Phylogeny and Biogeography of the Family Haemulidae Based on a Multigene Approach

Haemulids are one of the most ecologically and commercially important groups of near-shore fishes. They are very diverse, with 145 putative species belonging to 18 genera. The phylogenetic relationships of the genera within the haemulids, however, are uncertain and the limits and relationships with other percomorphs are undefined. Here, I present the first comprehensive phylogenetic hypothesis for the family based on a combined dataset of five genes (4731 bp; 16 genera, 56 species). Results show strong support for a monophyletic Haemulidae with the inclusion of the former inermiids. However, results of the analyses call into question the monophyly of a number of genera (e.g. Pomadasys). Furthermore, results show Haemulidae as sister to Lutjanidae, and Hapalogenys as outside the Haemulidae, based on a limited sampling of outgroups, and suggest further studies are needed that will incorporate a wider subset of taxa and more genes. I provide a phylogenetic hypothesis of the interfamilial relationships within percomorphs based on RAxML (Randomized Axelerated Maximum Likelihood) analysis of 23-gene dataset (1231 taxa) to determine sister groups of haemulids. This study presents the most comprehensive dataset, encompassing the major lineages within Percomorphaceae, and poses novel hypothesis regarding relationships of many groups. Results show haemulids are sister to Lutjanidae plus Caesionidae in a clade together with Callanthiidae, Malacanthidae, Pomacanthidae, Emmelichthyidae, Acanthuriformes, Monodactylidae, Sciaenidae, Chaetodontidae, and Leiognathidae; however, support for this group is weak. Further, I test the utility of mitogenomes (14 genera, 26 species; ~16,000 bp) and multi-locus data (22 genes; 19 genera, 82 species) to infer interrelationships within the haemulids in order to address what might have been the limits of the second chapter using RAxML analyses. Similarly, the family Haemulidae and subfamilies Plectorhinchinae and Haemulinae were recovered as monophyletic. Although improvement in nodal support is evident using both datasets, resolution at the species level using the mitogenomes is not possible due to limited availability of mitogenomes for the haemulids. Nevertheless, analyses revealed a possible radiation for the haemulids originating from the Old World to the New World. The more inclusive 22-gene dataset provided resolution for the interrelationships within the family, and better explained the non-monophyly of the genus Pomadasys

Quantitative Trait Loci for Freezing Tolerance in a Lowland x Upland Switchgrass Population

Low-temperature related abiotic stress is an important factor affecting winter survival in lowland switchgrass when grown in northern latitudes in the United States. A better understanding of the genetic architecture of freezing tolerance in switchgrass will aid the development of lowland switchgrass cultivars with improved winter survival. The objectives of this study were to conduct a freezing tolerance assessment, generate a genetic map using single nucleotide polymorphism (SNP) markers, and identify QTL (quantitative trait loci) associated with freezing tolerance in a lowland × upland switchgrass population. A pseudo-F2 mapping population was generated from an initial cross between the lowland population Ellsworth and the upland cultivar Summer. The segregating progenies were screened for freezing tolerance in a controlled-environment facility. Two clonal replicates of each genotype were tested at six different treatment temperatures ranging from −15 to −5°C at an interval of 2°C for two time periods. Tiller emergence (days) and tiller number were recorded following the recovery of each genotype with the hypothesis that upland genotype is the source for higher tiller number and early tiller emergence. Survivorship of the pseudo-F2 population ranged from 89% at −5°C to 5% at −15°C with an average LT50 of −9.7°C. Genotype had a significant effect on all traits except tiller number at −15°C. A linkage map was constructed from bi-allelic single nucleotide polymorphism markers generated using exome capture sequencing. The final map consisted of 1618 markers and 2626 cM, with an average inter-marker distance of 1.8 cM. Six significant QTL were identified, one each on chromosomes 1K, 5K, 5N, 6K, 6N, and 9K, for the following traits: tiller number, tiller emergence days and LT50. A comparative genomics study revealed important freezing tolerance genes/proteins, such as COR47, DREB2B, zinc finger-CCCH, WRKY, GIGANTEA, HSP70, and NRT2, among others that reside within the 1.5 LOD confidence interval of the identified QTL

Genomic Prediction for Winter Survival of Lowland Switchgrass in the Northern USA

The lowland ecotype of switchgrass has generated considerable interest because of its higher biomass yield and late flowering characteristics compared to the upland ecotype. However, lowland ecotypes planted in northern latitudes exhibit very low winter survival. Implementation of genomic selection could potentially enhance switchgrass breeding for winter survival by reducing generation time while eliminating the dependence on weather. The objectives of this study were to assess the potential of genomic selection for winter survival in lowland switchgrass by combining multiple populations in the training set and applying the selected model in two independent testing datasets for validation. Marker data were generated using exome capture sequencing. Validation was conducted using (1) indirect indicators of winter adaptation based on geographic and climatic variables of accessions from different source locations and (2) winter survival estimates of the phenotype. The prediction accuracies were significantly higher when the training dataset comprising all populations was used in fivefold cross validation but its application was not useful in the independent validation dataset. Nevertheless, modeling for population heterogeneity improved the prediction accuracy to some extent but the genetic relationship between the training and validation populations was found to be more influential. The predicted winter survival of lowland switchgrass indicated latitudinal and longitudinal variability, with the northeast USA the region for most cold tolerant lowland populations. Our results suggested that GS could provide valuable opportunities for improving winter survival and accelerate the lowland switchgrass breeding programs toward the development of cold tolerant cultivars suitable for northern latitudes

Discovery of genomic variants associated with genebank historical traits for rice improvement: SNP and indel data, phenotypic data, and GWAS results

This dataset provides supporting information for Sanciangco et al (submitted) consisting of: A) file list, tables of phenotypes for quantitative and categorical traits and trait descriptions, and tables of SNP/indel numbers for Filtered, LD-pruned and subpopulation datasets (7 files named as "00_*"); B) plink files for Filtered and LD-pruned SNP/indel datasets for all genotypes and for indica, japonica and aus subsets (15 fIles named as "01_*"); C) EMMAX results on Filtered dataset for 12 quantitative traits on All, Aus, Indica, and Japonica genotypes and corresponding Manhattan and QQ plots (144 files named as "0[2345]_*"); D) EMMAX results on LD-pruned dataset for 12 quantitative traits on All, Aus, Indica, and Japonica genotypes and corresponding Manhattan and QQ plots (72 files named as "0[6789]_*"); E) EMMAX results on LD-pruned dataset for 20 categorical traits treated as numeric on All genotypes and corresponding Manhattan and Q-Q plots (60 files named as "10_*"); F) Anova results obtained on numerically transformed LD-pruned dataset for 20 categorical traits on All genotypes and corresponding Manhattan plots (40 files named as "11_*")

Genome-Wide Association Study in Pseudo-F2 Populations of Switchgrass Identifies Genetic Loci Affecting Heading and Anthesis Dates

Switchgrass (Panicum virgatum) is a native prairie grass and valuable bio-energy crop. The physiological change from juvenile to reproductive adult can draw important resources away from growth into producing reproductive structures, thereby limiting the growth potential of early flowering plants. Delaying the flowering of switchgrass is one approach by which to increase total biomass. The objective of this research was to identify genetic variants and candidate genes for controlling heading and anthesis in segregating switchgrass populations. Four pseudo-F2 populations (two pairs of reciprocal crosses) were developed from lowland (late flowering) and upland (early flowering) ecotypes, and heading and anthesis dates of these populations were collected in Lafayette, IN and DeKalb, IL in 2015 and 2016. Across 2 years, there was a 34- and 73-day difference in heading and a 52- and 75-day difference in anthesis at the Lafayette and DeKalb locations, respectively. A total of 37,901 single nucleotide polymorphisms obtained by exome capture sequencing of the populations were used in a genome-wide association study (GWAS) that identified five significant signals at three loci for heading and two loci for anthesis. Among them, a homolog of FLOWERING LOCUS T on chromosome 5b associated with heading date was identified at the Lafayette location across 2 years. A homolog of ARABIDOPSIS PSEUDO-RESPONSE REGULATOR 5, a light modulator in the circadian clock associated with heading date was detected on chromosome 8a across locations and years. These results demonstrate that genetic variants related to floral development could lend themselves to a long-term goal of developing late flowering varieties of switchgrass with high biomass yield

Extensive Genetic Diversity is Present within North American Switchgrass Germplasm.

Switchgrass ( is a perennial native North American grass present in two ecotypes: upland, found primarily in the northern range of switchgrass habitats, and lowland, found largely in the southern reaches of switchgrass habitats. Previous studies focused on a diversity panel of primarily northern switchgrass, so to expand our knowledge of genetic diversity in a broader set of North American switchgrass, exome capture sequence data were generated for 632 additional, primarily lowland individuals. In total, over 37 million single nucleotide polymorphisms (SNPs) were identified and a set of 1.9 million high-confidence SNPs were obtained from 1169 individuals from 140 populations (67 upland, 65 lowland, 8 admixed) were used in downstream analyses of genetic diversity and population structure. Seven separate population groups were identified with moderate genetic differentiation [mean fixation index (Fst) estimate of 0.06] between the lowland and the upland populations. Ecotype-specific and population-specific SNPs were identified for use in germplasm evaluations. Relative to rice ( L.), maize ( L.), soybean [ (L.) Merr.], and Gaertn., analyses of nucleotide diversity revealed a high degree of genetic diversity (0.0135) across all individuals, consistent with the outcrossing mode of reproduction and the polyploidy of switchgrass. This study supports the hypothesis that repeated glaciation events, ploidy barriers, and restricted gene flow caused by flowering time differences have resulted in distinct gene pools across ecotypes and geographic regions. These data provide a resource to associate alleles with traits of interest for forage, restoration, and biofuel feedstock efforts in switchgrass

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Data from: Extensive genetic diversity is present within North American switchgrass germplasm

Switchgrass (Panicum virgatum L.) is a perennial native North American grass present in two ecotypes: upland, found primarily in the northern range of switchgrass habitats, and lowland, found largely in the southern reaches of switchgrass habitats. Previous studies focused on a diversity panel of primarily northern switchgrass, so to expand our knowledge of genetic diversity in a broader set of North American switchgrass, exome capture sequence data were generated for 632 additional, primarily lowland individuals. In total, over 37 million single nucleotide polymorphisms (SNPs) were identified and a set of 1.9 million high-confidence SNPs were obtained from 1169 individuals from 140 populations (67 upland, 65 lowland, 8 admixed) were used in downstream analyses of genetic diversity and population structure. Seven separate population groups were identified with moderate genetic differentiation [mean fixation index (Fst) estimate of 0.06] between the lowland and the upland populations. Ecotype-specific and population-specific SNPs were identified for use in germplasm evaluations. Relative to rice (Oryza sativa L.), maize (Zea mays L.), soybean [Glycine max (L.) Merr.], and Medicago truncatula Gaertn., analyses of nucleotide diversity revealed a high degree of genetic diversity (0.0135) across all individuals, consistent with the outcrossing mode of reproduction and the polyploidy of switchgrass. This study supports the hypothesis that repeated glaciation events, ploidy barriers, and restricted gene flow caused by flowering time differences have resulted in distinct gene pools across ecotypes and geographic regions. These data provide a resource to associate alleles with traits of interest for forage, restoration, and biofuel feedstock efforts in switchgrass

Extensive Genetic Diversity is Present within North American Switchgrass Germplasm

Switchgrass ( is a perennial native North American grass present in two ecotypes: upland, found primarily in the northern range of switchgrass habitats, and lowland, found largely in the southern reaches of switchgrass habitats. Previous studies focused on a diversity panel of primarily northern switchgrass, so to expand our knowledge of genetic diversity in a broader set of North American switchgrass, exome capture sequence data were generated for 632 additional, primarily lowland individuals. In total, over 37 million single nucleotide polymorphisms (SNPs) were identified and a set of 1.9 million high-confidence SNPs were obtained from 1169 individuals from 140 populations (67 upland, 65 lowland, 8 admixed) were used in downstream analyses of genetic diversity and population structure. Seven separate population groups were identified with moderate genetic differentiation [mean fixation index (Fst) estimate of 0.06] between the lowland and the upland populations. Ecotype-specific and population-specific SNPs were identified for use in germplasm evaluations. Relative to rice ( L.), maize ( L.), soybean [ (L.) Merr.], and Gaertn., analyses of nucleotide diversity revealed a high degree of genetic diversity (0.0135) across all individuals, consistent with the outcrossing mode of reproduction and the polyploidy of switchgrass. This study supports the hypothesis that repeated glaciation events, ploidy barriers, and restricted gene flow caused by flowering time differences have resulted in distinct gene pools across ecotypes and geographic regions. These data provide a resource to associate alleles with traits of interest for forage, restoration, and biofuel feedstock efforts in switchgrass