Polymorphism Information Content Research Articles

Genome-wide identification of SSR markers for Curcuma alismatifolia Gagnep., and their potential for wider application in this genus

The genus Curcuma, containing over 120 species, have considerable ornamental, edible and medicinal value. Due to the persistent lack of efficient genomic SSR markers, the conservation and identification of Curcuma genetic resources have faced substantial challenges in practical applications. To date, there are few systematic researches on whole-genome mining of SSR locus in the genus Curcuma. Herein, we performed the first deep identification of genome-wide SSR markers based on the whole-genome data of C. alismatifolia. A total of 257,032 SSR loci were identified with an average density of 216.1–367.3 SSRs/Mb within each chromosome. Mononucleotide repeat loci were most abundant, accounting for 55.1 % of all SSRs, with dinucleotide and trinucleotide repeats accounting for 22.6 % and 20.3 %, respectively. Moreover, 38 polymorphic genomic SSRs (g-SSR) were screened from the synthesized 280 primer pairs, with an average allele number (Na) and polymorphic information content (PIC) of 15.342 and 0.775 per locus, respectively. These markers had excellent cross-species transferability with an overall efficiency of 97.5 % in 21 Curcuma species. According to the cluster and structure analyses, the 178 Curcuma accessions were devided into three major clades correspongding to their origins, hybrid affinities and use values. Finally, a total of 66 Curcuma core collections were preserved, with no significant difference in genetic diversity between the core and entire collections by the t-test. A combination of numbers and letters was employed to establish DNA barcodes for 66 core collections. This study provides valuable molecular markers for wild-collection and conservation, genetic diversity analysis and marker-assisted selection breeding of Curcuma.

A comparative study of population structure and genetic diversity of commercial and indigenous chickens from different agro-ecological zones in Ghana using SilicoDArT and SNP markers

Chicken production, both in the local and commercial sectors, contributes significantly to human livelihood and food security. Precise use of diverse genetic resources is primary in breeding programs. The study analyzed the genetic diversity and population structure of commercial chickens and indigenous chicken ecotypes from three different agro-ecological zones (Semi-Deciduous Rainforest Zone, Guinea Savannah, and Coastal Savannah) using SilicoDArT and SNP markers, utilizing whole-genome sequencing and phenotypic data. Phenotypic data were collected from 72 indigenous chicken ecotypes across the three AEZs, and 32 commercial birds kept at the Kwame Nkrumah University of Science and Technology (KNUST). DNA samples used for sequencing were obtained from 88 chickens (62 indigenous chicken ecotypes and 26 commercial chickens). A total of 54,995 SilicoDArT and 85,396 SNPs markers were generated from DArTseq genotyping. After filtering, 44,784 SilicoDArT and 58,353 SNP were used for genetic diversity and population structure analysis. Both markers showed high reproducibility and call rate. Polymorphic information content (PIC) values ranged from 0.00 to 0.50, while ≥ 50 % showed PIC values more than the median. Furthermore, we obtained FST values, Nei’s genetic distance, dendrogram analysis, and principal component analysis (PCA) of commercial and indigenous chickens. The FST and Nei’s genetic distance showed that there is high genetic diversity between the commercial chickens and the indigenous chicken ecotypes. However, there was low genetic diversity among the indigenous chicken ecotypes. The PCA analysis indicated a clear separation between the commercial and indigenous chicken ecotypes, while no clear separation was observed between the indigenous chicken ecotypes. The phenotypic data and the dendrogram indicated that naked and frizzle genes do not markedly alter the genetics of indigenous and commercial birds, and their influence on economic traits may be solely determined by the prevailing environmental conditions. The results indicate that there is high genetic differentiation between commercial and indigenous chickens based on SilicoDArT and SNP markers. The indigenous chickens from the agro-ecological zones have low genetic diversity and might have a common origin. Naked neck and frizzle genes do not markedly alter the genetic performance of birds in terms of economic traits. Therefore, the superiority of birds carrying these genes in economic traits may be solely due to environmental variation.

Inter and intra population genetic variability in ducks under conservation programs

This study focuses on estimation of the inter and intra population genetic variability of 6 duck populations. Microsatellite loci were used to assess the genetic variation and population structure of 6 duck populations under a conservation program in Poland. DNA polymorphism was assessed using 24 microsatellite markers and 50 individuals from each population. Polymorphism information content (PIC), heterozygosity with 2 estimators of genetic differentiation (FST and GST), and Nei's standard genetic distance were calculated. The results showed that these 6 endangered duck populations showed high genetic polymorphism. Observed heterozygosity within populations ranged from 0.14 to 0.83, with the average value of 0.58. PIC within populations ranged from 0.038 (P-8 and P-9 lines) to 0.89 (LsA line). Average number of alleles in the studied populations ranged from 4.5 (KhO-1 line) to 7.3 (LsA line). Based on the results, the pairs of lines LsA: P-33 and P-8: P-9 were found to be the most related; and the most genetically distant group was KhO-1 line, which originated as a cross between Khaki Campbell with Orpington duck.

Genetic diversity analysis of tropical and sub-tropical maize germplasm for Striga resistance and agronomic traits with SNP markers.

Striga hermonthica (Sh) and S. asiatica (Sa) are major parasitic weeds limiting cereal crop production and productivity in sub-Saharan Africa (SSA). Under severe infestation, Striga causes yield losses of up to 100%. Breeding for Striga-resistant maize varieties is the most effective and economical approach to controlling the parasite. Well-characterized and genetically differentiated maize germplasm is vital to developing inbred lines, hybrids, and synthetic varieties with Striga resistance and desirable product profiles. The objective of this study was to determine the genetic diversity of 130 tropical and sub-tropical maize inbred lines, hybrids, and open-pollinated varieties germplasm using phenotypic traits and single nucleotide polymorphism (SNP) markers to select Striga-resistant and complementary genotypes for breeding. The test genotypes were phenotyped with Sh and Sa infestations using a 13x10 alpha lattice design with two replications. Agro-morphological traits and Striga-resistance damage parameters were recorded under a controlled environment. Further, high-density Diversity Array Technology Sequencing-derived SNP markers were used to profile the test genotypes. Significant phenotypic differences (P<0.001) were detected among the assessed genotypes for the assessed traits. The SNP markers revealed mean gene diversity and polymorphic information content of 0.34 and 0.44, respectively, supporting the phenotypic variation of the test genotypes. Higher significant variation was recorded within populations (85%) than between populations using the analysis of molecular variance. The Structure analysis allocated the test genotypes into eight major clusters (K = 8) in concordance with the principal coordinate analysis (PCoA). The following genetically distant inbred lines were selected, displaying good agronomic performance and Sa and Sh resistance: CML540, TZISTR25, TZISTR1248, CLHP0303, TZISTR1174, TZSTRI113, TZDEEI50, TZSTRI115, CML539, TZISTR1015, CZL99017, CML451, CML566, CLHP0343 and CML440. Genetically diverse and complementary lines were selected among the tropical and sub-tropical maize populations that will facilitate the breeding of maize varieties with Striga resistance and market-preferred traits.

Genetic diversity among Ethiopian sweet sorghum [Sorghum bicolor (L.) Moench] accessions using simple sequence repeat markers

Sweet sorghum (Sorghum bicolor (L.) Moench) is the only grain and stalk crop that can be used for multipurpose. Despite its global significance and potential, it faced genetic erosion. These are due to low productivity and lower farmers' preferences, which is not considered one of the most important cereal crops in Ethiopia. To utilize and popularize these crops, understanding the genetic diversity and population structure is a pre-request. Therefore, this study was aimed to assess the genetic diversity and population structure of selected 82 Ethiopian sweet sorghum accessions using 10 simple sequence repeat (SSR) markers that represent seven geographic regions of Ethiopia. The study revealed a total of 116 alleles with a mean of 11.6 alleles per locus. All used microsatellite loci were highly polymorphic with polymorphic information content (PIC) ranging from 0.75 to 0.90 with an average of 0.82. They showed high gene diversity ranging from 0.59 to 0.81 with an overall mean of 0.70. There was a moderate genetic differentiation (FST = 0.21) showing the presence of high gene flow (Nm = 5.033) where 91 % of the total variation was accounted for within populations genetic variability. The clustering, principal coordinate analysis (PCoA) and population structure did not cluster the studied populations into a separate group according to their geographical origin. In conclusion, the highest intra-population diversity was observed among populations of North Wollo (He = 0.81) and South Wollo (He = 0.79), and hence these areas can be considered as hot spots for the identification of novel traits. Therefore, the present study has generated baseline information for breeders to improve Ethiopian sweet sorghum through breeding, management, and conservation of the available genetic resources.

Characterization of Lithuanian Tomato Varieties and Hybrids Using Phenotypic Traits and Molecular Markers.

The aim of this study was to evaluate phenotypic traits and genetic diversity of the 13 tomato (Solanum lycopersicum L.) varieties and 6 hybrids developed at the Institute of Horticulture Lithuanian Research Centre for Agriculture and Forestry (LRCAF IH). For the molecular characterisation, seven previously published microsatellite markers (SSR) were used. A24 and 26 alleles were detected in tomato varieties and hybrids, respectively. Based on the polymorphism information content (PIC) value, the most informative SSR primers for varieties were TMS52, TGS0007, LEMDDNa and Tom236-237, and the most informative SSR primers for hybrids were SSR248 and TMS52. In UPGMA cluster analysis, tomato varieties are grouped in some cases due to genetic relationships, as the same cluster cultivars 'Viltis' (the parent of cv. 'Laukiai') and 'Aušriai' (the progeny of cv. 'Jurgiai') are present. The grouping of all hybrids in the dendrogram is related to the parental forms, and it shows the usefulness of molecular markers for tomato breeding, as they can be used to trace the origin of hybrids and, eventually, varieties accurately. The knowledge about the genetic background of Lithuanian tomato cultivars will help plan targeted crosses in tomato breeding programs.

Application effectiveness of "Youxin-1" in genetic diversity and structure analysis of local chickens.

China's local chicken breeds are rich in resources, and have formed different germplasm characteristics in the process of long-term selection and evolution. Scientific assessment of population genetic diversity and identification of inter-breed genetic structure are of great value to the protection and innovative utilization of local chicken breed resource. In order to evaluate the application effectiveness of 23K SNP chip "Youxin-1" in the analysis of genetic diversity and genetic structure of local chickens, we used RADseq to identify genomic genetic variation of 21 local chicken breeds and developed 23K chip "Youxin-1". The genetic statistics of each variety were calculated based on two sets of SNP data, and correlation, fitting and phylogenetic analysis were carried out to evaluate the application effectiveness of the chip. The results showed that the observed heterozygosity (Ho), polymorphism information content (PIC), inbred coefficient (FROH) and genetic differentiation coefficient (Fst) calculated based on the two SNP data sets were basically consistent in the 21 local chicken breeds. The genetic diversity of Langya chicken (LA), Piao chicken (PJ) and Wenchang chicken (WC) was relatively rich. The genetic diversity of Bian chickens (BJ), Langshan chickens (LS), Gushi chickens (GS), Dongxiang blue-eggshell chickens (DX) and Beijing fatty chickens (BY) was relatively poor, and the correlation coefficients of Ho, PIC, FROH and average Fst in the two groups were 0.794, 0.901, 0.926 and 0.984, respectively, all reaching extremely significant levels (P<0.01) with a high degree of fit (P<0.001) and R2 were 0.644, 0.827, 0.916 and 0.927. For the two sets of SNP data, the evolutionary tree constructed by neighbor-joining (NJ) method and maximum likelihood (ML) method was reasonable, and the 21 local chicken breeds were generally divided into six categories, which was consistent with the formation history and geographical distribution of the varieties. The 23K chip also realized reasonable clustering of the five new varieties without individual deviation. There are some differences in the estimation of genetic statistics using SNP with different densities, and data standardization is needed. 23K chip has good efficacy in the analysis of genetic diversity and structure of local chickens.

Genetic structure and gene flow among populations of willow (Salix species)

The newly developed Salix hybrids were assessed for genetic diversity using ISSR (Inter Simple Sequence Repeats) molecular markers. The results revealed 88.08 polymorphism, 0.53 polymorphism information content, 4.70 effective multiplex ratio, 2.54 marker index, and 7.18 resolving power from the amplified primers. Clones of the Salix matsudana (MAT) population recorded a maximum mean number of effective alleles (1.42), Shannon information index (0.38), gene diversity (0.25), and percentage of polymorphic loci (82.24 %). The AMOVA (Analysis of molecular variance) results revealed a moderate genetic divergence with a genetic variation of 88 per cent within populations and 12 per cent among the populations. The highest value of total diversity (0.28) and gene diversity (0.24) was recorded between S. matsudana (MAT) and S. tetrasperma (TETRA) populations, while there was more gene flow between S. matsudana (MAT) and S. tetrasperma (TETRA) populations (5.86). The clustering pattern obtained through STRUCTURE software showed two main gene pools and a mixture of 6–7 gene pools to confirm the hybrids based on ISSR marker data. S. matsudana and S. tetrasperma clones showed the highest gene diversity due to their proximity from their original locations, resulting in the least amount of gene exchange among populations. Molecular characterization using ISSR markers was extremely useful for studying the genetic diversity among the willow hybrids and high genetic variability should be utilized for breeding purposes in the future.

Assessment of Genetic Diversity and Relatedness of Local Banana (Musa spp.) Cultivars in Malaysia Using Simple Sequence Repeat (SSR) Markers

Banana (Musa spp.) is an economically important crop widely consumed all over the world. Understanding the genetic diversity and relatedness between various banana cultivars is important to continuously improve its fruit characteristics, nutritional value, and disease resistance. This study aimed to develop a DNA fingerprinting panel using polymorphic simple sequence repeat (SSR) markers for the genetic characterisation of 11 banana cultivars in Malaysia. A total of 10 polymorphic SSR markers were developed into a multiplex PCR reaction and capillary electrophoresis to uniquely profile our collection of banana cultivars. The developed fingerprinting panel successfully amplified a total of 95 alleles, with 6 to 13 alleles per SSR marker. The average SSR marker polymorphic information content (PIC) value is 0.812, indicating the informativeness of the panel. Analysis of molecular variance (AMOVA) shows that 97% of the molecular variance from our banana collection is due to inter-variety genetic diversity, while the remaining 3% is due to intra-variety genetic diversity. A population structure analysis groups our collection of banana varieties according to the presence of at least one M. balbisiana (B) genome in their genetic makeup. The Cavendish variety, however, showed a distinct structure compared to the other cultivars. This SSR fingerprinting panel provides valuable insights into the genetic diversity and relatedness between banana cultivars in Malaysia. It has the potential to assist future banana breeding initiatives and serve as an effective quality control measure for verifying varieties in a tissue culture facility involved in banana planting materials production.

Exploring genetic diversity of yellow-berried night shade (Solanum virginianum L.) using genetic divergence and molecular markers

The rationale of this research was to explore the genetic divergence of 54 kantakari accessions (Solanum virginianum L. syn. S. surattense Burm. f.), to identify their significant traits, and unravel their genetic variations. Kantakari is a widely used medicinal plant in traditional medicine worldwide and is also known for its allopathic properties. The morphological descriptors and molecular markers (Random Amplified Polymorphic DNA) used to characterize these samples revealed significant within-accession heterogeneity, indicating the possibility of future selection. Twenty-three morphological and biochemical features were examined to assess taxonomic traits. Accessions were classified into six clusters based on Mahalanobis D2 statistics of 23 quantitative traits. Clusters V and VI had the largest intercluster distance (1183.81), whereas Cluster IV had the largest intracluster distance (D2 = 275.67) (Cluster V and VI). Random Amplified Polymorphic DNA marker amplification using 10 polymorphic primers revealed 79 alleles with an overall mean of 7.90 alleles per marker, with Polymorphism Information Content values varying from 0.11 to 0.37 (Mean = 0.30). Cluster assessment produced three distinct groups. In conclusion, the investigation underscores that substantial diversity was observed among the surveyed kantakari accessions. Using molecular markers in tandem with morphological characterization, presents a robust approach for elucidating the intricacies of species-specific genetic variation with greater accuracy and depth.

Development and validation of a 40 K liquid SNP array for the mud crab (Scylla paramamosain)

Genomic selection (GS) and genome-wide association studies (GWAS) have been widely implemented to accelerate the genetic improvement of important economic traits. Developing an efficient and reliable high-throughput genotyping tool is the premise and basis of implementing GS and GWAS on the mud crab (Scylla paramamosain). In this study, leveraging the whole-genome resequencing data of 146 mud crabs from the southeast coast of China, a total of 16,714,943 high-quality SNPs were discovered. Based on polymorphic information content and evenly distribution on 49 chromosomes, a total of 40,352 SNPs was selected to develop a 40 K liquid SNP array (named “Xiexin No. 1”) using the genotyping by target sequencing (GBTS) technology. The genotyping performance test showed that this SNP array had a high site polymorphism (over 92.70%) and individual calling rate (97.02%). Furthermore, the mean of SNP concordance, genotype concordance, non-reference sensitivity, and non-reference discrepancy between “Xiexin No. 1” SNP array and resequencing were identified to be 0.986, 0.954, 0.942, and 0.097, respectively. Using this SNP array data, the genomic heritabilities were evaluated as 0.887 ± 0.065, 0.643 ± 0.108, 0.599 ± 0.111, and 0.624 ± 0.111 for body weight (BW), carapace length (CL), carapace length (CW), and body height (BH) in a cultured population (233 crabs). Furthermore, five significant SNPs associated with growth traits were identified by GWAS. After annotation, one candidate gene (XP_027221997.1) associated with BW and one candidate gene (XP_027210446.1) associated with CW and BH were identified. Most importantly, the prediction accuracy of GBLUP for BW, BH, CL, and CW were 0.535 ± 0.064, 0.544 ± 0.101, 0.574 ± 0.087, and 0.585 ± 0.083, with the unbiasedness values of 0.988 ± 0.22, 1.015 ± 0.274, 1.011 ± 0.196 and 1.037 ± 0.235. In conclusion, the “Xiexin No. 1” SNP array provides an efficient and reliable platform for high-quality genotyping, which would greatly promote the genetic studies and thus accelerate the genetic improvement of mud crabs.

Development and validation of a novel forensic STR multiplex assay for blue (Anthropoides paradiseus), wattled (Bugeranus carunculatus), and grey-crowned crane (Balearica regulorum)

The blue crane (Anthropoides paradiseus), wattled crane (Bugeranus carunculatus), and grey-crowned crane (Balearica regulorum) are species of concern as their populations are declining and they face several threats including habitat loss, disturbance and illegal trade. In South Africa, these species are bred in captivity for trade purposes which is permitted and regulated globally under the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). Legal sustainable trade through captive breeding of endangered wildlife species such as cranes has been promoted to counteract the illegal trade of individuals from the wild. Captive breeding independent of wild populations may reduce the harvest pressures on wild bird populations which in turn benefit the recovery of exploited species. This approach is considered to be controversial by some individuals. Although captive breeding of endangered species, for both population sustainability and commercial purposes, is promoted to aid in conserving species, concerns have been raised with regards to breeding facilities being used for laundering of animals. To monitor the legal trade of cranes in South Africa a short tandem repeat (STR) assay following recommendations of the International Society for Forensic Genetics (ISFG) was developed and validated. An STR assay comprising of four multiplexes that include 16 STR markers and two gender determination markers was proven to be highly informative with average polymorphic information content (PIC) values of 0.806, 0.646 and 0.725 for A. paradiseus, B. regulorum and B. carunculatus respectively. In addition, the assay showed sufficient discriminatory power for parentage assignment of closely related individuals in all three species (A. paradiseus: PI = 1.7×10−24, PIsibs = 4.7×10−08, and B. carunculatus: PI = 1.4×10−19, PIsibs = 2.9×10−07 and B. regulorum: PI = 1.7×10−12, PIsibs = 5.0×10−05). Analysis of 251 samples suggested that the validated multiplex assay ensures reliability, reproducibility, and repeatability for applications in forensic case work where illegal trade of offspring is suspected through verifying parentage of captive birds in breeding facilities.

Preimplantation Genetic Testing of Spinocerebellar Ataxia Type 3/Machado-Joseph Disease-Robust Tools for Direct and Indirect Detection of the ATXN3 (CAG)n Repeat Expansion.

Spinocerebellar ataxia type 3/Machado-Joseph disease (SCA3/MJD) is a neurodegenerative disorder caused by the ATXN3 CAG repeat expansion. Preimplantation genetic testing for monogenic disorders (PGT-M) of SCA3/MJD should include reliable repeat expansion detection coupled with high-risk allele determination using informative linked markers. One couple underwent SCA3/MJD PGT-M combining ATXN3 (CAG)n triplet-primed PCR (TP-PCR) with customized linkage-based risk allele genotyping on whole-genome-amplified trophectoderm cells. Microsatellites closely linked to ATXN3 were identified and 16 markers were genotyped on 187 anonymous DNAs to verify their polymorphic information content. In the SCA3/MJD PGT-M case, the ATXN3 (CAG)n TP-PCR and linked marker analysis results concurred completely. Among the three unaffected embryos, a single embryo was transferred and successfully resulted in an unaffected live birth. A total of 139 microsatellites within 1 Mb upstream and downstream of the ATXN3 CAG repeat were identified and 8 polymorphic markers from each side were successfully co-amplified in a single-tube reaction. A PGT-M assay involving ATXN3 (CAG)n TP-PCR and linkage-based risk allele identification has been developed for SCA3/MJD. A hexadecaplex panel of highly polymorphic microsatellites tightly linked to ATXN3 has been developed for the rapid identification of informative markers in at-risk couples for use in the PGT-M of SCA3/MJD.

Cross transferability of finger millet SSR markers to little millet (Panicum sumatrense Roth. Ex Roem & Schult.)

Little millet is an important cereal known as a “nutra-grain' because of its numerous health benefits. Due to lack of genomic information, the present study analyzed the cross-transferability of finger millet SSR markers to little millet. SSR analysis using genomic DNA with 18 available markers in little millet revealed that 12 SSR markers had unique amplicons with the expected size, indicating 66.66 % cross-transferability. This indicates the conservation of the repetitive motifs AG, CTG, GTT, ACG, CGG, (GA)26, (TC)21, (CA)7N12 (GA)15, and (GA)7AA (GA)19 in both species. Genetic analysis with these transferable twelve SSR markers in 16 little millet genotypes revealed a total of 39 alleles with an average of 3.25 alleles per primer. The highest number of alleles (8) was found at GB-FM -53, while the lowest number of alleles (2) was found at GB-FM -67, GB-FM -87, GB-FM -98 and UGEP-101. Out of the total twelve amplified primers, four primers GB-FM -53, GB-FM -67, GB-FM -70 and UGEP-93 were found to be highly effective and best based on highest SSR primer index value, observed and effective number of alleles, Nei genetic diversity, Shannon information index and polymorphic information content. Finger millet SSR markers distinguished sixteen genotypes of little into two major clusters, where two genotypes, WV-151 and WV-152, were highly diverse. This study establishes the high cross-transferability of finger millet SSR markers to little millet facilitating genomic research and breeding efforts for genetically neglected little millet.

Development of SSR markers related to agarwood production and genetic diversity of Aquilaria sinensis (Lour.) Spreng wild populations

Aquilaria sinensis (Lour.) Spreng is an economically important tree that produces agarwood when subjected to mechanical wounding. However, the information regarding its heredity is limited. The breeding of A. sinensis has been hindered due to ambiguity in the sources of germplasm, genetic background, and varietal information. Simple sequence repeat (SSR) markers are ideal for studying genetic diversity and germplasm identification in plants. They offer the advantages of high polymorphism, good reproducibility, and co–dominance. Here, we mined SSR markers within agarwood–inducing genes and used them to explore the genetic diversity among A. sinensis natural germplasm. A total of 407 SSR loci were identified within 92 genes. We designed 96 primer pairs, among which 16 showed polymorphism and were subsequently used to analyze the genetic diversity and population structure of 179 A. sinensis individuals. A total of 107 alleles were identified, with an average of 7 alleles per locus, and their polymorphism information content ranged between 0.424 and 0.769, with an average of 0.569. The analysis of molecular variance revealed that genetic variation within the individuals accounted for 94 % of the total variation, inditing that the variation of A. sinensis is derived from individual variation. Furthermore, the structure analysis indicated that the natural populations of A. sinensis could be theoretically divided into 16 subgroups. The 16 polymorphic SSRs had strong cross–species transferability and distinguished individuals of A. agallochum (Lour.) Roxb. ex Finl. and A. malaccensis Lam. Taken together, these findings provide a useful resource for germplasm identification and molecular marker–assisted breeding of A. sinensis.

Genetic diversity and population structure of a modified three-way tomato hybrids for determining fruit size traits

The assessment of genetic diversity and genetic structure of crops has a vital impact on the plant breeding program, including the characterization, use and conservation of genetic material. The genetic diversity and genetic structure of a set of 94 F3 tomato hybrids were assessed with 25 polymorphic SNP markers of quantitative trait loci (QTLs) underlying fruit size in tomatoes using Sequenom Mass ARRAY system. A total of 50 alleles were amplified and the average polymorphic information content (PIC) was 0.2220. Nei's genetic distance ranged from 0 to 0.62. Therefore, single nucleotide sequence (SNP) markers detected a significantly high degree of polymorphism in tomato hybrids. Cluster analysis using the unweighted pair group method with arithmetic mean methods (UPMA) indicated that the tomato hybrids studied are grouped into four main groups, which is to some extent consistent with the size, shape and number of locules of the tomatoes studied. Analysis of population structure with SNP markers revealed three subpopulations. Association mapping using 25 SNP markers detected 9 markers with a significant association with mean fruit weight, fruit length, fruit diameter, number of locules, and fruit shape index. The nine markers detected in this study are recommended for the tomato fruit size improvement breeding program.

Genetic diversity analysis of Inner Mongolia cashmere goats (Erlangshan subtype) based on whole genome re-sequencing

BackgroundInner Mongolia cashmere goat (IMCG), renowned for its superior cashmere quality, is a Chinese indigenous goat breed that has been developed through natural and artificial selection over a long period. However, recently, the genetic resources of IMCGs have been significantly threatened by the introduction of cosmopolitan goat breeds and the absence of adequate breed protection systems.ResultsIn order to assess the conservation effectiveness of IMCGs and efficiently preserve and utilize the purebred germplasm resources, this study analyzed the genetic diversity, kinship, family structure, and inbreeding of IMCGs utilizing resequencing data from 225 randomly selected individuals analyzed using the Plink (v.1.90), GCTA (v.1.94.1), and R (v.4.2.1) software. A total of 12,700,178 high-quality SNPs were selected through quality control from 34,248,064 SNP sites obtained from 225 individuals. The average minor allele frequency (MAF), polymorphic information content (PIC), and Shannon information index (SHI) were 0.253, 0.284, and 0.530, respectively. The average observed heterozygosity (Ho) and the average expected heterozygosity (He) were 0.355 and 0.351, respectively. The analysis of the identity by state distance matrix and genomic relationship matrix has shown that most individuals’ genetic distance and genetic relationship are far away, and the inbreeding coefficient is low. The family structure analysis identified 10 families among the 23 rams. A total of 14,109 runs of homozygosity (ROH) were identified in the 225 individuals, with an average ROH length of 1014.547 kb. The average inbreeding coefficient, calculated from ROH, was 0.026 for the overall population and 0.027 specifically among the 23 rams, indicating a low level of inbreeding within the conserved population.ConclusionsThe IMCGs exhibited moderate polymorphism and a low level of kinship with inbreeding occurring among a limited number of individuals. Simultaneously, it is necessary to prevent the loss of bloodline to guarantee the perpetuation of the IMCGs’ germplasm resources.

Genetic diversity and population structure of Uganda cassava germplasm.

Cassava (Manihot esculenta Crantz) holds significant economic importance globally. Evaluating a diverse range of germplasm based on molecular characteristics not only enhances its preservation but also supports its utilization in breeding programs. In this study, we assessed genetic diversity and population structure among 155 cassava genotypes from Uganda using 5247 single nucleotide polymorphism (SNP) markers. Genotyping by sequencing (GBS) was employed for SNP discovery and to evaluate genetic diversity and population structure using the ADMIXTURE software. The cassava accessions comprised two populations: 49 accessions from Ugandan lines and 106 accessions resulting from crosses between South American and Ugandan lines. The average call rate of 96% was utilized to assess marker polymorphism. Polymorphic information content values of the markers ranged from 0.1 to 0.5 with an average of 0.4 which was moderately high. The principal component analysis (PCA) showed that the first two components captured ~ 24.2% of the genetic variation. The average genetic diversity was 0.3. The analysis of molecular variance (AMOVA) indicated that 66.02% and 33.98% of the total genetic variation occurred within accessions and between sub-populations, respectively. Five sub-populations were identified based on ADMIXTURE structure analysis (K = 5). Neighbor-joining tree and hierarchical clustering tree revealed the presence of three different groups which were primarily based on the source of the genotypes. The results suggested that there was considerable genetic variation among the cassava genotypes which is useful in cassava improvement and conservation efforts.

Emerging Cases of Cat-Transmitted Sporotrichosis Driven by Sporothrix brasiliensis in Northeast Brazil.

Cat-transmitted sporotrichosis is caused by the emerging fungal pathogen Sporothrix brasiliensis and constitutes a significant public health issue that affects people living in resource-poor urban centers in Brazil. The lack of knowledge about transmission dynamics makes it difficult to propose public health policies to contain the advance of sporotrichosis. We describe the recent emergence of 1,176 cases of sporotrichosis in cats (2016 to 2021) in the metropolitan region of Recife, Brazil, leading to significant zoonotic transmission and an overwhelming occurrence of S. brasiliensis as the etiological agent. Most cases were from cats in the cities of Olinda (408/1,176; 34.70%), Jaboatão dos Guararapes (332/1,176; 28.23%), and Recife (237/1,176; 20.15%). Molecular typing using amplified fragment length polymorphism (EcoRI-GA/MseI-AG) revealed low polymorphic information content (PIC = 0.2499) and heterozygosity (H = 0.2928), typical of an outbreak scenario. Dendrogram and multivariate cluster analysis revealed that isolates from Pernambuco are closely related to Rio de Janeiro isolates. We report a substantial occurrence of MAT1-2 idiomorphs in the metropolitan region of Recife (0:60 ratio; χ2 = 60.000, P < 0.0001). The limited population differentiation and genetic diversity of the isolates from Pernambuco suggest a recent introduction, possibly via a founder effect, from the parental population in Rio de Janeiro. Our findings emphasize the critical importance of molecular surveillance of S. brasiliensis for outbreak response. A comprehensive one-health strategy is mandatory to control the spread of cat-transmitted sporotrichosis driven by S. brasiliensis, encompassing sanitary barriers, quick diagnosis, and treatment.

Association study of allelic variation identified at yield contributing loci in rice (Oryza sativa L.)

The knowledge of functionally characterized genes and linked markers that govern grain yield and its related traits were used to unravel the markers/genes that associate with diversity of yield traits in a panel 30 novel rice genotypes comprising of indica, japonica, aromatic, landraces, interspecific crosses (O.glaberrima/O.sativa) etc. The ANOVA showed significant differences (P=&lt;0.001) for all traits among the genotypes. Molecular analysis was done by employing 37 gene-specific markers targeting 24 yield governing genes in rice. Two markers viz., RM223(YLD) on chromosome 8 and GW004(GW2, LOC_Os02g14720) on chromosome 2 were identified as polymorphic. Average PIC (polymorphic information content) value for these primers was 0.37, suggesting the availability of accountable variability at these loci. Cluster analysis grouped the genotypes into three clusters. Marker-trait-association analysis revealed significant association of the marker GW004 with panicle length, plant height and filled grains in rice. Pearson correlation study also supported the molecular associations through significant phenotypic associations for trait pairs plant height and filled grains, panicle length and plant height. The phenotypic variance explained (R2%) by the marker across panicle length, plant height and filled grains was ≥15%, suggesting major role of the locus/gene in controlling respective traits. Thus, GW004 marker could be employed in breeding programs for simultaneous selection of three traits panicle length, plant height and filled grains. From the current study it can be concluded that allelic variation studies using novel genotypes can result in the identification of suitable donors along with trait associated markers for rice yield improvement.