Development And Identification of 131 SNP Markers In Sthenoteuthis Pteropus (Steenstrup)

The orangeback flying squid, Sthenoteuthis pteropus, is a species of significant potential value that is widely distributed in the tropical and temperate waters of the Atlantic Ocean. There have been no reports of the population genetics and effective molecular markers for this species due to a lack of reliable information regarding its genetic structure and its many individual differences, as well as its complex and changeable life history. Therefore, the development of auxiliary molecular markers would contribute to the development, sustainable utilization, and protection of the species. In this study, 131 novel single nucleotide polymorphism (SNP) markers were developed by double digest restriction-site associated DNA sequencing (dd-RAD). The observed heterozygosity (Ho) and expected heterozygosity (He) ranged from 0.00 to 0.80 and 0.18 to 0.50, respectively. The polymorphism information content (PIC) value ranged from 0.18 to 0.50. None of the marker locations significantly deviated from the Hardy-Weinberg equilibrium (p >0.05) after a Bonferroni correction. These polymorphic SNPs will be important in the further analysis of the population heredity of S. pteropus and its scientific management.

Diversity And Population Structure of Nordic Potato Cultivars and Breeding Clones Grown Under Long Daylength in Europe

The genetic diversity and population structure of breeding germplasm is central knowledge for crop improvement. To gain insight into the genetic potential of the germplasm used for potato breeding in a Nordic breeding program as well as the collections from the Nordic genebank (NordGen), 133 potato genotypes were genotyped using the Infinium Illumina 20K SNP array. After SNP filtering, 11 610 polymorphic SNPs were included in the analysis. In addition, data from three important breeding traits – percent dry matter and uniformity of tuber shape and eye – were scored to measure the variation be-tween groups. The genetic diversity among the genotypes was estimated using principal coordinate analysis based on the genetic distance between individuals, as well as by using the software STRUC-TURE. Both methods suggest that the collected breeding material and the germplasm from the gene-bank are closely related, with a low degree of population structure between the groups. The phenotypic distribution among the genotypes revealed significant differences, especially between farmer’s cultivars and released cultivars and breeding clones. The percent heterozygosity was similar between the groups, with a mean average of 58–60%. Overall, the breeding germplasm and the collection of genotypes from the Nordic gene bank seems to be closely related with similar genetic background. This gains insight that the genetic potential of available Nordic potato breeding germplasm is low, and for genetic hybridi-zation purposes, genotypes from outside the Nordic region should be employed.

QTL and candidate gene identification of the node of the first fruiting branch (NFFB) by QTL-seq in upland cotton (Gossypium hirsutum L.)

Background The node of the first fruiting branch (NFFB) is an important precocious trait in cotton. Many studies have been conducted on the localization of quantitative trait loci (QTLs) and genes related to fiber quality and yield, but there has been little attention to traits related to early maturity, especially the NFFB, in cotton. Results To identify the QTL associated with the NFFB in cotton, a BC4F2 population comprising 278 individual plants was constructed. The parents and two DNA bulks for high and low NFFB were whole genome sequenced, and 243.8 Gb of clean nucleotide data were generated. A total of 449,302 polymorphic SNPs and 135,353 Indels between two bulks were identified for QTL-seq. Seventeen QTLs were detected and localized on 11 chromosomes in the cotton genome, among which two QTLs (qNFFB-Dt2–1 and qNFFB-Dt3–3) were located in hotspots. Two candidate genes (GhAPL and GhHDA5) related to the NFFB were identified using quantitative real-time PCR (qRT-PCR) and virus-induced gene silencing (VIGS) experiments in this study. Both genes exhibited higher expression levels in the early-maturing cotton material RIL182 during flower bud differentiation, and the silencing of GhAPL and GhHDA5 delayed the flowering time and increased the NFFB compared to those of VA plants in cotton. Conclusions Our study preliminarily found that GhAPL and GhHDA5 are related to the early maturity in cotton. The findings provide a basis for the further functional verification of candidate genes related to the NFFB and contribute to the study of early maturity in cotton.

Population Structure and Genetic Diversity of Two-Rowed Barley Accessions from Kazakhstan Based on SNP Genotyping Data

The genetic relationship and population structure of two-rowed barley accessions from Kazakhstan were assessed using single-nucleotide polymorphism (SNP) markers. Two different approaches were employed in the analysis: (1) the accessions from Kazakhstan were compared with barley samples from six different regions around the world using 1955 polymorphic SNPs, and (2) 94 accessions collected from six breeding programs from Kazakhstan were studied using 5636 polymorphic SNPs using a 9K Illumina Infinium assay. In the first approach, the neighbor-joining tree showed that the majority of the accessions from Kazakhstan were grouped in a separate subcluster with a common ancestral node; there was a sister subcluster that comprised mainly barley samples that originated in Europe. The Pearson’s correlation analysis suggested that Kazakh accessions were genetically close to samples from Africa and Europe. In the second approach, the application of the STRUCTURE package using 5636 polymorphic SNPs suggested that Kazakh barley samples consisted of five subclusters in three major clusters. The principal coordinate analysis plot showed that, among six breeding origins in Kazakhstan, the Krasnovodopad (KV) and Karaganda (KA) samples were the most distant groups. The assessment of the pedigrees in the KV and KA samples showed that the hybridization schemes in these breeding stations heavily used accessions from Ethiopia and Ukraine, respectively. The comparative analysis of the KV and KA samples allowed us to identify 214 SNPs with opposite allele frequencies that were tightly linked to 60 genes/gene blocks associated with plant adaptation traits, such as the heading date and plant height. The identified SNP markers can be efficiently used in studies of barley adaptation and deployed in breeding projects to develop new competitive cultivars.

Development and Characterization of 135 SNP Markers in Chiton Acanthochitona Rubrolineatus

Acanthochitona rubrolineatus (Lischke, 1873) (Polyplacophora, Neoloricata, Cryptoplacidae) is an important species widely distributed in the middle and low tide zone of coastal intertidal zone along the China Sea coast. In recent years, the serious pollution of seawater has caused a sharp decline in the number of wild populations of A. rubrolineatus. Lacking of effective molecular markers limits the effective protection and management of this species. Studies for the isolation and characterization of 135 A. rubrolineatus SNPs markers were carried out. The frequency of minor allele ranges from 0.0125 to 0.5000. The observed heterozygosity and expected heterozygosity are 0.0000-0.9750, 0.0731-0.6696, respectively. The inbreeding value varies from -0.2902 to 0.9966. Among them, there are 27 sites markablely differently from Hardy-Weinberg equilibrium (P < 0.05). The study of the polymorphic SNPs will provide a therotical basis for further analysis of population genetic analysis on A. rubrolineatus.

Development and Characterization of 177 SNP Markers in The Mud Shrimp Upogebia Major

The mud shrimp Upogebia major (De Haan, 1841) (Crustacea, Decapoda, Gebiidea) is an important species widely distributed in coastal shallow waters. As an active initiation species, it has contributed significantly to the maintenance of coastal benthic biodiversity. However, there is still a lack of effective molecular markers to effectively protect and manage this species. In this study, we used the DNeasy Blood & Tissue kit to extract DNA and Illumina HiSeq 4000 sequencing technology to obtain SNP marker resources. 177 single nucleotide polymorphism (SNP) markers were developed and characterized in U. major. The minor allele frequency raged from 0.0500 to 0.5000. The observed heterozygosity and expected heterozygosity ranged from 0.0333 to 0.9000 and from 0.0966 to 0.5085, respectively. Polymorphic information content ranged from 0.0905 to 0.3750. The inbreeding coefficient values varied from − 0.2902 to 0.5968. Seventeen loci showed significant deviations from the Hardy-Weinberg equilibrium (P < 0.05). The polymorphic SNPs will be helpful for the further population genetic analysis and natural resource conservation of U. major.

Parentage Analysis in Giant Grouper (Epinephelus lanceolatus) Using Microsatellite and SNP Markers from Genotyping-by-Sequencing Data

Pedigree information is necessary for the maintenance of diversity for wild and captive populations. Accurate pedigree is determined by molecular marker-based parentage analysis, which may be influenced by the polymorphism and number of markers, integrity of samples, relatedness of parents, or different analysis programs. Here, we described the first development of 208 single nucleotide polymorphisms (SNPs) and 11 microsatellites for giant grouper (Epinephelus lanceolatus) taking advantage of Genotyping-by-sequencing (GBS), and compared the power of SNPs and microsatellites for parentage and relatedness analysis, based on a mixed family composed of 4 candidate females, 4 candidate males and 289 offspring. CERVUS, PAPA and COLONY were used for mutually verification. We found that SNPs had a better potential for relatedness estimation, exclusion of non-parentage and individual identification than microsatellites, and > 98% accuracy of parentage assignment could be achieved by 100 polymorphic SNPs (MAF cut-off < 0.4) or 10 polymorphic microsatellites (mean Ho = 0.821, mean PIC = 0.651). This study provides a reference for the development of molecular markers for parentage analysis taking advantage of next-generation sequencing, and contributes to the molecular breeding, fishery management and population conservation.

Genetic Mapping And Genomic Prediction For Northern Corn Leaf Blight (Exserohilum Turcicum (Pass.) Leonard And Suggs) Resistance

Background: Northern corn leaf blight (NCLB) of maize caused by Exserohilum turcicum is a serious foliar disease. Resistance to NCLB is complexly inherited and the highly significant genotype x environment interaction effect makes selection of resistant genotypes difficult through conventional breeding methods. Hence an attempt was made to identify the genomic regions associated with NCLB resistance and perform genomic selection (GS) in two F2:3 populations derived from the crosses CM212 × MAI172 (Population-1) and CM202 × SKV50 (Population-2). Results: Two populations, each comprising of 366 progenies, were phenotyped at three different locations in the disease screening nurseries. Linkage analysis using 297 polymorphic SNPs in Population-1 and 290 polymorphic SNPs in Population-2 revealed 10 linkage groups spanning 3623.88cM and 4261.92cM with an average distance of 12.40 cM and 14.9 cM, respectively. Location-wise and pooled data across locations indicated that QTL expression was population and environment specific. The genomic prediction accuracies of 0.83 and 0.79 were achieved for NCLB Population 1 and Population 2, respectively. The resistant progenies from both populations were advanced to derive inbred lines and crossed with four different testers in line x tester mating design to test for their combining ability. High overall general combining ability was exhibited by 21 inbred lines. Among crosses 48 % were assigned high overall specific combining ability status. Out of 136 single crosses, seven recorded significant positive standard heterosis over the best check for grain yield. The clustering pattern of inbred lines developed from the two populations revealed high molecular diversity. Conclusions: In this study, comparatively better genomic prediction accuracies were achieved for NCLB and the worth of F3 progenies with high genomic predictions was proved by advancing them to derive inbred lines and establishing their higher combining ability for yield and yield related traits.

Genetic diversity and population structure among indigenous and imported goat breeds in Kenya

Population structure and relationship information among goats is critical for genetic improvement, utilization, and conservation. This study explored population structure and level of introgression among four goat breeds in Kenya: the indigenous Galla (n = 12) and three imported breeds, the Alpine (n = 29), Toggenburg (n = 31), and Saanen (n = 24). Genetic diversity was analyzed using four indices (polymorphic SNPs, mean allele frequency, observed and expected heterozygosity and inbreeding coefficient) within each breed. Population structure assessed using model-based clustering (ADMIXTURE) revealed four breeds according to their geographic regions in Kenya. Kenyan Alpine goats were the most admixed breed with about 10 % of its genome derived from Galla, 10 % and 6 % from Saanen and Toggenburg respectively. The association of Galla with other breeds was anticipated since the Galla breed was used as the founder population for crossbreeding with Saanen, Alpine and Toggenburg breeds. The relationship information evaluated by computing Reynolds genetic distance revealed five distinctive clusters: Alpine, Galla, Saanen, Toggenburg and some mixture of Alpine and Toggenburg. Saanen and Galla breeds seem to be the most genetically distinct among the sampled populations. The genetic variation among the goat populations observed will provide a good opportunity for sustainable utilization, conservation, and future genetic resource improvement programmes in goat breeds in Kenya.

Isolation And Characterization Of 45 SNP Markers In Triplophysa Tenuis

Triplophysa tenuis is an endemic species to China, which mainly distributed in Xinjiang and Gansu province. Effective conservation and management of this species is limited by insufficient molecular markers. In the present study, we reported the isolation and characterization of 45 SNP markers in T. tenuis. The minor allele frequency ranged from 0.046 to 0.500, and the observed and expected heterozygosities ranged from 0.061 to 0.667 and 0.088 to 0.508, respectively. Polymorphic information content ranged from 0.083 to 0.375. Among these SNPs, three loci showed significant departures from the Hardy–Weinberg equilibrium. The novel polymorphic SNPs will be helpful for the future study on genetic management and population conservation for this species.