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Tetraploid wheat species from Ethiopia hold ample genetic variation, which could provide a source for improvement of wheat. A total of 196 Ethiopian tetraploid wheat (Triticum turgidum spp.) accessions, including 174 landraces and 22 improved cultivars, were evaluated at Sinana and Debrezeit to assess morphological variation, genetic advance, heritability and correlation based on 11 phenotypic traits. Except for spike length, highly significant variation (P < 0.001) among genotypes for all traits was observed. The observed mean and range values of the phenotypic traits revealed high variability in the accessions. Phenotypic coefficient of variation (PCV) and genotypic coefficient of variation (GCV) values were high for grain yield, biomass yield and harvest index. Seed yield showed highly significant (P < 0.001) negative correlation with days to booting and days to maturity and positive correlation with all traits. The estimates of heritability (H2) for grain yield and the number of spikelets per spike respectively ranged from 41.78 to 84.62%. The genetic advance as a percentage of mean was low for the number of seeds per spikelet, days to booting and days to maturity; intermediate for plant height, thousand kernel weight and spike length and high for the number of spikelets per spike, the number of effective tillers per plant, grain yield, biomass yield and harvest index, respectively. The number of spikelets per spike gave a high value of genetic advance and heritability implying high genetic gain from its selection.
Gerbera is an important commercial flower crop in the world. Augmenting the genetic diversity is desirable for further improvement in Gerbera breeding programme. Thirty-seven (37) Gerbera accessions were evaluated and analysed for genetic variability, heritability, correlation and path coefficient analysis using yield and quality traits. Results showed that phenotypic coefficients were higher than genotypic coefficients of variation for all the characters. All the traits, except stalk and flower diameter, had high heritability (>60%) and genetic advance (>20%). Based on cluster analysis, the 37 accessions were grouped into seven clusters. Cluster I consists of the maximum number of genotypes (22), while clusters IV–VII are monogenotypic with unique traits. Cluster analysis (D2) showed wider genetic diversity within and between the clusters. The first four principal components (Eigenvalue >1) contributed 72.3% of the total variation. The number of leaves, number of flowers and flower stalk length contributed the most to genetic divergence. Flower yield showed a significant positive genotypic correlation with the number of leaves and suckers. The path analysis (genotypic) revealed that number of suckers, flower stalk diameter and flower stalk length contribute major positive direct effects on number of flowers. Therefore, the wide genetic variability existing in the germplasm may facilitate improvement in gerbera crops. Superior lines (RCGH-12, -22, -114, -117) with higher yield (>23 flowers/plant) and vase life (>5 days) could be promoted for commercial production under open field conditions. While RCGH 28 has a dwarf flower stalk that can be promoted for pots and decoration purposes.
The study of polymorphism of glutenin makes it possible to identify and isolate desirable genotypes with higher grain quality. In the last few years, only a part of the genetic diversity among the modern and popular wheat germplasm and varieties based on the polymorphism of glutenin subunits are captured. To address this 107 wheat varieties released across different agricultural zones in India, were used to investigate HMW-GS and LMW-GS allele polymorphism, gene diversity and genetic variation in the Glu-1 and Glu-3 loci. Among the different HMW-GS, the highest genetic variation was observed at the Glu-D1 locus with both Glu-D1a and Glu-D1d possessing genetic variation of 0.490, 0.484 respectively. The highest genetic variation at the Glu-A3 locus was observed at the Glu-A3c and GluA3b possessing a genetic variation of 0.463, 0.411 respectively. This was followed by the Glu-B3j having a genetic variation of 0.386 at the Glu-B3 locus. Over 20 years a remarkable increase in the Glu-D1d allele is observed in the newly released varieties in India. Among all the zones, Glu-A1-null is the least frequent allele at the Glu-1 locus, however, it is present as the predominant allele in the NHZ of India. This study elucidates the relationships of these HMW and LMW allelic frequencies and genetic variation with their geographical distribution over the two different periods. This study provides reference data that can be used to assist the breeding, quality evaluation and development of good-quality wheat varieties.
Maize is among major field crops which provides food, fodder and various byproducts to the industry. Development of better performing varieties is very important to enhance and strengthen the maize production system. In this study ethyl methanesulfonate (EMS) is used to induce genetic variation in maize. Mutant population was derived from two genotypes 100,003 and 100,004. EMS was applied under three different concentrations of 25, 50 and 75 mM. 25 mM was found as an ideal concentration resulting in maximum survival rate. Total 10 SSRs were used in this study, which amplified 28 alleles with average of 2.7 alleles. Analysis of molecular variance showed significant differences present among individuals. Average heterozygosity for mutants derived from 100,003 and 100,004 was 0.58 and 0.53, respectively. UPGMA analysis characterized the mutants into two main and many sub clusters. According to the principal component analysis, PC 1 and 2 contributed to 64.2% variability with eigenvalue greater than 1. Statistics showed maximum coefficients of variance in traits of leaf area, cobb height and plant height. Promising mutants were also identified and recommended for future breeding programme. In conclusion, EMS mutagenesis is an effective technique to develop novel mutants that can be exploited in future breeding programmes.
Genetic gains (ΔG) are determined by the breeders' equation ΔG = [(ck σ2G)/(y σP)], where c, k and y are the parental control, a function of the selection intensity and number of years to complete one selection cycle, respectively, while σ2G and are σP the genetic variance and the square root of the phenotypic variance. Plant breeding programs should deliver above 1% of annual genetic gains after testing and selection. The aim of this research was to estimate genetic gains in potato breeding after testing of cultivars released in western Europe in the last 200 years under high yield potential, and stress-prone environments affected by a pest (late blight) or daylength. The annual genetic gains for tuber yield and flesh's starch content for potato breeding in Europe were about 0.3 and −0.1%, respectively, thus telling that the realized genetic gains of foreign cultivars for both traits are small or negative, respectively, in the Nordic testing sites. The national annual productivity gains in potato grown in Sweden were on average 0.7% in the last 60 years while the genetic gains for tuber yield considering only the table cultivars released after the 2nd World War were about 0.36%, thus showing that breeding contributed just above ½ of it. Furthermore, genetic gains for breeding low reducing sugars in the tuber flesh, and high host plant resistance to late blight were small (<0.2% per year). These results highlight that genetic gains are small when testing bred germplasm outside their target population of environments.
The study determined the prevalence and genetic population structure relationships of Cysticercus tenuicollis (Taenia hydatigena metacestode) retrieved from the goats slaughtered in north India. An overall prevalence of 9.62% (59/613) was recorded. Genetic population structure relationships were assessed by targeting partial cytochrome c oxidase subunit 1 mitochondrial gene sequence. Phylogenetic tree analysis revealed that all the present study representative isolates (n = 7) formed a major clade and grouped with T. hydatigena isolates retrieved from sheep, goats, pigs and dogs, originating from China, Iran, Nigeria, Ghana and Poland. However, a single isolate from Himachal Pradesh (isolate 3) formed a subgroup within the clade. The neutrality and diversity indices revealed high values of haplotype diversity [Hd = 0.99695 (0.95238–1.0000)] and low nucleotide diversity (π = 0.49276), which was indicative of demographic expansion and low gene flow, suggesting that Indian T. hydatigena isolates were not genetically differentiated. Tajima's D (−1.26988) and Fu and Li's D statistics values (−0.74556) were negative, demonstrating deviations from neutrality and both propounded recent population expansion or purifying selection. Results highlighted a low genetic diversity of T. hydatigena metacestodes across the geographical range of north India.
Hybridization can play an important role in the evolution of invasiveness. Eurasian watermilfoil (Myriophyllum spicatum L.) is a widespread aquatic invasive plant species that hybridizes with native northern watermilfoil (Myriophyllum sibiricum Kom.). Previous studies have found mixed evidence for whether hybrid watermilfoil (Myriophyllum spicatum × sibiricum) and pure M. spicatum differ in vegetative growth rate and herbicide response. While several studies have emphasized variation in these traits among M. spicatum × sibiricum genotypes, variation within M. spicatum has not been considered. Therefore, it is unclear how much genetic variation influences invasive traits and management outcomes within M. spicatum versus between M. spicatum and M. spicatum × sibiricum. If M. spicatum × sibiricum genotypes are always more invasive than M. spicatum genotypes, simply distinguishing taxa may be sufficient for identifying lake management priorities; however, if significant phenotypic overlap is observed between taxa, distinguishing individual genotypes may be important for tailoring management strategies. We performed replicated trials of a vegetative growth and 2,4-D assay to measure clonal variation in growth rate and herbicide response of M. spicatum and M. spicatum × sibiricum. Our results indicate that M. spicatum × sibiricum exhibits higher average vegetative growth than M. spicatum, regardless of whether it was treated with subsurface applications of 2,4-D. We did not observe interactions between taxon and treatment or between genotype and treatment. Despite differences between M. spicatum and M. spicatum × sibiricum in average vegetative growth, there was substantial overlap between taxa. For example, we found that the fastest-growing genotype of pure M. spicatum did not differ significantly in average growth from the fastest-growing M. spicatum × sibiricum genotype. The potential for overlap between these invasive Myriophyllum taxa suggests that distinguishing and characterizing genotypes may be more informative for management than simply distinguishing between M. spicatum and M. spicatum × sibiricum.
The neuropeptide oxytocin (OXT) has been linked to interpersonal trust. While initial behavioral studies demonstrated a facilitating effect of OXT on trusting behavior, more recently these findings have been challenged. In this chapter we review the literature reporting two approaches that are used to evaluate OXT’s effects: exogenous OXT administration and the investigation of the endogenous OXT system. With respect to trust, we report results from studies investigating trusting behavior, mostly using economic games, and studies looking on the intention to trust other individuals. Overall, clear evidence for a direct trust-promoting effect of OXT as proposed by early studies cannot be found. Instead, there is evidence that the relationship between OXT and trust is modulated by manifold contextual factors that are closely interrelated, e.g., social affiliation, personality traits, gender, mental disorders, and genetic disposition. Furthermore, it could be argued that the effect of OXT on trust is not a specific one but only a subphenomenon of the more general prosocial effect of the neuropeptide.
Future research should aim to conceive models of the OXT–trust connection considering the interactions between genes, brain functioning, and the environment, advancing the knowledge of understanding interpersonal trust.
The elephant seal nomenclature is arbitrary, based on fallacies, and is impractical. Elephant seals are true seals that originated in the North Atlantic 15 to 20 million years ago. Today, the northern species is found along the west coast of North America and the southern species inhabits sites around the Antarctic continent. The two species have been separated for a minimum of 5,000 years but the exact duration is unclear. The northern elephant seal population was abundant before the seals were hunted for their blubber oil in the first half of the nineteenth century. The slaughter was so extensive and relentless that by the late-nineteenth century, the species was considered extinct. Approximately 20 individuals survived, however, on a volcanic island in Mexico. The population experienced a severe population bottleneck and lost genetic diversity. The southern species was also hunted by sealers, but its population was not reduced as drastically.
Melon (Cucumis melo L.) is an economically important vegetable crop worldwide. Karnataka state of southern India is rich in melon landraces and wild relatives, which are potential sources of genetic diversity for crop improvement. Here we report on the collection, characterization and documentation of previously unexplored landrace and wild material to broaden the availability of this genetic diversity for use in melon improvement. Accessions of botanical groups, momordica, kachri, chandalak, reticulatus, acidulus and indicus, intermediate forms of acidulus and momordica, and three melons of an unknown group were sourced directly from farmers of eight agro-ecological regions. Twenty-three representative melon landraces and wild relatives, along with four reference varieties of different botanical groups, were evaluated for agronomic traits during the year 2016. Very wide and distinctive genetic variations were observed among the melon accessions for ovary characters, sex expression, days taken to first fruit maturity, external and internal fruit traits, and fruit cracking (splitting). The remarkable variability displayed among the melon accessions as observed from the study demonstrates the importance of them as a valuable genetic reservoir for melon improvement.
Essential tremor (ET) is a common movement disorder with ˜5% prevalence in individuals above the age of 65, but in rare cases, it arises during childhood. Growing evidence suggests the role of cerebellum in the disease mechanism. ET is highly heritable, however, poor replication of risk loci point to its significant heterogeneity. Thus, it is important to genetically investigate kindreds with a strong aggregation of ET.
Methods:
We conducted a clinical and whole-genome investigation of a large Caucasian Canadian family, in which six out of eight patients are affected by childhood-onset ET in four consecutive generations. Eight family members were available for study, including three patients affected by ET. Whole-genome sequencing (WGS) was conducted for the four most informative individuals, followed by Sanger sequencing in the entire kindred.
Results:
We searched for rare variants absent in the eldest unaffected individual, but present in the patients (two siblings and their third-degree relative). Our stringent whole-genome filtering approach revealed a rare heterozygous p. Arg90Gln substitution in TCP10L (rs151233771) in all three investigated patients. Sanger sequencing confirmed the p. Arg90Gln variant and revealed its absence in the rest of the family members.
Conclusions:
Whole-genome data of the family with ET resulted in a single candidate gene mapped to 21q22.11 locus (TCP10L) with the highest brain expression in cerebellum. Our study encourages future replication studies to validate the genetic link between TCP10L and ET, and suggests the p. Arg90Gln variant for functional investigation.
The current study investigated associations between variation in the bovine perilipin-2 gene (PLIN2) and milk traits (milk fat content, milk protein content, milk yield and milk fatty acid (FA) component levels) in 409 New Zealand pasture-grazed Holstein-Friesian × Jersey-cross (HF × J-cross or Kiwicross™) cows. Five nucleotide sequence variants were found in three regions of the gene, including c.17C>T in exon 2, c.53A>G in exon 3, c.595+23G>A and c.595+104_595+108del in intron 5, and c.*302T>C in the 3′-untranslated region. The c.*302T>C substitution produces two nucleotide sequence variants (A5 and B5), and this variation was associated with variation in milk protein content and milkfat composition for C10:0, C11:0, C12:0, C13:0 and C16:0 FA and medium-chain fatty acid (MCFA) and long-chain fatty acid (LCFA) groups. After correcting for the effect of variation in the diacylglycerol acyl-CoA acyltransferase 1 gene (DGAT1) that results in the amino acid substitution p.K232A, variation in the FA binding protein 4 gene (FABP4) and variation in the stearoyl-CoA desaturase (Δ-9-desaturase) gene (SCD) that results in the amino acids substitution p.A293V, significant differences between A5A5 and B5B5 cows were found for C10:0, C11:0, C12:0, C13:0, C16:0, and the MCFA, LCFA, total saturated FA and C10:1 index groups. This suggests that nucleotide sequence variation in PLIN2 may be affecting milk FA component levels.
Echinococcus shiquicus is currently limited to the Qinghai–Tibet plateau, a large mountainous region in China. Although the zoonotic potential remains unknown, progress is being made on the distribution and intermediate host range. In this study, we report E. shiquicus within Gansu and Qinghai provinces in regions located not only around the central areas but also the southeast edge of the plateau and describe their genetic relationship with previous isolates from the plateau. From 1879 plateau pikas examined, 2.39% (95% CI 1.79–3.18) were infected with E. shiquicus. The highest prevalence of 10.26% (4.06–23.58) was recorded in Makehe town, Qinghai province. Overall the prevalence was marginally higher in Qinghai (2.5%, CI 1.82–3.43) than in Gansu (2%, CI 1.02–3.89). The cox1 and nad1 genes demonstrated high and low haplotype and nucleotide diversities, respectively. The median-joining network constructed by the cox1–nad1 gene sequences demonstrated a star-like configuration with a median vector (unsampled haplotype) occupying the centre of the network. No peculiar distinction or common haplotype was observed in isolates originating from the different provinces. The presence of E. shiquicus in regions of the southeast and northeast edges of the Qinghai–Tibet plateau and high genetic variation warrants more investigation into the haplotype distribution and genetic polymorphism by exploring more informative DNA regions of the mitochondrial genome to provide epidemiologically useful insight into the population structure of E. shiquicus across the plateau and its axis.
In 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.
Introduced from Europe to North America in the early 19th century as an ornamental shrub and for medicinal purposes, common buckthorn (Rhamnus cathartica L.) has since spread and naturalized throughout regions of the United States and Canada. The purpose of this study was to investigate levels of genetic variation and population differentiation in R.cathartica in its introduced range in North America compared with its native range in Europe to better understand patterns of spread. By analyzing introduced and native populations using microsatellite markers, we found that introduced populations generally exhibited similar or slightly lower levels of genetic variation compared with native populations, consistent with a slight bottleneck effect. Introduced populations contained many different genotypes, indicating genetic admixture, rather than one or few genotypes. In a few cases, populations had been misidentified in the field and were glossy buckthorn (Frangula alnus Mill.; syn. Rhamnus frangula L.). Overall, there was no substantial genetic differentiation detected between native and introduced populations of R. cathartica. Invasive spread in this species is likely due to its past horticultural history as well as adaptive biological traits such as competitive behavior, potential allelopathy, and seed dispersal via birds.
Silverleaf nightshade (Solanum elaeagnifolium Cav.) is an invasive species that has successfully spread outside its native range to become a noxious weed in 21 states in the United States and 42 countries worldwide. The successful establishment of S. elaeagnifolium outside its native habitat indicates its innate ability to adapt to a multitude of environments. Phenotypic plasticity and/or genetic adaptation have been identified as key mechanisms underlying the adaptive success of invasive species. Whereas phenotypic plasticity allows a species to buffer changes in the environment by altering its phenotypic attributes within the short term, genetic adaptation is responsible for the longer-term adaptability of plants to heterogeneous environments and is dependent on the amount of genetic variation present in the species. In this study, we screened DNA markers that are specific to tomato (Solanum lycopersicum L.) and Solanum lycopersicoides Dunal for their interspecific transferability to S. elaeagnifolium and determined the applicability of the transferable DNA markers in assessing the extent of genetic variation in populations from Lubbock, Littlefield, and Blackwell, TX. Of the 187 markers screened, 78 successfully amplified targets in S. elaeagnifolium, indicating the evolutionary conservation of marker loci across S. lycopersicum, S. lycopersicoides, and S. elaeagnifolium, despite their genetic divergence millions of years ago. Genotyping of S. elaeagnifolium populations using 50 DNA markers that consistently amplified clear bands in more than 60% of the plants identified nine polymorphic markers with 0.014 to 0.621 polymorphism information content. Genetic diversity analysis by DNA marker profiling established genetic variation among populations and within individuals of different populations. Unweighted paired group method with arithmetic mean analysis grouped the plants into six clusters that are generally defined by selection pressures unique to each collection site. Results of the study indicate the capacity of S. elaeagnifolium for genetic differentiation in response to variable selection pressures within the same geographic region.
Low temperature is one of the critical factors for determining agricultural production. Therefore, the main objective was to develop the durum wheat lines, which are tolerant to cold particularly in Central Anatolia. The recombinant inbred lines (RILs) (141) derived from F6 progeny of durum wheat, developed from Kunduru-1149 (female parent) and Cham-1 (male parent) cross, were characterized in terms of their cold tolerance both in the field and under controlled (in growth chamber) conditions. A 0–9 scale was used for the visual evaluation of cold damage under field conditions, and a quantitative measure of photochemical efficiency (Fv/Fm = variable fluorescence/maximum fluorescence) method was used for the evaluation of cold damage under controlled conditions. Seventeen RILs displayed the scores within the range of 1–2.5 in 0–9 scale evaluation, while 41 RILs showed the scores equal to or higher than 0.70 approaching to optimal (~0.83) in Fv/Fm evaluation. Some quality parameters tested and some gliadin fragments and random amplified polymorphic DNA loci showed meaningful correlations with the data of 0–9 scale and Fv/Fm ratios from lower to the medium level. The RILs considered as cold resistant; might have the potential to be used as parental lines to develop cold-resistant durum wheat varieties in the future durum wheat-breeding programmes.
Type 2 diabetes, which is caused by both genetic and environmental factors, may be diagnosed using the oral glucose tolerance test (OGTT). Recent studies demonstrated specific patterns in glucose curves during OGTT associated with cardiometabolic risk profiles. As the relative contribution of genetic and environmental influences on glucose curve patterns is unknown, we aimed to investigate the heritability of these patterns. We studied twins from the Danish GEMINAKAR cohort aged 18–67 years and free from diabetes at baseline during 1997–2000; glucose concentrations were measured three times during a 2-h OGTT. Heterogeneity of the glucose response during OGTT was examined with latent class mixed-effects models, evaluating goodness of fit by Bayes information criterion. The genetic influence on curve patterns was estimated using quantitative genetic modeling based on linear structural equations. Overall, 1455 twins (41% monozygotic) had valid glucose concentrations measured from the OGTT, and four latent classes with different glucose response patterns were identified. Statistical modeling demonstrated genetic influence for belonging to a specific class or not, with heritability estimated to be between 45% and 67%. During ∼12 years of follow-up, the four classes were each associated with different incidence of type 2 diabetes. Hence, glucose response curve patterns associated with type 2 diabetes risk appear to be moderately to highly heritable.
This research communication describes associations between variation in the fatty acid binding protein 4 gene (FABP4) and milk fat composition in New Zealand Holstein-Friesian × Jersey cross dairy cows. After correcting for the effect of the amino acid substitution p.K232A in diacylglycerol O-acyltransferase 1 (DGAT1), which is associated with variation in many milk fatty acid (FA) component levels, the effect of FABP4 c.328A/G on milk FA levels was typically small. For the five genotypes analysed, the AB cows produced more medium-chain fatty acids than CC cows (P < 0.05), and more C14:0 FA than AA and AC cows (P < 0.05). The AA and AC cows produced less C22:0 FA (P < 0.01) than the BC cows, and the AC cows produced more C24:0 FA (P < 0.05) than was produced by the BC cows. Cows of genotype CC produce more long-chain fatty acids than cows of genotype BC (P < 0.05).
There is geographical variation in the morphology and genetics of Wuchereria bancrofti, the major cause of human lymphatic filariasis. This study aims to compare morphological and genetic variation of W. bancrofti microfilariae recovered from carriers in Lao PDR, Myanmar and Thailand. Six morphological parameters (body length, cephalic space length and width, length of head to nerve ring, body width at nerve ring, Innenkȍrper length and number of column nuclei between the cephalic space and nerve ring) were evaluated from microfilariae in Giemsa-stained thick blood films. A portion of the cytochrome c oxidase subunit 1 gene of mitochondrial DNA was sequenced and analysed. Wuchereria bancrofti microfilariae showed a wide variation in their morphology and morphometry among three countries. Phylogenetic analysis confirmed that all microfilariae belonged to W. bancrofti. Higher mutation frequencies were observed in samples from Myanmar, relative to Thailand and Lao PDR. This study highlights the morphological disparities of microfilariae and genetic variability within W. bancrofti among three geographical locations. We found that reported morphometric differences between localities were less clear-cut than previously thought. Further studies are needed to determine the microfilarial periodicity in Lao PDR.