Influence of the PCR artifacts on the genotyping efficiency by the microsatellite loci using native polyacrylamide gel electrophoresis

Genetic diversity and population structure of soybean (Glycine max (L.) Merril) germplasm

Soybean (Glycine max (L.) Merril) is a significant legume crop for oil and protein. However, its yield in Africa is less than half the global average resulting in low production, which is inadequate for satisfying the continent's needs. To address this disparity in productivity, it is crucial to develop new high-yielding cultivars by utilizing the genetic diversity of existing germplasms. Consequently, the genetic diversity and population structure of various soybean accessions were evaluated in this study. To achieve this objective, a collection of 147 soybean accessions was genotyped using the Diversity Array Technology Sequencing method, enabling high-throughput analysis of 7,083 high-quality single-nucleotide polymorphisms (SNPs) distributed across the soybean genome. The average values observed for polymorphism information content (PIC), minor allele frequency, expected heterozygosity and observed heterozygosity were 0.277, 0.254, 0.344, and 0.110, respectively. The soybean genotypes were categorized into four groups on the basis of model-based population structure, principal component analysis, and discriminant analysis of the principal component. Alternatively, hierarchical clustering was used to organize the accessions into three distinct clusters. Analysis of molecular variance indicated that the genetic variance (77%) within the populations exceeded the variance (23%) among them. The insights gained from this study will assist breeders in selecting parental lines for genetic recombination. The present study demonstrates that soybean improvement is viable within the IITA breeding program, and its outcome will help to optimize the genetic enhancement of soybeans.

Application of PCR-HRM method for microsatellite polymorphism genotyping in the LDHA gene of pigeons (Columba livia)

High-resolution melting (HRM) is a post-PCR method that allows to discriminate genotypes based on fluorescence changes during the melting phase. HRM is used to detect mutations or polymorphisms (e.g. microsatellites, SNPs, indels). Here, the (TTTAT)_3-5 microsatellite polymorphism within intron 6 of the LDHA gene in pigeons was analysed using the HRM method. Individuals (123 homing pigeons) were genotyped using conventional PCR. Birds were classified into groups based on genotype type and the results were tested by qPCR-HRM and verified using sequencing. Based on the evaluated protocol, five genotypes were identified that vary in the number of TTTAT repeat units (3/3, 4/4, 3/4, 4/5, and 5/5). Sequencing have confirmed the results obtained with qPCR-HRM and verified that HRM is a suitable method for identification of three-allele microsatellite polymorphisms. It can be concluded that the high-resolution melting (HRM) method can be effectively used for rapid (one-step) discrimination of the (TTTAT)_3-5 microsatellite polymorphism in the pigeon’s LDHA gene.

Molecular genetic diversity and population structure analyses of rutabaga accessions from Nordic countries as revealed by single nucleotide polymorphism markers

Background

Rutabaga or swede (Brassica napus ssp. napobrassica (L.) Hanelt) varies in root and leaf shape and colour, flesh colour, foliage growth habits, maturity date, seed quality parameters, disease resistance and other traits. Despite these morphological differences, no in-depth molecular analyses of genetic diversity have been conducted in this crop. Understanding this diversity is important for conservation and broadening the use of this resource.

Results

This study investigated the genetic diversity within and among 124 rutabaga accessions from five Nordic countries (Norway, Sweden, Finland, Denmark and Iceland) using a 15 K single nucleotide polymorphism (SNP) Brassica array. After excluding markers that did not amplify genomic DNA, monomorphic and low coverage site markers, the accessions were analyzedwith 6861 SNP markers. Allelic frequency statistics, including polymorphism information content (PIC), minor allele frequency (MAF) and mean expected heterozygosity (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \overline{H} $$\end{document}H¯e) and population differentiation statistics such as Wright’s F-statistics (F_ST) and analysis of molecular variance (AMOVA) indicated that the rutabaga accessions from Norway, Sweden, Finland and Denmark were not genetically different from each other. In contrast, accessions from these countries were significantly different from the accessions from Iceland (P < 0.05). Bayesian analysis with the software STRUCTURE placed 66.9% of the rutabaga accessions into three to four clusters, while the remaining 33.1% constituted admixtures. Three multivariate analyses: principal coordinate analysis (PCoA), the unweighted pair group method with arithmetic mean (UPGMA) and neighbour-joining (NJ) clustering methods grouped the 124 accessions into four to six subgroups.

Conclusion

Overall, the correlation of the accessions with their geographic origin was very low, except for the accessions from Iceland. Thus, Icelandic rutabaga accessions can offer valuable germplasm for crop improvement.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-021-07762-4.

Patterns of PCR Amplification Artifacts of the Fungal Barcode Marker in a Hybrid Mushroom

The polymerase chain reaction (PCR) is widely used in modern biology and medicine. However, PCR artifacts can complicate the interpretation of PCR-based results. The internal transcribed spacer (ITS) region of the ribosomal RNA gene cluster is the consensus fungal barcode marker and suspected PCR artifacts have been reported in many studies, especially for the analyses of environmental fungal samples. At present, the patterns of PCR artifacts in the whole fungal ITS region (ITS1+5.8S+ITS2) are not known. In this study, we analyzed the error rates of PCR at three template complexity levels using the divergent copies of ITS from the mushroom Agaricus subrufescens. Our results showed that PCR using the Phusion^® High-Fidelity DNA Polymerase has a per nucleotide error rate of about 4 × 10^–6 per replication. Among the detected mutations, transitions were much more frequent than transversions, insertions, and deletions. When divergent alleles were mixed as templates in the same reaction, a significant proportion (∼30%) of recombinant molecules were detected. The in vitro mixed-template results were comparable to those obtained from using the genomic DNA of the original mushroom specimen as template. Our results indicate that caution should be in place when interpreting ITS sequences from individual fungal specimens, especially those containing divergent ITS copies. Similar results could also happen to PCR-based analyses of other multicopy DNA fragments as well as single-copy DNA sequences with divergent alleles in diploid organisms.

Analysis of the genetic structure of a population of Lebedyn cattle by microsatellite markers

Microsatellites – a separate class of molecular genetic markers, are widely used for the study of genetic variability, in particular in populations of animals bred by artificial selection under the influence of microevolutionary processes. The object of study is the gene pool of a population of animals of the Lebedyn cattle breed, which is under threat of extinction. The sample comprised 30 individuals from the farm "Komyshans'ke" in Sumy region. The analysis of population genetic structure was performed using 10 microsatellite loci recommended by FAO-ISAG: ETH225, BM2113, ETH3, BM1818, BM1824, ILSTS006, INRA023, TAGLA053, TAGLA12, ETH10. Amplification products were separated in polyacrylamide gels of different concentrations (5–8%), both native and denaturing. All studied loci were polymorphic. The number of detected alleles per locus ranged from 4 to 8 (on average 5 alleles per locus), the size of which ranged from 115 bp (ETH3) to 307 bp (ILSTS006). The majority of the investigated loci (except ETH3) belonged to valuable informative markers (PIC > 0.5). The most polymorphic TGLA053 (8 alleles), BM2113 (6) and ETH3 (6) loci have been identified. In general, the minimum number of alleles (4) was fixed in 50% loci. The main population genetic parameters for the studied loci have been calculated. The highest values of heterozygosity (He), and effective number of alleles (ne) was characterized for loci BM2113, ILSTS006, TGLA053 and ETH225. With the exception of ETH3 and VM1818 loci, the experimental group of animals is in a state of genetic equilibrium. The average value of the Wright fixation index indicates a tendency to increase in the number of homozygous individuals (inbreeding). Comparative analysis of genetic structure of breeds that have a common origin (Lebedyn (PJSC "Mykhaylivka"), Ukrainian grey (DPDG "Polyvanivka"), Red steppe (DPPR "Stepne"), etc.) has been carried out. The obtained results give grounds to assert that in the experimental population of the Lebedyn breed there are processes that lead to a decrease in genetic diversity. In order to overcome the negative effects of artificial reproduction in the gene pool of small populations of cattle, which include Lebedyn cattle, it is appropriate to use microsatellite markers in the selection and breeding work.

Intron length polymorphism of β-tubulin genes of Aegilops biuncialis Vis

Intron-specific DNA polymorphism is present among plant β-tubulin gene family members and is considered to be one of the molecular markers based on the difference of tubulin introns length assayed both separately (TBP: 1st intron) or in combination (h-TBP: 1st and 2nd introns). These two approaches are possibly useful for wheat breeding programs, since TBP and h-TBP help to differentiate between the accessions of Aegilops biuncialis Vis., a wild relative of wheat. PCR-derived polymorphic fragments were resolved by PAGE electrophoresis. The length of amplicons varied significantly (395-3900 bp for TBP and 466-3440 bp for h-TBP), while the numbers of polymorphic bands were 21 for TBP and 23 for h-TBP, respectively. PIC mean value was circa 0.3. Dendrograms constructed on the basis of the Nei and Li coefficient with the high bootstrap support reveal a similar order of hierarchy for the samples analyzed using both methods. Thus, both techniques uncover DNA polymorphism level sufficiently high to distinguish different accessions of Ae. biuncialis Vis.