Levels of genetic polymorphism: marker loci versus quantitative traits

Species are the units used to measure ecological diversity and alleles are the units of genetic diversity. Genetic variation within and among species has been documented most extensively using allozyme electrophoresis. This reveals wide differences in genetic variability within, and genetic distances among, species, demonstrating that species are not equivalent units of diversity. The extent to which the pattern observed for allozymes can be used to infer patterns of genetic variation in quantitative traits depends on the forces generating and maintaining variability. Allozyme variation is probably not strictly neutral but, nevertheless, heterozygosity is expected to be influenced by population size and genetic distance will be affected by time since divergence. The same is true for quantitative traits influenced by many genes and under weak stabilizing selection. However, the limited data available suggest that allozyme variability is a poor predictor of genetic variation in quantitative traits within populations. It is a better predictor of general phenotypic divergence and of postzygotic isolation between populations or species, but is only weakly correlated with prezygotic isolation. Studies of grasshopper and planthopper mating signal variation and assortative mating illustrate how these characters evolve independently of general genetic and morphological variation. The role of such traits in prezygotic isolation, and hence speciation, means that they will contribute significantly to the diversity of levels of genetic variation within and among species

Genomic and phenotypic analysis of Vavilov's historic landraces reveals the impact of environment and genomic islands of agronomic traits.

The Vavilov Institute of Plant Genetic Resources (VIR), in St. Petersburg, Russia, houses a unique genebank, with historical collections of landraces. When they were collected, the geographical distribution and genetic diversity of most crops closely reflected their historical patterns of cultivation established over the preceding millennia. We employed a combination of genomics, computational biology and phenotyping to characterize VIR's 147 chickpea accessions from Turkey and Ethiopia, representing chickpea's center of origin and a major location of secondary diversity. Genotyping by sequencing identified 14,059 segregating polymorphisms and genome-wide association studies revealed 28 GWAS hits in potential candidate genes likely to affect traits of agricultural importance. The proportion of polymorphisms shared among accessions is a strong predictor of phenotypic resemblance, and of environmental similarity between historical sampling sites. We found that 20 out of 28 polymorphisms, associated with multiple traits, including days to maturity, plant phenology, and yield-related traits such as pod number, localized to chromosome 4. We hypothesize that selection and introgression via inadvertent hybridization between more and less advanced morphotypes might have resulted in agricultural improvement genes being aggregated to genomic 'agro islands', and in genotype-to-phenotype relationships resembling widespread pleiotropy

The relevance of schizotypal traits for understanding interpersonal functioning in adolescents with psychiatric problems.

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Normal and Abnormal Personality Traits are Associated with Marital Satisfaction for both Men and Women: An Actor–Partner Interdependence Model Analysis

Research has demonstrated associations between relationship satisfaction and personality traits. Using the Actor–Partner Interdependence Model, we explored associations between self-reported relationship satisfaction in couples (n = 118) and various measures of normal and abnormal personality, including higher-order dimensions of PE/Extraversion, NE/Neuroticism, Constraint (CON), and their lower-order facets. We also examined gender differences and moderators of associations. Consistent with the Vulnerability Stress Adaptation Model, self- and partner-reported NE and PE were related to satisfaction, and their lower-order traits demonstrated differential associations with satisfaction. Further, abnormal personality traits specific to the interpersonal domain and personality disorder symptoms demonstrated effects. Relationship length emerged as a significant moderator, with associations weakening as relationship duration increased

Unwanted pursuit behavior after breakup: occurrence, risk factors, and gender differences

This study investigated unwanted pursuit behavior (UPB) perpetration in 631 adult ex-partners. UPB involves the unwanted pursuit of intimacy, a widespread and usually less severe form of stalking. The occurrence and various risk factors of UPB perpetration were examined, accounting for differences between male and female ex-partners and same- and opposite-gender ex-partners. Ex-partners showed on average five to six UPBs after their separation. Male and female and same- and opposite-gender ex-partners displayed an equal number of UPBs. The number of perpetrated UPBs was explained by breakup characteristics (ex-partner initiation of the breakup and rumination or cognitive preoccupation with the ex-partner), relationship characteristics (anxious attachment in the former relationship), and individual perpetrator characteristics (borderline traits and past delinquent behaviors). Rumination was a stronger predictor in female than male ex-partners. Borderline traits and anxious attachment positively predicted UPB perpetration in opposite-gender but not in same-gender ex-partners. Implications of these findings are discussed

ASSESSING THE RELATIVE INFLUENCES OF ABIOTIC AND BIOTIC FACTORS ON A SPECIES’ DISTRIBUTION USING PSEUDO-ABSENCE AND FUNCTIONAL TRAIT DATA: A CASE STUDY WITH THE AMERICAN EEL (Anguilla rostrata)

Species’ distributions are influenced by abiotic and biotic factors but direct comparison of their relative importance is difficult, particularly when working with complex, multi-species datasets. Here, we present a flexible method to compare abiotic and biotic influences at common scales. First, data representing abiotic and biotic factors are collected using a combination of geographic information system, remotely sensed, and species’ functional trait data. Next, the relative influences of each predictor variable on the occurrence of a focal species are compared. Specifically, ‘sample’ data from sites of known occurrence are compared with ‘background’ data (i.e. pseudo-absence data collected at sites where occurrence is unknown, combined with sample data). Predictor variables that may have the strongest influence on the focal species are identified as those where sample data are clearly distinct from the corresponding background distribution. To demonstrate the method, effects of hydrology, physical habitat, and co-occurring fish functional traits are assessed relative to the contemporary (1950 – 1990) distribution of the American Eel (Anguilla rostrata) in six Mid-Atlantic (USA) rivers. We find that Eel distribution has likely been influenced by the functional characteristics of co-occurring fishes and by local dam density, but not by other physical habitat or hydrologic factors

Fetal testosterone and autistic traits

Studies of amniotic testosterone in humans suggest that fetal testosterone (fT) is related to specific (but not all) sexually dimorphic aspects of cognition and behaviour. It has also been suggested that autism may be an extreme manifestation of some male-typical traits, both in terms of cognition and neuroanatomy. In this paper, we examine the possibility of a link between autistic traits and fT levels measured in amniotic fluid during routine amniocentesis. Two instruments measuring number of autistic traits (the Childhood Autism Spectrum Test (CAST) and the Child Autism Spectrum Quotient (AQ-Child)) were completed by these women about their children (N = 235), ages 6-10 years. Intelligence Quotient (IQ) was measured in a subset of these children (N = 74). fT levels were positively associated with higher scores on the CAST and AQ-Child. This relationship was seen within sex as well as when the sexes were combined, suggesting this is an effect of fT rather than of sex per se. No relationships were found between overall IQ and the predictor variables, or between IQ and CAST or AQ-Child. These findings are consistent with the hypothesis that prenatal androgen exposure is related to children exhibiting more autistic traits. These results need to be followed up in a much larger sample to test if clinical cases of ASC have elevated fT.</p

The relationships between personality, approaches to learning, and academic success in first-year psychology distance education students

[Abstract]: The first aim of this study was to examine the relationships between the big five personality traits and approaches to learning in a sample of first-year psychology distance students. Approaches to learning are the intentions a student has when faced with a learning task. A deep approach reflects an intention to understand the material, a strategic approach reflects an intention to achieve the highest grades possible, and a surface approach reflects an intention to cope with the course requirements by memorising facts. Consistent with previous research of on-campus students, the Intellect trait predicted the deep learning approach; the Conscientiousness trait predicted the strategic learning approach; and the Emotional Stability trait negatively predicted the surface learning approach. The second aim of this study was to investigate whether approaches to learning predict academic success, as measured by grade point average. As expected, the surface learning approach negatively predicted achievement. However, contrary to expectations, neither the deep nor the strategic learning approach predicted academic success. This finding may partly be explained by these first-year distance students undergoing a transition to the expectations and requirements of their flexible learning environments. Further research is warranted to establish whether the deep and strategic learning approaches become more likely to predict academic success in the latter years of study, after distance students have adapted to the flexible delivery methods. To this end, a longitudinal study that tracks the academic performance of these students until they complete their degrees or leave the university is recommended