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RISS 인기검색어
- 검색키워드
- 저자 : Piffer (검색결과 4 건)
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Piffer, Davide Korean Society for Bioinformatics 2014 Interdisciplinary Bio Central (IBC) Vol.6 No.4
Sexual dimorphism in intelligence suggests that this phenotype is a sexually selected trait. This view is supported by an overrepresentation (compared to the autosomal genome) of genes affecting cognition on the X chromosome. The aim of this study is to test the hypothesis that sexual selection can explain sex and country-level differences in performance on tests of fluid intelligence. Nationally representative samples from N = 44 countries were obtained from the Programme for International Student Assessment (PISA) Creative Problem Solving (CPS), which evaluates the core of intelligence, that is novel problem solving ability. Sexual selection has the double effect of increasing the prevalence of a favored phenotype and reducing genetic variation in sexually selected traits. Matching these predictions from evolutionary theory, the average country fluid intelligence is positively correlated to sexual dimorphism after partialling out per capita GDP and the latter in turn is inversely correlated to variance in intelligence scores within populations. Males have a higher variance than females but there is a negative correlation between male-female difference in variance and sexual dimorphism in intelligence, suggesting that selection reduces variance more in the selected sex. Average country male height is negatively correlated to sexual dimorphism in intelligence, a fact that supports the notion of a trade-off between physical and intellectual competition in the context of access to females. The results of this study, if replicated, imply that genome-wide association studies of cognition may benefit from a focus on sex chromosomes, which so far have been neglected. Another implication of this study is that intelligence has continued to evolve after different human populations migrated out of Africa and possibly up to the 19th century, as suggested by the substantial variability in sex differences even between neighbouring countries.
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Simple Statistical Tools to Detect Signals of Recent Polygenic Selection
Piffer, Davide Korean Society for Bioinformatics 2014 Interdisciplinary Bio Central (IBC) Vol.6 No.1
A growing body of evidence shows that most psychological traits are polygenic, that is they involve the action of many genes with small effects. However, the study of selection has disproportionately been on one or a few genes and their associated sweep signals (rapid and large changes in frequency). If our goal is to study the evolution of psychological variables, such as intelligence, we need a model that explains the evolution of phenotypes governed by many common genetic variants. This study illustrates simple statistical tools to detect signals of recent polygenic selection: a) ANOVA can be used to reveal significant deviation from random distribution of allele frequencies across racial groups. b) Principal component analysis can be used as a tool for finding a factor that represents the strength of recent selection on a phenotype and the underlying genetic variation. c) Method of correlated vectors: the correlation between genetic frequencies and the average phenotypes of different populations is computed; then, the resulting correlation coefficients are correlated with the corresponding alleles' genome-wide significance. This provides a measure of how selection acted on genes with higher signal to noise ratio. Another related test is that alleles with large frequency differences between populations should have a higher genome-wide significance value than alleles with small frequency differences. This paper fruitfully employs these tools and shows that common genetic variants exhibit subtle frequency shifts and that these shifts predict phenotypic differences across populations.
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Henrique Bosso,Giovanna Emanuella Piffer Soares Arantes,Sandra Maria Barbalho,Elen Landgraf Guiguer,Maricelma da Silva Soares de Souza,Patrıcia Cincotto dos Santos Bueno,Agnaldo Bruno Chies,Priscilla 한국식품영양과학회 2019 Journal of medicinal food Vol.22 No.4
Many studies have shown that plants can be therapeutic alternatives in the prevention or treatment of various diseases. Among these, green coffee may present different pharmacological effects related to the regulation of glycemia and lipid metabolism and is related to the prevention of cardiovascular diseases. The objective of our study was to evaluate the effects of using green and ripe coffee on the metabolic profile and muscular enzymes after the practice of physical exercises in Wistar rats. We included six groups: G1 (control group), G2 (group submitted to swimming), G3 (group that consumed green coffee), G4 (group that consumed green coffee and was submitted to swimming), G5 (group that consumed ripe coffee), and G6 (group that consumed ripe coffee and was submitted to swimming). Our results showed that there was a significant reduction in the percentage of visceral fat in G3, G5, and G6. We did not observe significant modifications in glycemia, lipids, lactate dehydrogenase, ferric reducing ability of plasma, and ferric-xylenol orange. The levels of creatine phosphokinase showed a reduction in the groups G2 and G4. No significant differences were found in the atherogenic indices. There is a global demand for natural compounds that can be safe, cheap, related to minimum side effects, and provide health benefits. Our results show that the use of green or ripe coffee may contribute to reduce the percentage of visceral fat and consequently may protect against further complications once this tissue produces proatherogenic hormones. Furthermore, green coffee may play a role in protecting muscle injury after the practice of physical exercises.
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Gunawardane, K.G. Chandrika,Custance, Deborah M.,Piffer, Davide Korean Society for Bioinformatics 2011 Interdisciplinary Bio Central (IBC) Vol.3 No.4
Previous research has established the existence of individual differences with regards to individuals' optimum time of well-functioning; specifically in terms of being either morning or evening oriented. An association has also emerged between being more evening, as opposed to morning, oriented and having a greater number of sexual partners. The aim of the present study was to investigate whether "eveningness" in males is an evolved sexually dimorphic trait consistent across different cultures. A sample of 179 male Sri Lankan men residing in two different cultural and economic settings, Italy and Sri Lanka, were administered the Morningness-Eveningness Questionnaire (MEQ) followed by assessing their sexual behavior history. The results robustly portrayed a highly significant main effect of MEQ types highlighting the twofold sexual success enjoyed by the evening individuals in both regional locations. Morning oriented individuals, showed a stronger preference for going out and partying than evening-types, suggesting that the higher mating success of evening types is not due to their different lifestyles allowing more opportunities to encounter females. However, evening types exhibited a preference for flirtatious behaviors in the later part of the day. Shoulder-to-hip and handgrip strength, as measures of testosterone levels, were not significantly associated with eveningness. The results are discussed in terms of sexual selection and its interplay with human cultural variation.
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