fish used for recreational fisheries stocking in many parts of Eastern North America and there are concerns about how these fish will fare when stocked into lakes in the coming decades. We jointly investigated the effects of directional selection for performance traits (i.e., absence of early sexual maturation and increased growth) and exposure to elevated temperatures on DNA methylation in sperm cells of two experimental lines (hereafter: Selected and Control lines) of Brook Charr . We used whole-genome bisulfite sequencing to characterize DNA methylation at over 17 million methylated sites and identified 393 selection-related differentially methylated regions (DMR). The putative functions of genes in proximity to these DMRs are consistent with well-characterized phenotypic differences between the lines, including lipid metabolism and precocial maturation, and support the hypothesis that rapid evolution of traits may be partially mediated by epigenetic inheritance. We subsequently detected 85 warming-related DMRs in the Control line and 302 DMRs in the Selected line. None of these regions were shared between the two lines, indicating that the directional selection regime significantly altered the environmentally sensitive epigenetic landscape.
Project description:Here we used artificial selection to assimilate a seasonal wing color phenotype from a naturally plastic population of butterflies. Using SNP association and RNAseq we mapped three genes responsible for wing color fixation, including the color pattern supergene cortex. Combined with endocrine and chromatin accessibility assays, we found that the rapid transition of wing coloration from an environmentally determined trait to a fixed, genetic trait occurred through selection on cis-regulatory alleles of genes with wing-specific functions, not by changes in environmental detection or hormone signaling.
Project description:Here we used artificial selection to assimilate a seasonal wing color phenotype from a naturally plastic population of butterflies. Using SNP association and RNAseq we mapped three genes responsible for wing color fixation, including the color pattern supergene cortex. Combined with endocrine and chromatin accessibility assays, we found that the rapid transition of wing coloration from an environmentally determined trait to a fixed, genetic trait occurred through selection on cis-regulatory alleles of genes with wing-specific functions, not by changes in environmental detection or hormone signaling.
Project description:Here we used artificial selection to assimilate a seasonal wing color phenotype from a naturally plastic population of butterflies. Using SNP association and RNAseq we mapped three genes responsible for wing color fixation, including the color pattern supergene cortex. Combined with endocrine and chromatin accessibility assays, we found that the rapid transition of wing coloration from an environmentally determined trait to a fixed, genetic trait occurred through selection on cis-regulatory alleles of genes with wing-specific functions, not by changes in environmental detection or hormone signaling.
Project description:One method of directional cloning of fragmented mRNA is based on single strand RNA ligation, for which ligation bias occurrs if the adapters have single sequences. The sequencing bias affects the mRNA quantification and subsequently the differential expression analysis. High definition (HD) adapters [Sorefan et al 2012, Xu et al 2015] can be used to diminish the cloning bias during library construction. HD adapters and standard illumina adapters were used to construct mRNA-seq libraries for a side by side comparison.
Project description:Directional transport of auxin is critical for inflorescence and floral development in flowering plants, but the role of auxin influx carriers (AUX1 proteins) has been largely overlooked. Taking advantage of available AUX1 mutants in Setaria viridis and maize, we uncover previously unreported aspects of plant development that are affected by auxin influx, including higher order branches in the inflorescence, stigma branch number, and glume (floral bract) development, and plant fertility. However, disruption of auxin flux does not affect all parts of the plant, with little obvious effect on inflorescence meristem size, time to flowering, and anther morphology. In double mutant studies in maize, disruptions of ZmAUX1 also affect vegetative development. A GFP-tagged construct of SvAUX1 under its native promoter showed that the AUX1 protein localizes to the plasma membrane of outer tissue layers in both roots and inflorescences, and accumulates specifically in inflorescence branch meristems, consistent with the mutant phenotype and expected auxin maxima. RNA-seq analysis finds that most gene expression modules are conserved between mutant and wildtype plants, with only a few hundred genes differentially expressed in spp1 inflorescences. Using CRISPR-Cas9 technology, we disrupted SPP1 and the other four AUX1 homologs in S. viridis. SvAUX1/SPP1 has a larger effect on inflorescence development than the others, although all contribute to plant height, tiller formation, leaf, and root development. The AUX1 importers are thus not fully redundant in S. viridis. Our detailed phenotypic characterization plus a stable GFP-tagged line offer tools for future dissection of the function of auxin influx proteins.
Project description:Background: Gene expression variation is a phenotypic trait of particular interest as it represents the initial link between genotype and other phenotypes. Analyzing how such variation apportions among and within groups allows for the evaluation of how genetic and environmental factors influence such traits. It also provides opportunities to identify genes and pathways that may have been influenced by non-neutral processes. Here we use a population genetics framework and next generation sequencing to evaluate how gene expression variation is apportioned among four human groups in a natural biological tissue, the placenta. Results: We estimate that on average, 33.2%, 58.9% and 7.8% of the placental transcriptome is explained by variation within individuals, among individuals and among human groups, respectively. Additionally, when technical and biological traits are included in models of gene expression they account for roughly 2% of total gene expression variation. Notably, the variation that is significantly different among groups is enriched in biological pathways associated with immune response, cell signaling and metabolism. Many biological traits demonstrated correlated changes in expression in numerous pathways of potential interest to clinicians and evolutionary biologists. Finally, we estimate that the majority of the human placental transcriptome (65% of expressed genes) exhibits expression profiles consistent with neutrality; the remainder are consistent with stabilizing selection (26%), directional selection (4.9%), or diversifying selection (4.8%). Conclusion: We apportion placental gene expression variation into individual, population and biological trait factors and identify how each influence the transcriptome. Additionally, we advance methods to associate expression profiles with different forms of selection. Placental mRNA was sequenced on an Illumina GAIIx. Samples were derived from 4 human groups, 10 individuals per group, 2 samples per individual
Project description:Evolutionary studies are often limited by missing data that are critical to understanding the history of selection. Selection experiments, which reproduce rapid evolution under controlled conditions, are excellent tools to study how genomes evolve under selection. Here we present a genomic dissection of the Longshanks selection experiment, in which mice were selectively bred over 20 generations for longer tibiae relative to body mass, resulting in 13% longer tibiae in two replicates. We synthesized evolutionary theory, genome sequences and molecular genetics to understand the selection response and found that it involved both polygenic adaptation and discrete loci of major effect, with the strongest loci likely to be selected in parallel between replicates. We show that selection may favor de-repression of bone growth through inactivating two limb enhancers of an inhibitor, Nkx3-2. Our integrative genomic analyses thus show that it is possible to connect individual base-pair changes to the overall selection response.