Pairs Of Traits Research Articles

Heterosis, Potence Ratio and Correlation of Vegetative, Yield and Quality Traits in Tomato Genotypes and their Performance under Arid Region

Background: The possibility of selecting the best genotypes to develop good hybrid varieties of tomatoes, as well as heterosis, potence ratio and correlation of vegetative characteristics, yield and quality in tomato genotypes and their performance under arid region.Methods: Four commercial tomato cultivars (Money Maker, Pakmore VF, Strain-B and Tanshet Star) and two breeding lines (L05960 and TL01899) and their 15 F1 hybrids, using a half-diallel cross, under arid conditions were used to estimate heterosis, potence ratio and correlation coefficients among all possible pairs of important tomato traits.Result: various degrees of dominance effects for some traits were detected in the general performances of the F1 hybrids, while, other traits illustrated the presence of partial- to under-recessiveness. Heterosis percentages reflected positive desirable effects in ten F1 hybrids for some traits. Most F1 hybrids outperformed their respective parents for fruit set, fruit length, fruit diameter, total soluble solids, fruit dry weight, number of fruits per plant and total fruit yield per plant. Some of the genotypes (i.e., parents and/ or hybrids) offer opportunities as a genetic source of heat tolerant breeding genetic material adapted to high temperature under the arid conditions reported in this study. Significant positive and desirable correlations were found between 41 possible pairs of traits, whereas significant negative and undesirable correlations were found between 13 possible pairs of the traits.

Obesity-Related Traits and the Development of Rheumatoid Arthritis: Evidence From Genetic Data.

ObjectiveTo investigate the association between obesity‐related traits and risk of rheumatoid arthritis (RA).MethodsWe conducted genetic correlation analysis and a 2‐sample Mendelian randomization (MR) study, using genome‐wide genetic data based on >850,000 individuals of European ancestry. Summary statistics were collected from the largest genome‐wide association study conducted to date for body mass index (BMI; n = 806,810), waist‐to‐hip ratio (WHR; n = 697,734), WHR adjusted for BMI (WHRadjBMI; n = 694,649), and RA (ncase = 14,361, ncontrol = 43,923). We conducted cross‐trait linkage disequilibrium score regression and ρ‐HESS analyses to quantify genetic correlation between pairs of traits (causal overlap). For each obesity‐related exposure, we utilized independent, genome‐wide significant single‐nucleotide polymorphisms (P < 5 × 10−9) as instruments to perform MR analysis (causal relationship). We interrogated the causal relationship both in the general population and in a sex‐specific manner and calculated odds ratios (ORs) and 95% confidence intervals (95% CIs). Sensitivity analyses were performed to validate MR model assumptions.ResultsDespite a negligible overall genetic correlation between the 3 obesity‐related traits and RA, we found significant local genetic correlations at several regions on chromosome 6 (positions 28–29M, 30–35M, and 50–52M), highlighting a shared genetic basis. We further observed an increased risk of RA per SD increment (4.8 kg/m2) in genetically predicted BMI (OR 1.22 [95% CI 1.09–1.37]). The effect was consistent across sensitivity analyses and comparable between sexes (OR 1.22 [95% CI 1.04–1.44] in male subjects and 1.19 [95% CI 1.04–1.36] in female subjects). However, we did not find evidence supporting a causal role of either WHR (OR 0.98 [95% CI 0.84–1.14]) or WHRadjBMI (OR 0.90 [95% CI 0.79–1.04]) in RA.ConclusionGenetically predicted BMI significantly increases RA risk. Future studies are needed to understand the biologic mechanisms underlying this link.

Variations in reproductive and egg traits correlation estimates of two strains of Archachatina marginata snails (var. ovum and var. saturalis) and crosses

A study was conducted to ariations in the reproductive traits and egg traitscorrelation estimates of the two strains of Archachatina marginata snails (var. ovum and var. saturalis) and their crosses. Ninety sexually mature A. marginata snails, forty-five each of the two strains (var. saturalis and var. ovum) were selected from a base population for the study. he live weight of the snails ranged from 256.43 – 566.25 g for both strains. Selection of the snails was based on active appearance and lack of injury on the foot and on shells. The snails were randomly allotted into three mating models (treatments) of 30 each of var. saturalis, var. ovum and mixed strains (at 15 var. ovum : 15 var. saturalis). The models were designated as homozygous var. ovum main cross (AMO X AMO), homozygous var. saturalis main cross (AMS X AMS) and heterozygous (var. ovum x var. saturalis) cross (AMO X AMS). Each of the three models was replicated 15 times with two snails to a tub/cell for purposes of reproduction. Results from the study showed that the three mating models expressed significant (P&lt;0.05) differences in the reproductive traits evaluated. Whereas some of the traits were not significantly (P&gt;0.05) different between the AMO X AMO and AMO X AMS mating models, significant (P&lt;0.05) differences existed between all the traits when the AMS AMS mating model was compared with the AMO X AMO and AMO X AMS mating models. The clutch size ranged from 7.00±0.35 (AMS X AMS) through 9.40±0.35 (AMO X AMS) to 9.90±0.35 (AMO X AMO), while the values for mean egg weight at lay ranged from 1.59±0.03 g (AMS X AMS) through 1.78±0.03 g (AMO X AMO) to 1.79±0.03 g (AMO X AMS). Percent hatchability value was highest in the AMO X AMO mating model (93.30 %), followed by the AMS X AMS mating model (91.10 %), while the AMO X AMS mating model recorded the lowest value (88.50 %). Percent survivability value was highest in the AMO X AMS mating model (84.00 %), followed by the AMO X AMO mating model (82.00 %), while the AMS X AMS mating model recorded the lowest value (80.00 %). The egg traits correlation estimates (rp) revealed that except for one pair of trait each in the mating models, all the other pairs of traits expressed positive and significant correlation coefficients/values. The AMO X AMS mating model recorded the highest correlation (rp) value (0.826) for the pair of ELH vs EWH, while the AMS X AMS mating model recorded the lowest correlation (rp) value (– 0.058) for the pair of ELH vs CSE. The percent egg shell colour distribution showed that the shell of eggs laid by the homozygous crosses (AMO X AMO and AMS X AMS) expressed two colours. The egg shell of eggs laid by AMO X AMO mating model expressed mikado yellowand maize yellow colours, while those laid by AMS X AMS mating model expressed Mikado yellow and amber colours. The shell of eggs laid by the heterozygous cross however expressed three colours; mikado yellow, maize yellow and amber. Based on the reproductive traits results, it could be recommended that the AMO X AMS mating model be adopted by farmers for optimum production and returns on investment.

Correlation, regression estimates and heterosis of Archachatina marginata snails in Calabar, Nigeria

White skinned ectotypes were used in a study to estimate heterosis, correlation and regression. Data collected on the snails and their eggs included body weight (BWT), shell length (SLH), shell width (SWH), “mouth” length (MLH) and “mouth” width (MWH); and egg weight (EWT), egg length (ELH) and egg width (EWH), respectively. These data were used to estimate correlations between pairs of traits, heterosis and to predict weight from other morphometric traits among three mating groups [black skinned x black skinned (BAM X BAM), white skinned x white skinned (WAM X WAM) and their cross BAM X WAM)]. Results obtained from the study showed that evaluated traits expressed strong, positive and highly significant (P&lt;0.01) correlation values that ranged from rp= 0.86 to rp = 0.99 among the snails mating groups. The correlation values of traits evaluated on eggs laid by these snails ranged from mild (rp = 0.49) through moderate (rp = 0.59, rp= 0.70) to strong/close (rp = 0.89). Regression estimates values obtained ranged from mild (1.30) to high (6.25), an shell width best predicted hatchlings body weight in the black skinned x black skinned (BAM X BAM) mating group, while “mouth” length best predicted hatchlings body weight in the white skinned x white skinned (WAM X WAM) mating group. Traits evaluated for percent heterosis expressed positive and significant (P&lt;0.05) values between the mating groups, with the crossbred (BAM X WAM) mating group having advantage over the purebred (BAM X BAM and WAM X WAM) mating groups. It could therefore be concluded that in the face of appropriate selection programme, heterosis can be exploited to improve snails reproductive and growth traits. It can thus be recommended that having information regarding the association of weight with other contributing traits/parameters is crucial before starting any breeding programme.

Genetic parameters and purebred-crossbred genetic correlations for growth, meat quality, and carcass traits in pigs.

Growth, meat quality, and carcass traits are of economic importance in swine breeding. Understanding their genetic basis in purebred (PB) and commercial crossbred (CB) pigs is necessary for a successful breeding program because, although the breeding goal is to improve CB performance, phenotype collection and selection are usually carried out in PB populations housed in biosecure nucleus herds. Thus, the selection is indirect, and the accuracy of selection depends on the genetic correlation between PB and CB performance (rpc). The objectives of this study were to 1) estimate genetic parameters for growth, meat quality, and carcass traits in a PB sire line and related commercial CB pigs and 2) estimate the corresponding genetic correlations between purebred and crossbred performance (rpc). Both objectives were investigated by using pedigree information only (PBLUP) and by combining pedigree and genomic information in a single-step genomic BLUP (ssGBLUP) procedure. Growth rate showed moderate estimates of heritability for both PB and CB based on PBLUP, while estimates were higher in CB based on ssGBLUP. Heritability estimates for meat quality traits were diverse and slightly different based on PB and CB data with both methods. Carcass traits had higher heritability estimates based on PB compared with CB data based on PBLUP and slightly higher estimates for CB data based on ssGBLUP. A wide range of estimates of genetic correlations were obtained among traits within the PB and CB data. In the PB population, estimates of heritabilities and genetic correlations were similar based on PBLUP and ssGBLUP for all traits, while based on the CB data, ssGBLUP resulted in different estimates of genetic parameters with lower SEs. With some exceptions, estimates of rpc were moderate to high. The SE on the rpc estimates was generally large when based on PBLUP due to limited sample size, especially for CBs. In contrast, estimates of rpc based on ssGBLUP were not only more precise but also more consistent among pairs of traits, considering their genetic correlations within the PB and CB data. The wide range of estimates of rpc (less than 0.70 for 7 out of 13 traits) indicates that the use of CB phenotypes recorded on commercial farms, along with genomic information, for selection in the PB population has potential to increase the genetic progress of CB performance.

The acquisitive-conservative axis of leaf trait variation emerges even in homogeneous environments.

The acquisitive-conservative axis of plant ecological strategies results in a pattern of leaf trait covariation that captures the balance between leaf construction costs and plant growth potential. Studies evaluating trait covariation within species are scarcer, and have mostly dealt with variation in response to environmental gradients. Little work has been published on intraspecific patterns of leaf trait covariation in the absence of strong environmental variation. We analysed covariation of four leaf functional traits [specific leaf area (SLA) leaf dry matter content (LDMC), force to tear (Ft) and leaf nitrogen content (Nm)] in six Poaceae and four Fabaceae species common in the dry Chaco forest of Central Argentina, growing in the field and in a common garden. We compared intraspecific covariation patterns (slopes, correlation and effect size) of leaf functional traits with global interspecific covariation patterns. Additionally, we checked for possible climatic and edaphic factors that could affect the intraspecific covariation pattern. We found negative correlations for the LDMC-SLA, Ft-SLA, LDMC-Nm and Ft-Nm trait pairs. This intraspecific covariation pattern found both in the field and in the common garden and not explained by climatic or edaphic variation in the field follows the expected acquisitive-conservative axis. At the same time, we found quantitative differences in slopes among different species, and between these intraspecific patterns and the interspecific ones. Many of these differences seem to be idiosyncratic, but some appear consistent among species (e.g. all the intraspecific LDMC-SLA and LDMC-Nm slopes tend to be shallower than the global pattern). Our study indicates that the acquisitive-conservative leaf functional trait covariation pattern occurs at the intraspecific level even in the absence of relevant environmental variation in the field. This suggests a high degree of variation-covariation in leaf functional traits not driven by environmental variables.

Inferring causal direction between two traits in the presence of horizontal pleiotropy with GWAS summary data.

Orienting the causal relationship between pairs of traits is a fundamental task in scientific research with significant implications in practice, such as in prioritizing molecular targets and modifiable risk factors for developing therapeutic and interventional strategies for complex diseases. A recent method, called Steiger’s method, using a single SNP as an instrument variable (IV) in the framework of Mendelian randomization (MR), has since been widely applied. We report the following new contributions. First, we propose a single SNP-based alternative, overcoming a severe limitation of Steiger’s method in simply assuming, instead of inferring, the existence of a causal relationship. We also clarify a condition necessary for the validity of the methods in the presence of hidden confounding. Second, to improve statistical power, we propose combining the results from multiple, and possibly correlated, SNPs as multiple instruments. Third, we develop three goodness-of-fit tests to check modeling assumptions, including those required for valid IVs. Fourth, by relaxing one of the three IV assumptions in MR, we propose several methods, including an Egger regression-like approach and its multivariable version (analogous to multivariable MR), to account for horizontal pleiotropy of the SNPs/IVs, which is often unavoidable in practice. All our methods can simultaneously infer both the existence and (if so) the direction of a causal relationship, largely expanding their applicability over that of Steiger’s method. Although we focus on uni-directional causal relationships, we also briefly discuss an extension to bi-directional relationships. Through extensive simulations and an application to infer the causal directions between low density lipoprotein (LDL) cholesterol, or high density lipoprotein (HDL) cholesterol, and coronary artery disease (CAD), we demonstrate the superior performance and advantage of our proposed methods over Steiger’s method and bi-directional MR. In particular, after accounting for horizontal pleiotropy, our method confirmed the well known causal direction from LDL to CAD, while other methods, including bi-directional MR, might fail.

Genomic Heritabilities and Correlations of 17 Traits Related to Obesity and Associated Conditions in the Japanese Population.

Over the past few decades, obesity has become a public health issue of global concern. Even though disparities exist between human populations, e.g., the higher liver fat content of the Japanese despite a lower body mass index (BMI), studies on the genetics of obesity still largely focus on populations of European descent, leading to a dearth of genetic data on non-European populations. In this context, this study aimed to establish a broad picture of the genetic attributes of the Japanese population, by examining a representative sample of 18,889 individuals participating in the Tohoku Medical Megabank Project cohort. We applied linear mixed model methods to 17 traits related to obesity and associated diseases to estimate the heritabilities explained by common genetic variants and the genetic correlations between each pair of traits. These analyses allowed us to quantify the SNP heritability of health indicators such as BMI (0.248 ± 0.032) and HDL cholesterol (0.324 ± 0.031), and to provide one of the few estimates of the SNP heritability of cystatin C in unrelated individuals (0.260 ± 0.025). We discuss potential differences between the Japanese and people of European ancestry with respect to the genetic correlations between urinary biomarkers and adiposity traits, for which large estimates were obtained. For instance, the genetic correlations between urine potassium level and the values for weight, BMI, waist circumference, and waist-to-height ratio ranged from 0.290 to 0.559, much higher than the corresponding estimates in the UK Biobank.

Selection of water harvesting sites in Horan valley

Geographic techniques were used to select the sites of water harvesting systems within the Horan basin. Analytical Hierarchy Process (AHP) and pairwise comparison were used to determine the importance of selected traits for water harvesting (soil texture area, runoff, Land cover,). A total of 96 water harvesting sites were identified, of which 11 were found to be the most important. The results showed that the use of AHP to compare the pairs of traits affecting water harvesting. There are several promising areas for harvesting, totaling 96 sites, distributed between sandy and loamy sand and sandy clay loam. With 11 sites characterized by sandy clay soil and high surface runoff. The site 41 has the highest weight in the selected traits 0.557, while the site 84 was the lowest weight and reached 0.339 in terms of importance. The total area of the 96 study sites reached 35402.48 ha, which constitutes 19.7% of the area of the valley, while the area of the most important sites for harvesting, which amounted to 11 sites (633.49) ha, which constitutes (0.35%) of Total area of the valley and 1.7% of the total area of the water harvesting sites. The volume of water collected at all harvest sites (96 sites) was 20288131.92 m3, 567159.58 m3. The correlation between the different characteristics, the derivation of a mathematical equation that reflects the values of the best sites using a program, and then a map of calculated values, is calculated to determine their suitability in the application.

Screening for Drought Tolerance in Maize (Zea mays L.) Germplasm Using Germination and Seedling Traits under Simulated Drought Conditions.

Maize is known to be susceptible to drought stress, which negatively affects vegetative growth and biomass production, as well as the formation of reproductive organs and yield parameters. In this study, 27 responsive traits of germination (G) and seedlings growth were evaluated for 40 accessions of the Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) germplasm collection, under no stress and simulated drought stress treatments by 10%, 15%, and 20% of polyethylene glycol (PEG). The three treatments significantly reduced G% and retarded seedlings growth, particularly the 15% and 20% PEG treatments; these two treatments also resulted in a significant increase of abnormal seedlings (AS). The heritability (H2) and correlations of the traits were estimated, and drought tolerance indices (DTIs) were calculated for traits and accessions. The H2 of G% values were reduced, and H2 for AS% increased as the PEG stress increased. Positive correlations were found between most trait pairs, particularly shoot and root traits, with 48 highly significant correlations under no stress and 25 highly significant correlations under the 10% PEG treatments, particularly for shoot and root traits. The medium to high heritability of shoot and root seedling traits provides a sound basis for further genetic analyses. PCA analysis clearly grouped accessions with high DTIs together and the accessions with low DTIs together, indicating that the DTI indicates the stress tolerance level of maize germplasm. However, the resemblance in DTI values does not clearly reflect the origin or taxonomic assignments to subspecies and varieties of the examined accessions.

Nausea and Vomiting of Pregnancy and HG Risk Genes Associated With Blood Levels, Sleep, Stomach Pain, and Other Traits [23N

INTRODUCTION: Our genome-wide association study (GWAS) and replication study of nausea and vomiting of pregnancy (NVP) and Hyperemesis Gravidarum (HG) implicates the placenta and appetite hormone gene GDF15, its receptor GFRAL, PGR, and IGFBP7. The purpose of this study was to determine whether these genes and summary statistics overlap with other traits. METHODS: The GWAS catalog was searched for risk genes. The database and web interface platform, LD Hub, was used for genetic correlation analysis of summary statistics. RESULTS: Among 4220 GWASes, the HG risk locus GDF15 was associated with GDF15 protein levels, periodontitis, and lupus. GFRAL was associated with glomerular filtration rate, blood urea nitrogen levels, insomnia, body mass index, periodontal inflammation, blood protein levels, osteoporosis, and HIV-1 infection. IGFBP7 was associated with IGFBP7 protein levels, IgG glycosylation, diastolic blood pressure, brain volume in infants, heel bone mineral density, alcohol consumption, itch intensity from mosquitoes, and cotinine glucuronidation. PGR was associated with diastolic blood pressure, endometriosis/endometrial cancer, menstrual cycle length, lung adenocarcinoma, height, and adolescent idiopathic scoliosis. Among 855 pairs of traits, the leading findings showed variants increasing HG also increase stomach pain (P=.0004) and variants increasing NVP also increase sleeplessness/insomnia (P=1.37E-14). CONCLUSION: The finding that variants in GDF15 and IGFBP7 are associated with blood protein levels supports our study showing abnormal levels of GDF15 and IGFBP7 in women with HG. Overlap of the genes with other conditions provides biological insight. Associations with poor sleep and stomach pain may have implications for treatment strategies for NVP/HG.

Shared genetic architecture and casual relationship between leptin levels and type 2 diabetes: large-scale cross-trait meta-analysis and Mendelian randomization analysis

ObjectiveWe aimed to estimate genetic correlation, identify shared loci and test causality between leptin levels and type 2 diabetes (T2D).Research design and methodsOur study consists of three parts. First, we...

Investigating the genetic and causal relationship between initiation or use of alcohol, caffeine, cannabis and nicotine

BackgroundCaffeine, alcohol, nicotine and cannabis are commonly used psychoactive substances. While the use of these substances has been previously shown to be genetically correlated, causality between these substance use traits remains unclear. We aimed to revisit the genetic relationships among different measures of SU using genome-wide association study (GWAS) summary statistics from the UK Biobank, International Cannabis Consortium, and GWAS & Sequencing Consortium of Alcohol and Nicotine use. MethodsWe obtained GWAS summary statistics from the aforementioned consortia for ten substance use traits including various measures of alcohol consumption, caffeine consumption, cannabis initiation and smoking behaviours. We then conducted SNP-heritability (h2) estimation for individual SU traits, followed by genetic correlation analyses and two-sample Mendelian randomisation (MR) studies between substance use trait pairs. ResultsSNP h2 of the ten traits ranged from 0.03 to 0.11. After multiple testing correction, 29 of the 45 trait pairs showed evidence of being genetically correlated. MR analyses revealed that most SU traits were not causally associated with each other. However, we found evidence for an MR association between regular smoking initiation and caffeine consumption 40.17 mg; 95 % CI: [24.01, 56.33] increase in caffeine intake per doubling of odds in smoking initiation). Our findings were robust against horizontal pleiotropy, SNP-outliers, and the direction of causality was consistent in all MR analyses. ConclusionsMost of the substance traits were genetically correlated but there is little evidence to establish causality apart from the relationship between smoking initiation and caffeine consumption.

Empirical comparisons of multiple Mendelian randomization approaches in the presence of assortative mating.

BackgroundMendelian randomization (MR) is widely used to unravel causal relationships in epidemiological studies. Whereas multiple MR methods have been developed to control for bias due to horizontal pleiotropy, their performance in the presence of other sources of bias, like non-random mating, has been mostly evaluated using simulated data. Empirical comparisons of MR estimators in such scenarios have yet to be conducted. Pleiotropy and non-random mating have been shown to account equally for the genetic correlation between height and educational attainment. Previous studies probing the causal nature of this association have produced conflicting results.MethodsWe estimated the causal effect of height on educational attainment in various MR models, including the MR-Egger and the MR-Direction of Causation (MR-DoC) models that correct for, or explicitly model, horizontal pleiotropy.ResultsWe reproduced the weak but positive association between height and education in the Netherlands Twin Register sample (P= 3.9 × 10–6). All MR analyses suggested that height has a robust, albeit small, causal effect on education. We showed via simulations that potential assortment for height and education had no effect on the causal parameter in the MR-DoC model. With the pleiotropic effect freely estimated, MR-DoC yielded a null finding.ConclusionsNon-random mating may have a bearing on the results of MR studies based on unrelated individuals. Family data enable tests of causal relationships to be conducted more rigorously, and are recommended to triangulate results of MR studies assessing pairs of traits leading to non-random mate selection.

Genetic overlap between psychotic experiences in the community across age and with psychiatric disorders

This study explores the degree to which genetic influences on psychotic experiences are stable across adolescence and adulthood, and their overlap with psychiatric disorders. Genome-wide association results were obtained for adolescent psychotic experiences and negative symptom traits (N = 6297–10,098), schizotypy (N = 3967–4057) and positive psychotic experiences in adulthood (N = 116,787–117,794), schizophrenia (N = 150,064), bipolar disorder (N = 41,653), and depression (N = 173,005). Linkage disequilibrium score regression was used to estimate genetic correlations. Implicated genes from functional and gene-based analyses were compared. Mendelian randomization was performed on trait pairs with significant genetic correlations. Results indicated that subclinical auditory and visual hallucinations and delusions of persecution during adulthood were significantly genetically correlated with schizophrenia (rg = 0.27–0.67) and major depression (rg = 0.41–96) after correction for multiple testing. Auditory and visual subclinical hallucinations were highly genetically correlated (rg = 0.95). Cross-age genetic correlations for psychotic experiences were not significant. Gene mapping and association analyses revealed 14 possible genes associated with psychotic experiences that overlapped across age for psychotic experiences or between psychotic experiences and psychiatric disorders. Mendelian randomization indicated bidirectional associations between auditory and visual hallucinations in adults but did not support causal relationships between psychotic experiences and psychiatric disorders. These findings indicate that psychotic experiences in adulthood may be more linked genetically to schizophrenia and major depression than psychotic experiences in adolescence. Our study implicated specific genes that are associated with psychotic experiences across development, as well as genes shared between psychotic experiences and psychiatric disorders.

Mediterranean nekton traits: distribution, relationships and significance for marine ecology monitoring and management.

Biological traits are increasingly used in order to study aspects of ecology as they are related to the organisms’ fitness. Here we analyze a dataset of 23 traits regarding the life cycle, distribution, ecology and behavior of 235 nektonic species of the Mediterranean Sea in order to evaluate the distribution of traits, identify rare ones, detect relationships between trait pairs and identify species functional groups. Trait relationships were tested using correlation and non-linear regression for continuous traits, parametric and non-parametric inference tests for pairs of continuous-categorical traits and cooccurrence testing for categorical traits. The findings have significant implications concerning the potential effects of climate change (e.g., through the relationships of the trait of optimal temperature), fisheries or habitat loss (from the relationships of traits related to tolerance ranges). Furthermore, some unexpected relationships are documented, like the inversely proportional relationship between longevity and age at maturity as a percentage of life span. Associations between functional traits show affinities derived from phylogenetic constraints or life strategies; however, relationships among functional and ecological traits can indicate the potential environmental filtering that acts on functional traits. In total, 18 functional groups were identified by Hill-Smith ordination and hierarchical clustering and were characterized by their dominant traits. For the assessment of the results, we first evaluate the importance of each trait at the level of population, community, ecosystem and landscape and then propose the traits that should be monitored for the regulation and resilience of ecosystem functioning and the management of the marine ecosystems.

Variant forms of qualitative traits of indigenous chickens reared under extensive system in Tolon District, Ghana

Context Rural chicken production in most developing countries is based mainly on scavenging systems with indigenous chickens that have not been properly characterised and classified into well-defined breeds. Aims This study was conducted to identify the variant forms of qualitative phenotypic traits of local chickens in Tolon District, northern Ghana. Methods About 320 adult birds were sampled and data collected by using observation and a chicken colour chart. Traits included head shape; comb type, size and colour; feather distribution; and earlobe, eye, plumage, skin and shank colours. Chi-squared goodness of fit test was used to test whether variant phenotypes of each qualitative trait were equally distributed. The hypothesis of no associations between pairs of traits was tested by using Cramér’s V. Key results There were highly significant (P &amp;lt; 0.01) differences in the distributions of variant phenotypes of all traits. The main comb type observed was single (85.9%), followed by pea (8.8%) and rose (5.3%). A majority of birds had small combs (57.8%), although others had medium (28.4%) and large (13.8%) combs. Females had small to medium combs, whereas males had medium to large combs. A majority of the chickens had white earlobe colour (60.3%), followed by pied red and white (22.5%). Feather distributions observed were normal feathered (84.4%), naked neck (8.4%) and frizzled (7.2%). Five plumage colours were observed, although some were in combinations. White plumage was the most common (22.5%), followed by black (18.8%), with brown/ash the least common (0.03%). Community was significantly (P &amp;lt; 0.01) associated with comb type, size and colour, and eye, shank and skin colours. Also, comb size was significantly associated with sex and comb type. Conclusions Generally, local chickens exhibited heterogynous phenotypes for qualitative traits. Local chickens in the district could be described as normally feathered with wide variation in plumage colours and having mainly single comb type. Implications The knowledge of these variant phenotypes and their associations will serve as baseline information for the characterisation and conservation of local chicken types. It could also provide guidelines in selecting bird ecotypes and/or communities for breed improvement programs in the study area.

Genetic analysis of activity, brain and behavioral associations in extended families with heavy genetic loading for bipolar disorder.

Disturbed sleep and activity are prominent features of bipolar disorder type I (BP-I). However, the relationship of sleep and activity characteristics to brain structure and behavior in euthymic BP-I patients and their non-BP-I relatives is unknown. Additionally, underlying genetic relationships between these traits have not been investigated. Relationships between sleep and activity phenotypes, assessed using actigraphy, with structural neuroimaging (brain) and cognitive and temperament (behavior) phenotypes were investigated in 558 euthymic individuals from multi-generational pedigrees including at least one member with BP-I. Genetic correlations between actigraphy-brain and actigraphy-behavior associations were assessed, and bivariate linkage analysis was conducted for trait pairs with evidence of shared genetic influences. More physical activity and longer awake time were significantly associated with increased brain volumes and cortical thickness, better performance on neurocognitive measures of long-term memory and executive function, and less extreme scores on measures of temperament (impulsivity, cyclothymia). These associations did not differ between BP-I patients and their non-BP-I relatives. For nine activity-brain or activity-behavior pairs there was evidence for shared genetic influence (genetic correlations); of these pairs, a suggestive bivariate quantitative trait locus on chromosome 7 for wake duration and verbal working memory was identified. Our findings indicate that increased physical activity and more adequate sleep are associated with increased brain size, better cognitive function and more stable temperament in BP-I patients and their non-BP-I relatives. Additionally, we found evidence for pleiotropy of several actigraphy-behavior and actigraphy-brain phenotypes, suggesting a shared genetic basis for these traits.

Deciphering the Biological Mechanisms Underlying the Genome-Wide Associations between Computerized Device Use and Psychiatric Disorders.

Computerized device use (CDU) is societally ubiquitous but its effects on mental health are unknown. We performed genetic correlation, Mendelian randomization, and latent causal variable analyses to identify shared genetic mechanisms between psychiatric disorders (Psychiatric Genomics Consortium; 14,477 < N < 150,064) and CDU (UK Biobank; N = 361,194 individuals). Using linkage disequilibrium score regression, we detected strong genetic correlations between “weekly usage of mobile phone in last 3 months” (PhoneUse) vs. attention deficit hyperactivity disorder (ADHD; rg = 0.425, p = 4.59 × 10−29) and “plays computer games” (CompGaming) vs. schizophrenia (SCZ; rg = −0.271, p = 7.16 × 10−26). Focusing on these correlations, we used two sample MRs to detect the causal relationships between trait pairs by treating single nucleotide polymorphisms as non-modifiable risk factors underlying both phenotypes. Significant bidirectional associations were detected (PhoneUse→ADHD β = 0.132, p = 1.89 × 10−4 and ADHD→PhoneUse β = 0.084, p = 2.86 × 10−10; CompGaming→SCZ β = −0.02, p = 6.46 × 10−25 and CompGaming→SCZ β = −0.194, p = 0.005) and the latent causal variable analyses did not support a causal relationship independent of the genetic correlations between these traits. This suggests that molecular pathways contribute to the genetic overlap between these traits. Dopamine transport enrichment (Gene Ontology:0015872, pSCZvsCompGaming = 2.74 × 10−10) and DRD2 association (pSCZ = 7.94 × 10−8; pCompGaming = 3.98 × 10−25) were detected in SCZ and CompGaming and support their negative correlative relationship. FOXP2 was significantly associated with ADHD (p = 9.32 × 10−7) and PhoneUse (p = 9.00 × 10−11) with effect directions concordant with their positive genetic correlation. Our study demonstrates that epidemiological associations between psychiatric disorders and CDUs are due, in part, to the molecular mechanisms shared between them rather than a causal relationship. Our findings imply that biological mechanisms underlying CDU contribute to the psychiatric phenotype manifestation.

CRITERIA OF THE CULTIVAR MODEL AND INTERRELATIONS AMONG ECONOMICALLY USEFUL CHARACTERISTICS OF CHAENOMELES IN CONNECTION WITH BREEDING

Background. Chaenomeles Lindl. is a popular ornamental and relatively young fruit crop. Genetic diversity of the genus favors breeding not only in these two areas, but also aiming at the development of cultivars of a universal type. To improve the efficiency of the breeding process, a cultivar model with the maximum combination of useful qualities in one genotype is vitally needed. The goal of this work was to identify the criteria for the model of a universal Chaenomeles cultivar, select cultivars that come closest to the model in their main economic traits, and find relationships among such characteristics. Materials and methods. The study engaged 21 Chaenomeles cultivars and forms selected for their valuable qualities from the Nikita Botanical Gardens collection. They were compared with the cultivar model using cluster analysis, while correlation analysis was employed to assess interrelations between traits. Results and conclusion. Criteria were identified for the universal cultivar model of Chaenomeles (ornamental and fruit purposes) according to 27 characteristics. Seven genotypes turned out to be closest to the universal model in a set of traits (4.44 units of the Euclidean distance): PХ4/9 (4.25 units), ‘Samurai’ (4.15 units), ‘Araks’ (4.01 units), ‘Afrikanych’, ‘Shatenka’ (3.9 units), ‘Krasavitsa Madlen’ and ‘Rosemary’ (3.7 units). Different degrees of correlation between the main 17 characteristics were observed. The strongest relationships was found between the beginning of flowering and its duration (r = –0.9), between the beginning of flowering and the duration of the dormancy period (r = 0.91), between the durations of flowering and dormancy periods (r = –0.82), between the corolla diameter, the flower’s originality (r = 0.83) and the overall ornamentality of the bush (r = 0.86). A tendency to dependence was observed in 12 pairs of traits (r = 0.46 to 0.61).