Amount Of Genetic Variation Research Articles

Screening Turkish maize landraces for kernel oil content and oil quality traits

AbstractIn this study, maize landraces, previously collected from different regions of Turkey through a national maize breeding project, were screened for kernel oil content and oil quality. After a seed reproduction in 2017, the screening trial was conducted in 2018, using an Augmented Experimental Design with 192 local maize populations along with seven check hybrids. Data were collected on oil, oleic acid, linoleic acid, monounsaturated (MUFA), polyunsaturated and saturated fatty acids, total carotenoid and total tocopherol contents. The results showed that there was a considerable amount of genetic variation among the Turkish maize landraces for almost all the traits investigated in this study. Some of the evaluated landraces are available that could be considered as high oil variety or special genotypes in terms of certain oil quality traits. Landraces had significantly higher values than checks for oil content, oleic acid, MUFA and tocopherol contents. Genetic analyses suggest that the kernel quality traits could be successfully manipulated using the investigated plant material. Heritability values were found high for all the traits of interest, except for saturated fatty acid and total carotenoid content. The promising landraces detected in this study could be exploited in future breeding programmes upon further evaluations at the population level.

Studies on genetic variability among yield attributing traits of fenugreek genotypes

The present study was conducted at Horticultural Complex, Vegetable Research Farm, Maharajpur, Department of Horticulture, College of Agriculture, Jabalpur (M.P.) during Rabi season 2016-17. The investigations revealed that the presence of considerable amount of genetic variability and mean values for all the characters have showed wide range of variability for all the morphological, phenological and qualitative traits studied. The values of phenotypic variance and phenotypic coefficient of variance were of higher magnitude than that of genotypic variance and genotypic coefficient of variance. The genotypic and phenotypic coefficient of variation was high for the characters seed yield per plant, number of pods per plant, number of branches at 90 DAS, test weight, number of leaves per plant at 30 DAS, number of branches at 60 DAS. High heritability was observed for number of leaves at 90 DAS, number of leaves at 30 DAS, number of pods per plant, shelling % and length of pods, plant height at 90 DAS, seed yield per plot and seed yield per hectare, number of branches per plant at 90 DAS, plant height at 60 DAS and plant height at 30 DAS. High estimates of GA as per cent of mean was recorded for seed yield per plant, number of pods per plant, test weight, number of leaves at 30 DAS, number of branches per plant at 90 DAS, number of leaves at 90 DAS, number of leaves at 60 DAS, and number of branches per plant at 60 DAS. High heritability coupled with high genetic advance was observed for traits like test weight, seed yield per plant, number of leaves at 30 DAS, number of pods per plant, number of leaves per plant at 30, 60, and 90 DAS.

Genetic diversity in threatened plant species Alnus nitida (Spach.) Endel

Alnus nitida (Spach) Endl. is an ethnobotanically important threatened plant species. The genetic diversity among the 50 different genotypes of Alnus nitida was carried out using sodium dodecyl sulfate poly acrylamide gel electrophoresis (SDS-PAGE) characterization. A considerable amount of genetic diversity (90%) was observed among the genotypes of A. nitida. The protein characterization was carried out on 12% gel electrophoresis. A total of 10 protein bands were detected in A. nitida genotypes. SDS-PAGE procedure is a useful method for the investigation of both genetic diversity and phylogenetic relationship. Especially, B-5 was monomorphic in A. nitida genotypes and was considered as species specific. All other bands/loci were polymorphic. These polymorphic bands displayed 12, 16, 72, 88, 2, 44, 84, 54 and 12 percent variation respectively. In the present examination, the high intra-specific diversity was observed representing SDS-PAGE is a powerful tool for determining the genetically diverse germplasms in A. nitida. The results obtained by this study could be helpful in the identification and selection of desired genotypes of Alnus nitida for conservation programmes in future. Today, there is still a need to assess genetic variation and protect genetic resources, especially of wild species for prospective benefits in plant conservation programmes.

Exploitation of heterosis for yield and yield related traits in okra (Abelmoschus esculentus (L.) Moench)

The present study was conducted in okra to estimate the magnitude of heterosis and to identify superior cross combinations for yield and its component traits. Thirty six F1s were developed by crossing 6 lines viz., Pusa Sawani (L1), Parbhani Kranti (L2), Arka Abhay (L3), Arka Anamika (L4), AE 65 (L5) and 14/11 (L6) and 6 testers viz., AE 64 (T1), AE 66 (T2), AE 17 (T3),14/4 (T4), 14/5 (T5) and 14/10 (T6) of okra in line x tester design during summer of 2018. All the 36 F1s along with their 12 parents (6 lines and 6 testers) and one standard check (Bhendi Hybrid CO 4) were evaluated in a randomized complete block design with two replications at Department of Vegetable Crops, Tamil Nadu Agricultural University, Coimbatore. Significance of mean squares due to treatments revealed the presence of considerable amount of genetic variability among the parents and cross combinations for all yield and yield attributing traits. The relative heterosis recorded the highest of 39.71 per cent in L3 x T2 (Arka Abhay x AE 66) in which twenty one cross combinations were positive and significant. Heterobeltiosis (dii) registered the highest of 28.65 per cent in Pusa Sawani x 14/4 (L1 x T4) in which eighteen cross combinations were significant and positive. The standard heterosis (diii) over check hybrid Bhendi Hybrid CO 4 recorded the highest of 37.12 per cent in Arka Anamika x 14/10 (L4 x T6) and twenty hybrids are positive and significant. Based on the results of the heterosis studies, it is clear that none of the 36 F1 hybrids of okra exhibited any consistency in terms of the direction and degree of heterosis over three bases viz., relative heterosis, heterobeltiosis and standard heterosis for all the characters studied. In the present study, the magnitude of standard heterosis was found to be highly variable in direction and magnitude for all the characters under study. Negative heterosis was desirable for the traits viz., days to first flowering, days to 50 per cent flowering, internodal length and per cent disease incidence in respect to yield while positive heterosis was considered to be desirable for the remaining traits viz., plant height, number of branches per plant, fruit length, fruit girth, fruit weight, number of fruits per plant and yield per plant. Arka Anamika x AE 17 (L4 x T3) expressed significant and positive standard heterosis over the standard parent Bhendi Hybrid CO 4 for eleven traits. The same cross combination Arka Anamika x AE 17 (L4 x T3) recorded significant and negative standard heterosis over the standard check for days to first flowering, days to 50 per cent flowering and per cent disease incidence. Similarly, the cross combination Arka Anamika x 14/10 (L4 x T6) recorded significant standard heterosis over the standard parent Bhendi Hybrid CO 4 for eleven characters. The cross combination of 14/11 x 14/4 (L6 x T4) also noted significant standard heterotic effect over the standard parent for ten traits. AE 65 x 14/4 (L5 x T4) is another best hybrid in terms of heterotic effect over the standard check in which it revealed significant values for nine traits. Considering the above facts, the above mentioned hybrids i.e., Arka Anamika x AE 17 (L4 x T3), Arka Anamika x 14/10 (L4 x T6), 14/11 x 14/4 (L6 x T4) and AE 65 x 14/4 (L5 x T4) could be selected for further improvement in yield and yield attributing components.

Temporal covariance structure of multi-spectral phenotypes and their predictive ability for end-of-season traits in maize

Key messageHeritable variation in phenotypes extracted from multi-spectral images (MSIs) and strong genetic correlations with end-of-season traits indicates the value of MSIs for crop improvement and modeling of plant growth curve.Vegetation indices (VIs) derived from multi-spectral imaging (MSI) platforms can be used to study properties of crop canopy, providing non-destructive phenotypes that could be used to better understand growth curves throughout the growing season. To investigate the amount of variation present in several VIs and their relationship with important end-of-season traits, genetic and residual (co)variances for VIs, grain yield and moisture were estimated using data collected from maize hybrid trials. The VIs considered were Normalized Difference Vegetation Index (NDVI), Green NDVI, Red Edge NDVI, Soil-Adjusted Vegetation Index, Enhanced Vegetation Index and simple Ratio of Near Infrared to Red (Red) reflectance. Genetic correlations of VIs with grain yield and moisture were used to fit multi-trait models for prediction of end-of-season traits and evaluated using within site/year cross-validation. To explore alternatives to fitting multiple phenotypes from MSI, random regression models with linear splines were fit using data collected in 2016 and 2017. Heritability estimates ranging from (0.10 to 0.82) were observed, indicating that there exists considerable amount of genetic variation in these VIs. Furthermore, strong genetic and residual correlations of the VIs, NDVI and NDRE, with grain yield and moisture were found. Considerable increases in prediction accuracy were observed from the multi-trait model when using NDVI and NDRE as a secondary trait. Finally, random regression with a linear spline function shows potential to be used as an alternative to mixed models to fit VIs from multiple time points.

Molecular Analysis For Salt Tolerance QTLs Emphasizing Saltol QTL in Some Egyptian and International Rice Genotypes (Oryza sativa L.)

Rice (Oryza sativa, L.) is one of the strategic crops in Egypt, and the improvement of its productivity is an essential requirement to ensure food security. Salinity is one of the major environmental stresses that limit the productivity of rice crop. 14 SSR markers linked to salinity were used to study the genetic diversity within salinity tolerance QTLs in 18 rice genotypes. All the utilized primers were polymorphic, the number of alleles ranged from 2 to 6 with an average of 3.42 per locus. The major frequency alleles ranged from 0.33 to 0.78 for RM562 and RM412, respectively.The PIC values varied from 0.79 to 0.37 with an average of 0.50. Seven SSR markers i.e. RM562, RM493, RM1287, RM223, RM242, RM10720, and RM5 were informative markers with PIC values more than 50%. Jaccard's similarity coefficients ranged from 0.07 to 0.93 with an average of 0.45.The studied genotypes were grouped into two major clusters at 0.18 similarity. The PCA analysis had the ability to classify the studied genotypes into clearly four separate clusters based on the origin and salinity tolerance.13 haplotypes other than the reference haplotype were identified. The number of genotypes per haplotype ranged from one to five. The current investigation highlighted the high amount of genetic diversity among the studied genotypes. Egyptian Yasmine, the fragrant genotype, was the most promising genotype where it has 50% of Pokkali alleles at Saltol QTL region and this makes it suitable to be used as salt tolerance donor for MAS in salinity tolerance molecular breeding program.

Assessment of Gene Flow to Wild Relatives and Nutritional Composition of Sugarcane in Brazil.

The commercial release of genetically modified organisms (GMO) requires a prior environmental and human/animal health risk assessment. In Brazil, the National Biotechnology Technical Commission (CTNBio) requires a survey of the area of natural occurrence of wild relatives of the GMO in the Brazilian ecosystems to evaluate the possibility of introgressive hybridization between sexually compatible species. Modern sugarcane cultivars, the focus of this study, derive from a series of hybridization and backcrossing events among Saccharum species. The so-called “Saccharum broad sense” group includes around 40 species from a few genera, including Erianthus, found in various tropical regions, particularly South-Eastern Asia. In Brazil, three native species, originally considered to belong to Erianthus, were reclassified as S. angustifolium (Nees) Trin., S. asperum (Nees) Steud., and S. villosum Steud., based on inflorescence morphology. Thus, we have investigated the potential occurrence of gene flow among the Brazilian Saccharum native species and commercial hybrids as a requisite for GMO commercial release. A comprehensive survey was carried out to map the occurrence of the three native Saccharum species in Brazil, concluding that they are sympatric with sugarcane cultivation only from around 14°S southwards, which precludes most Northeastern sugarcane-producing states from undergoing introgression. Based on phenology, we concluded that the Brazilian Saccharum species are unable to outcross naturally with commercial sugarcane since the overlap between the flowering periods of sugarcane and the native species is limited. A phylogenomic reconstruction based on the full plastid genome sequence showed that the three native Saccharum species are the taxa closest to sugarcane in Brazil, being closer than introduced Erianthus or Miscanthus. A 2-year study on eight nutritional composition traits of the 20 main sugarcane cultivars cultivated in Brazil was carried out in six environments. The minimum and maximum values obtained were, in percent: moisture (62.6–82.5); sucrose (9.65–21.76); crude fiber (8.06–21.03); FDN (7.20–20.68); FDA (4.55–16.90); lipids (0.06–1.59); ash (0.08–2.67); and crude protein (0.18–1.18). Besides a considerable amount of genetic variation and plastic responses, many instances of genotype-by-environment interaction were detected.

Genetic variability and character association studies in French bean (Phaseolus vulgaris) in Nilgiri hills of Tamil Nadu

In the present investigation, the genotypic and phenotypic coefficients of variation, heritability, correlation and path coefficient analysis were worked out for yield and its contributing characters of 77 French bean (Phaseolus vulgaris L) genotypes at Horticultural Research Station, TNAU, Udhagamandalam, Nilgiris,Tamil Nadu, India in 2018 with the objective of identifying desirable traits contributing to higher yield in French bean. Phenotypic coefficient of variation was slightly higher than genotypic coefficient of variation for all the characters suggesting the presence of environmental influence to some extent in the expression of these characters. High heritability along with high genetic advance as per cent of mean was observed for plant height, pods per plant and seed yield per plant indicating that these characters would be amenable for phenotypic selection. A considerable amount of genetic variability was observed among all the genotypes for all the characters under study. Genotypic coefficients variance and Phenotypic coefficients variance were highest for seed yield per plant followed by biological yield and number of pods per plant. High genetic advance coupled with high heritability were observed for plant height, days to 50% flowering, number of primary branches per plant, pod length, pod girth, seeds per pod, number of pods per plant, biological yield and seed yield per plant. Combined results of correlation coefficient and path analysis revealed that pods per plant, pod length, pod girth, biological yield and seed yield are major component traits for improvement of grain yield. The present findings could be useful in selecting superior genotypes in French bean breeding programmes.

Genetic Variability, Correlation and Path Analysis Study on Snap Melon (Cucumis melo L. var. momordica) Farmer’s Varieties

The present investigation was carried out to assess the genetic variability, correlation and path analysis for yield and its component traits in 15 Snap melon farmer's varieties of Eastern Uttar Pradesh for 17 quantitative characters during Kharif- 2018. Analysis of variance showed significance differences for all the quantitative traits at 1% and 5% level of significance. Indicating considerable amount of genetic variation in different farmer's varieties of Eastern Uttar Pradesh. The low difference between GCV and PCV depicted that a little or no influence of environment on the expression of the various quantitative traits. High heritability coupled with high genetic advance was depicted by for fruit weight at average followed by number of seeds fruit−1 and 100 seed weight, indicating a predominance of additive gene effects and the possibilities of effective selection based on these traits for snap melon improvement. Therefore, these traits may be used as selection indices for genetic improvement of Snap melon farmer's varieties. Node at first female flower appearance followed by number of fruits plant−1, fruit length, fruit diameter, fruit flesh thickness and fruit weigh at average show positive significant correlation and direct effect on yield plant−1 further proves their genetic worth for selection breeding through pure line/pedigree method.

Hybridity testing and heterosis in relation to genetic divergence in chickpea (Cicer arietinum L.) under rice based cropping system

The present investigation was carried out to determine the genetic purity of the crosses in chickpea using SSR markers. The application of molecular markers SSR21 and SSR22 in F1 hybrids and their parental lines produced two bands indicating similarity among the hybrids and parental lines. The mixtures and off-types did not show similar banding pattern as compared to hybrids. The D2 analysis showed high amount of genetic diversity among parents and parental lines. The value of heterosis in a cross, JG 315 x ICCV 96029 was positive significantly higher for days to 50 % flowering, days to maturity, secondary branches plant-1, pods plant, biological yield and seed yield plant-1, however, it was significantly negative only for 100 seed weight.

Genetic status of the endangered plant species Gladiolus palustris in the western part of its distribution area

Many endangered plant species suffer from the effects of ongoing fragmentation of their populations leading to a loss of genetic diversity through genetic drift. In addition, populations of rare plants may also be affected by hybridization with other plant species. We studied the genetic population structure of populations of the endangered Gladiolus palustris in the western limit of its distribution area using AFLP markers. In addition, we clarified the taxonomic status of populations where hybridization with the closely related G. imbricatus was suspected based on morphology by sequencing the ITS region of the nuclear ribosomal DNA as well as two regions of the chloroplast DNA. Our analysis of the genetic population structure of G. palustris revealed a strong differentiation among geographical regions, which was much higher than the differentiation among populations within regions. Most populations retained a considerable amount of genetic variation. To counteract the future loss of genetic diversity through drift, we recommend using the largest populations per region as seed source to increase genetic diversity in genetic depauperate populations of the same region. Our genetic analyses indicated that some French populations of G. palustris are of hybrid origin. These hybridization events are likely to be ancient as these populations are very isolated and some parent taxa went regionally extinct. As these hybrid populations may elucidate post-glacial distribution patterns of related Gladiolus taxa, we advocate that they deserve the same conservation efforts as purebred ones.

Molecular genetic diversity and relationship of indigenous sheep breeds of Pakistan based on nuclear microsatellite loci

<p>En Pakistán los recursos genéticos ovinos son abundantes, disponiéndose de varias diferentes castas extendidas en todo el país. No obstante, la diversidad molecular de las razas de ovejas es poco conocida en la región. Por ello, en el presente estudio se investigaron 16 marcadores microsatelitales de las razas indígenas Buchi y Hashtnagri, en las provincias de Pendjab y Balochistan respectivamente. Para indagar la diversidad genética se obtuvieron muestras de sangre de 25 animales de cada raza. El promedio del número de alelos en Buchi y Hashtnagri fue de 3,375±1,455 y 3,50±1,591 respectivamente. Los promedios de heterocigosis registradas fueron de 0,878±0,204 para la raza Buchi y 0,885±0,218 para Hashtnagri. Los índices de Shannon fueron 1,032±0,371 para Buchi y 1,070±0,412 para Hashtnagri, respectivamente. La estimación de los coeficientes de endogamia (FIS y FIT) mostró valores negativos, en tanto que el flujo genético (migración) fue de 10,09 y el promedio de la diferencia poblacional (FST) resultó de 2,4%. En ambas razas, el índice de información polimórfica fue 0,56, indicando el valor del marcador del tablero. Entre las ovejas Buchi y Hashtnagri, la distancia genética estándar de Nei (Ds) fue 0,0218. Según estos resultados, ambas razas mostraron considerable diversidad genética. Los datos obtenidos permiten vislumbrar una promisoria mejoría en el área de la conservación y en el diseño de las estrategias para la cría de ovejas en el futuro cercano.</p>

Latitudinal divergence in a widespread amphibian: Contrasting patterns of neutral and adaptive genomic variation.

Stochastic effects from demographic processes and selection are expected to shape the distribution of genetic variation in spatially heterogeneous environments. As the amount of genetic variation is central for long-term persistence of populations, understanding how these processes affect variation over large-scale geographical gradients is pivotal. We investigated the distribution of neutral and putatively adaptive genetic variation, and reconstructed demographic history in the moor frog (Rana arvalis) using 136 individuals from 15 populations along a 1,700-km latitudinal gradient from northern Germany to northern Sweden. Using double digest restriction-site associated DNA sequencing we obtained 27,590 single nucleotide polymorphisms (SNPs), and identified differentiation outliers and SNPs associated with growing season length. The populations grouped into a southern and a northern cluster, representing two phylogeographical lineages from different post-glacial colonization routes. Hybrid index estimation and demographic model selection showed strong support for a southern and northern lineage and evidence of gene flow between regions located on each side of a contact zone. However, patterns of past gene flow over the contact zone differed between neutral and putatively adaptive SNPs. While neutral nucleotide diversity was higher along the southern than the northern part of the gradient, nucleotide diversity in differentiation outliers showed the opposite pattern, suggesting differences in the relative strength of selection and drift along the gradient. Variation associated with growing season length decreased with latitude along the southern part of the gradient, but not along the northern part where variation was lower, suggesting stronger climate-mediated selection in the north. Outlier SNPs included loci involved in immunity and developmental processes.

Genetic analysis of reproductive performance in sows during porcine reproductive and respiratory syndrome (PRRS) and porcine epidemic diarrhea (PED) outbreaks

BackgroundPorcine reproductive and respiratory syndrome (PRRS) is one of the most infectious swine diseases in the world, resulting in over 600 million dollars of economic loss in the USA alone. More recently, the USA swine industry has been having additional major economic losses due to the spread of porcine epidemic diarrhea (PED). However, information regarding the amount of genetic variation for response to diseases in reproductive sows is still very limited. The objectives of this study were to identify periods of infection with of PRRS virus (PRRSV) and/or PED virus (PEDV), and to estimate the impact their impact on the phenotypic and genetic reproductive performance of commercial sows.ResultsDisease (PRRS or PED) was significant (P < 0.05) for all traits analyzed except for total piglets born. Heritability estimates for traits during Clean (without any disease), PRRS, and PED ranged from 0.01 (number of mummies; Clean and PED) to 0.41 (abortion; PED). Genetic correlations between traits within disease statuses ranged from −0.99 (proportion born dead with number weaned; PRRS) to 0.99 (number born dead with born alive; Clean). Within trait, between disease statuses, estimates ranged from − 0.17 (number weaned between PRRS and PED) to 0.99 (abortion between Clean and PRRS).ConclusionResults indicate that selection for improved performance during PRRS and PED in commercial sows is possible and would not negatively impact performance in Clean environments.

Investigation of the genetic structure of Kabyle and Chaouia Algerian populations through the polymorphism of Alu insertion markers

Background: In Algeria, as in all North Africa, Berbers constitute the old background of the population. Today, Berber speakers account for only ∼ 25% of Algerians. This decline is the product of a complex human settlement from pre-history to recent invaders.Aim: This study aims to determine the genetic diversity level within a sample of five Algerian Berber speaking populations in order to contribute to resolving issues about the North African population settlement.Subjects and methods: Two Algerian Berber groups (Kabyle and Chaouia), originated from five administrative regions from Algeria, were typed for 11 Alu Insertions. Analysis has been based on Fst genetic distance, AMOVA, NMDS and distance to the centroid model.Results: No genetic differentiation has been observed between all Algerian Berbers discarding any geographical or ethnic effect. Comparative analyses based on Fst genetic distance did not show significant affinities between North Africans and either South Europeans or Middle Easterners, except genetic proximity between Algerians and Iberians. The amount of genetic diversity among Algerians and North African populations detected by the distance to the centroid model was significant compared with other North Mediterranean populations.Conclusion: A strong genetic homogeneity has been found between Algerian Berbers. Global genetic diversity based on Alu markers is following the isolation by distance model, except for some European populations.

Conservation Hedges:

In May 2014, the first planting of the Royal Botanic Garden Edinburgh (RBGE) conservation hedge took place, when the Reverend Anne Brennan planted a tree which had originated as a cutting from the ancient and historic European yew, Taxus baccata, in the churchyard of her church at Fortingall, Perthshire. This is one of almost 2,000 plants that will eventually form a conservation hedge of significant scientific and conservation value. The International Conifer Conservation Programme (ICCP), based at RBGE, has actively sought other opportunities to establish conservation hedges via its network of ‘safe sites’, using a range of different conifer species. This initiative is being driven by the potential for relatively large numbers of genotypes from a single threatened species to be stored in a linear space. It is well established that seed banks have a great capacity to store large amounts of genetic diversity, so we should simply consider conservation hedges in a similar manner. These super-hedges cram relatively large amounts of genetic material into a small space, capturing a great range of wild traits and potentially contributing to the restoration of wild populations. To date, conservation hedges have been planted at five separate locations at RBGE’s Edinburgh Garden as well as at four ICCP external ‘safe sites’. Although this article focuses on the establishment of conservation hedges using conifers, we have also highlighted some conservation hedges that comprise non-coniferous species.

Accuracy of genomic evaluation with weighted single-step genomic best linear unbiased prediction for milk production traits, udder type traits, and somatic cell scores in French dairy goats

Genomic evaluation of French dairy goats is routinely conducted using the single-step genomic BLUP (ssGBLUP) method. This method has the advantage of simultaneously using all phenotypes, pedigrees, and genotypes. However, ssGBLUP assumes that all SNP explain the same amount of genetic variance, which is unlikely in the case of traits whose major genes or QTL are segregating. In this study, we investigated the effect of weighted ssGBLUP and its alternatives, which give more weight to SNP associated with the trait, on the accuracy of genomic evaluation of milk production, udder type traits, and somatic cell scores. The data set included 2,955 genotyped animals and 2,543,680 pedigree animals. The number of phenotypes varied with the trait. The accuracy of genomic evaluation was assessed on 205 genotyped Alpine and 146 genotyped Saanen goats born between 2009 and 2012. For traits with unknown QTL, weighted ssGBLUP was less accurate than, or as accurate as, ssGBLUP. For traits with identified QTL (i.e., QTL only present in the Saanen breed), weighted ssGBLUP outperformed ssGBLUP by between 2 and 14%.

The pathogenesis of genetically diverse strains of Crimean-Congo hemorrhagic fever virus in the cynomolgus macaque model

Purpose: Crimean-Congo hemorrhagic fever virus (CCHFV) is a tick-borne virus with a wide geographical distribution, which includes Africa, the Balkans, the Middle East, Russia and western Asia. As a result of its wide dissemination, there is a considerable amount of genetic diversity amongst different CCHFV strains. Infection with CCHFV can cause a severe, often fatal, human disease characterized by fever and hemorrhage. No licensed vaccines or therapeutics currently exist to treat infection with CCHFV. The development of a non-human primate (NHP) model that recapitulates human disease would significantly benefit development efforts for medical countermeasures to CCHFV. In a recent study by another group, cynomolgus macaques were infected intravenously with a European isolate of CCHFV and the animals experienced a severe, sometimes lethal, disease state. We expanded upon this initial study using the same intravenous NHP model to compare disease progression with the previous European isolate versus another contemporary isolate of central Asian origin. Methods & Materials: Two groups of cynomolgus macaques were infected intravenously with either the European isolate (Kosova Hoti) or the Asian isolate (Afg09-2990). Animals were then monitored with real-time temperature telemetry and regularly assessed across a range of clincial criteria. Serological collection was performed on a daily basis during acute phase, and a range of viremic, hematological, blood chemistry, and immunological assays were performed. Results: While we achieved a robust disease state for both challenge groups, our CCHFV disease model was not as severe as the initial study reported by Haddock, et al. Interestingly, despite its higher initial viremic load, Afg09-2990 appeared to resolve more quickly than Kosova Hoti with regard to both fever and clinical score criteria. Aside from this, both virus strains caused largely analogous disease states, which reflected many symptoms seen in human disease. Conclusion: In this comparative study, we found that European and Asian CCHFV strains caused very similar disease profiles in cynomolgus macaques. This strongly suggests that future medical countermeasures can be tested in this NHP model for multiple CCHFV strains. In addition, the differences we observed in the severity of our disease model relative to that previously reported suggests that further model optimization may be desirable.

Genome-wide association study for response to vaccination in Angus calves1

BackgroundBovine respiratory disease complex (BRDC) is one of the most important sources of loss within the beef cattle industry in the USA. Steps have been taken to reduce the incidence of BRDC through vaccination. Despite the effectiveness of vaccines, large proportions of cattle still experience morbidity and mortality. Identification of genomic regions that are associated with variation in response to vaccination would allow for the selection of individuals genetically predisposed to respond to vaccination based on specific markers, while heritability and accuracy estimates would help facilitate genomic selection. This in turn may lead to selection for beef cattle herds that may have lower incidence rate of BRDC after vaccination. This study utilizes an Angus herd of more than 2000 head of cattle to identify these regions of association.ResultsGenome wide association studies were performed for viral neutralization antibody level and response to vaccination traits against four different viruses associated with BRDC: bovine viral diarrhea virus 1 and 2 (BVDV1 and BVDV2), bovine respiratory syncytial virus (BRSV), and bovine herpesvirus (BHV1). A total of six 1-Mb windows were associated with greater than 1% of the genetic variance for the analyzed vaccination response traits. Heritabilities ranged from 0.08 to 0.21 and prediction accuracy ranged from 0.01 to 0.33 across 7 different vaccination traits.ConclusionsAlthough six 1-Mb windows were identified as associated with 1% or greater genetic variance for viral neutralization antibody level and response to vaccination traits, few genes around these windows could readily be considered candidates. This indicates the need for further functional genomic annotation, as these regions appear to be gene deserts. Traits ranged from lowly to moderately heritable, which indicated the potential for selection of individuals that are genetically pre-disposed to respond to vaccination. The relatively low amount of genetic variance accounted for by any 1-Mb window indicated that viral neutralization antibody level and response to vaccination traits are polygenic in nature. Selection for these traits is possible, but likely to be slow due to the low heritabilities and absence of markers with high genetic variation associated with them.

Genetic diversity in mango cultivars revealed by SSR markers

The existing genetic diversity is the main source of variability in any fruit crop improvement program which serves as a gene pool for identifying superior alleles governing key horticultural traits through allele mining/association mapping. Therefore the first attempt was made to determine the genetic diversity in 60 mango cultivars using 100 leaf transcriptome sequence derived novel genic SSR markers. A total of 263 alleles were amplified with mean of 3.0 alleles per SSR locus. Size of the amplified alleles ranged from 130 to 300 bp. Mean polymorphic information content (PIC) was 0.45, which demonstrated the presence of moderately high amount of genetic variation between the selected mango cultivars. Neighbour Joining (NJ) tree analysis detected two major groups belongs to North-West and South-East India, Florida, USA and Brazil. The comprehensive molecular characterization of the present set of mango cultivars contributes to the knowledge about the levels and distribution of genetic diversity within these geographically diverse mango cultivars. In addition to that the information generated in this study could be utilized in association mapping and marker assisted selection in mango improvement programme.