scholarly journals Characterization of a major QTL and Genome-Wide Epistatic Interactions for the Transformation of Single Spikelet in Teosinte Ears into Paired Spikelets in Maize Ears During Maize Domestication

Author(s):  
Zhengjie Chen ◽  
Kun Hu ◽  
Yong Yin ◽  
Dengguo Tang ◽  
Jixing Ni ◽  
...  

Abstract Maize ear carries paired spikelets, whereas the ear of its wild ancestor, teosinte, bears single spikelets. However, little is known about the genetic basis of the processes of transformation of single spikelets in teosinte ear to paired spikelets in maize ear. In this study, a two-ranked, paired-spikelets primitive maize and a two-ranked, single-spikelet teosinte were utilized to develop an F2 population, and QTL mapping for single vs. paired spikelets (PEDS) was performed. Two QTL (qPEDS1.1 and qPEDS3.1) for PEDS located on chromosomes 1L and 3S were identified in the 162 F2 plants using the inclusive composite interval mapping of additive (ICIM-ADD) module, explaining 1.93% and 23.79% of the phenotypic variance, respectively. Out of the 409 F2 plants, 43 plants with PEDS = 0% and 43 plants with PEDS > 20% were selected for selective genotyping; the QTL (qPEDS3.1) accounting for 64.01% of the phenotypic variance for PEDS was also detected. Moreover, the QTL (qPEDS3.1) was validated in three environments, which explained 31.05%, 38.94% and 23.16% of the phenotypic variance, respectively. In addition, 50 epistatic QTLs were detected in 162 F2 plants using the two-locus epistatic QTL (ICIM-EPI) module; they were distributed on all 10 chromosomes and explained 94.40% of the total phenotypic variance. The results contribute to a better understanding of the genetic basis of domestication of paired spikelets and provide a genetic resource for future map-based cloning; in addition, the systematic dissection of epistatic interactions underlies a theoretical framework for overcoming epistatic effects on QTL fine mapping.

Genetics ◽  
1999 ◽  
Vol 153 (3) ◽  
pp. 1233-1243 ◽  
Author(s):  
David R Shook ◽  
Thomas E Johnson

Abstract We have identified, using composite interval mapping, quantitative trait loci (QTL) affecting a variety of life history traits (LHTs) in the nematode Caenorhabditis elegans. Using recombinant inbred strains assayed on the surface of agar plates, we found QTL for survival, early fertility, age of onset of sexual maturity, and population growth rate. There was no overall correlation between survival on solid media and previous measures of survival in liquid media. Of the four survival QTL found in these two environments, two have genotype-environment interactions (GEIs). Epistatic interactions between markers were detected for four traits. A multiple regression approach was used to determine which single markers and epistatic interactions best explained the phenotypic variance for each trait. The amount of phenotypic variance accounted for by genetic effects ranged from 13% (for internal hatching) to 46% (for population growth). Epistatic effects accounted for 9–11% of the phenotypic variance for three traits. Two regions containing QTL that affected more than one fertility-related trait were found. This study serves as an example of the power of QTL mapping for dissecting the genetic architecture of a suite of LHTs and indicates the potential importance of environment and GEIs in the evolution of this architecture.


2016 ◽  
Vol 19 (11) ◽  
pp. 1454-1462 ◽  
Author(s):  
Arjun Krishnan ◽  
Ran Zhang ◽  
Victoria Yao ◽  
Chandra L Theesfeld ◽  
Aaron K Wong ◽  
...  

2015 ◽  
Vol 282 (1806) ◽  
pp. 20150156 ◽  
Author(s):  
Arild Husby ◽  
Takeshi Kawakami ◽  
Lars Rönnegård ◽  
Linnéa Smeds ◽  
Hans Ellegren ◽  
...  

Understanding the genetic basis of traits involved in adaptation is a major challenge in evolutionary biology but remains poorly understood. Here, we use genome-wide association mapping using a custom 50 k single nucleotide polymorphism (SNP) array in a natural population of collared flycatchers to examine the genetic basis of clutch size, an important life-history trait in many animal species. We found evidence for an association on chromosome 18 where one SNP significant at the genome-wide level explained 3.9% of the phenotypic variance. We also detected two suggestive quantitative trait loci (QTLs) on chromosomes 9 and 26. Fitness differences among genotypes were generally weak and not significant, although there was some indication of a sex-by-genotype interaction for lifetime reproductive success at the suggestive QTL on chromosome 26. This implies that sexual antagonism may play a role in maintaining genetic variation at this QTL. Our findings provide candidate regions for a classic avian life-history trait that will be useful for future studies examining the molecular and cellular function of, as well as evolutionary mechanisms operating at, these loci.


Author(s):  
Camila U. Braz ◽  
Troy N. Rowan ◽  
Robert D. Schnabel ◽  
Jared E. Decker

AbstractBackgroundUnderstanding the genetic basis of genotype-by-environment interactions (GxE) is crucial to understand environmental adaptation in mammals and improve the sustainability of agricultural production. In addition, GxE information could also be useful to predict the vulnerability of populations to climate change.ResultsHere, we present an extensive study investigating the interaction of genome-wide SNP markers with a vast assortment of environmental variables and searching for SNPs controlling phenotypic variance (vQTL) using a large beef cattle dataset. We showed that GxE contribute 10%, 4%, and 3% of the phenotypic variance of birth weight, weaning weight, and yearling weight, respectively. GxE genome-wide association analysis (GWAA) detected a large number of GxE loci affecting growth traits, which the traditional GWAA did not detect, showing that functional loci may have non-additive genetic effects between genotype classes regardless of differences in genotypic means. We also showed that variance-heterogeneity GWAA can detect loci enriched with GxE effects without requiring prior knowledge of the interacting environmental factors. Functional annotation and pathway analysis of GxE genes revealed biological mechanisms by which cattle respond to changes in their environment, such as neural signaling, metabolic, hypoxia-induced, and immune system pathways. Knowledge of these pathways will be important as climate change becomes a burden on animal health and productivity. In addition, ecoregion-specific GxE SNPs detected in this study may play a crucial role in identifying resilient and adapted beef cattle across divergent environments.ConclusionsWe detected novel trait associations with large GxE effects for birth weight, weaning weight, and yearling weight. Functional annotation and pathway analysis uncovered genomic regions involved in response to environmental stimuli. We unraveled the relevance and complexity of the genetic basis of GxE underlying growth traits, providing new insights into how different environmental conditions interact with specific genes influencing adaptation and productivity in beef cattle and potentially across mammals


2021 ◽  
Vol 11 ◽  
Author(s):  
Zhengfu Zhou ◽  
Ziwei Zhang ◽  
Lihua Jia ◽  
Hongxia Qiu ◽  
Huiyue Guan ◽  
...  

Bread wheat is one of the most important crops worldwide, supplying approximately one-fifth of the daily protein and the calories for human consumption. Gluten aggregation properties play important roles in determining the processing quality of wheat (Triticum aestivum L.) products. Nevertheless, the genetic basis of gluten aggregation properties has not been reported so far. In this study, a recombinant inbred line (RIL) population derived from the cross between Luozhen No. 1 and Zhengyumai 9987 was used to identify quantitative trait loci (QTL) underlying gluten aggregation properties with GlutoPeak parameters. A linkage map was constructed based on 8,518 SNPs genotyped by specific length amplified fragment sequencing (SLAF-seq). A total of 33 additive QTLs on 14 chromosomes were detected by genome-wide composite interval mapping (GCIM), four of which accounted for more than 10% of the phenotypic variation across three environments. Two major QTL clusters were identified on chromosomes 1DS and 1DL. A premature termination of codon (PTC) mutation in the candidate gene (TraesCS1D02G009900) of the QTL cluster on 1DS was detected between Luozhen No. 1 and Zhengyumai 9987, which might be responsible for the difference in gluten aggregation properties between the two varieties. Subsequently, two KASP markers were designed based on SNPs in stringent linkage with the two major QTL clusters. Results of this study provide new insights into the genetic architecture of gluten aggregation properties in wheat, which are helpful for future improvement of the processing quality in wheat breeding.


Animals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 596 ◽  
Author(s):  
Fengwei Zhang ◽  
Kaixing Qu ◽  
Ningbo Chen ◽  
Quratulain Hanif ◽  
Yutang Jia ◽  
...  

We report genome characterization of three native Chinese cattle breeds discovering ~34.3 M SNPs and ~3.8 M InDels using whole genome resequencing. On average, 10.4 M SNPs were shared amongst the three cattle breeds, whereas, 3.0 M, 4.9 M and 5.8 M were specific to LQ, WN and WS breeds, respectively. Gene ontology (GO)analysis revealed four immune response-related GO terms were over represented in all samples, while two immune signaling pathways were significantly over-represented in WS cattle. Altogether, we found immune related genes (PGLYRP2, ROMO1, FYB2, CD46, TSC1) in the three cattle breeds. Our study provides insights into the genetic basis of Chinese indicine adaptation to the tropic and subtropical environment, and provides a valuable resource for further investigations of genetic characteristics of the three breeds.


2015 ◽  
Author(s):  
Wen Huang ◽  
Mary Anna Carbone ◽  
Michael Magwire ◽  
Jason Peiffer ◽  
Richard Lyman ◽  
...  

Understanding how DNA sequence variation is translated into variation for complex phenotypes has remained elusive, but is essential for predicting adaptive evolution, selecting agriculturally important animals and crops, and personalized medicine. Here, we quantified genome-wide variation in gene expression in the sequenced inbred lines of the Drosophila melanogaster Genetic Reference Panel (DGRP). We found that a substantial fraction of the Drosophila transcriptome is genetically variable and organized into modules of genetically correlated transcripts, which provide functional context for newly identified transcribed regions. We identified regulatory variants for the mean and variance of gene expression, the latter of which could often be explained by an epistatic model. Expression quantitative trait loci for the mean, but not the variance, of gene expression were concentrated near genes. This comprehensive characterization of population scale diversity of transcriptomes and its genetic basis in the DGRP is critically important for a systems understanding of quantitative trait variation.


2019 ◽  
Author(s):  
Yu-Fang Pei ◽  
Yao-Zhong Liu ◽  
Xiao-Lin Yang ◽  
Hong Zhang ◽  
Gui-Juan Feng ◽  
...  

AbstractLean body mass (LBM), an important physiological measure, has a strong genetic determination. To clarify its genetic basis, a large-scale genome-wide association study (GWAS) of appendicular lean mass (ALM) was conducted in 450,580 UK Biobank subjects. A total of 717 variants (p<5×10−9) from 561 loci were identified, which were replicated across genders (achieving p<5×10−5 in both genders). The identified variants explained ~11% phenotypic variance, accounting for one quarter of the total ~40% GWAS-attributable heritability. The identified variants were enriched in gene sets related to musculoskeletal and connective tissue development. Of interest are several genes, including ADAMTS3, PAM, SMAD3 and MEF2C, that either contain multiple significant variants or serve as the hub genes of the associated gene sets. Polygenic score prediction based on the associated variants was able to distinguish subjects of high from low ALM. Overall, our results offered significant findings on the genetic basis of lean mass through an extraordinarily large sample GWAS. The findings are important to not only lean mass per se but also other complex diseases, such as type 2 diabetes and fracture, as our Mendelian randomization analysis showed that ALM is a protective factor for these two diseases.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Zhengjie Chen ◽  
Dengguo Tang ◽  
Kun Hu ◽  
Lei Zhang ◽  
Yong Yin ◽  
...  

Abstract Background Teosinte ear bears single spikelet, whereas maize ear bears paired spikelets, doubling the number of grains in each cupulate during maize domestication. In the past 20 years, genetic analysis of single vs. paired spikelets (PEDS) has been stagnant. A better understanding of genetic basis of PEDS could help fine mapping of quantitative trait loci (QTL) and cloning of genes. Results In this study, the advanced mapping populations (BC3F2 and BC4F2) of maize × teosinte were developed by phenotypic recurrent selection. Four genomic regions associated with PEDS were detected using QTL-seq, located on 194.64–299.52 Mb, 0–162.80 Mb, 12.82–97.17 Mb, and 125.06–157.01 Mb of chromosomes 1, 3, 6, and 8, respectively. Five QTL for PEDS were identified in the regions of QTL-seq using traditional QTL mapping. Each QTL explained 1.12–38.05% of the phenotypic variance (PVE); notably, QTL qPEDS3.1 with the average PVE of 35.29% was identified in all tests. Moreover, 14 epistatic QTL were detected, with the total PVE of 47.57–66.81% in each test. The QTL qPEDS3.1 overlapped with, or was close to, one locus of 7 epistatic QTL. Near-isogenic lines (NILs) of QTL qPEDS1.1, qPEDS3.1, qPEDS6.1, and qPEDS8.1 were constructed. All individuals of NIL-qPEDS6.1(MT1) and NIL-qPEDS8.1(MT1) showed paired spikelets (PEDS = 0), but the flowering time was 7 days shorter in the NIL-qPEDS8.1(MT1). The ratio of plants with PEDS > 0 was low (1/18 to 3/18) in the NIL-qPEDS1.1(MT1) and NIL-qPEDS3.1(MT1), maybe due to the epistatic effect. Conclusion Our results suggested that major QTL, minor QTL, epistasis and photoperiod were associated with the variation of PEDS, which help us better understand the genetic basis of PEDS and provide a genetic resource for fine mapping of QTL.


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