User's guide to correlation coefficients

Akoğlu, Haldun

doi:10.1016/j.tjem.2018.08.001

Cited by 3,694 publications

(2,374 citation statements)

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“…In X/Y sex determination systems, it has been posited that mechanisms should exist to ensure that the expression levels of genes on the X-chromosome (X) and autosomes (A) would be approximately equivalent in both males (with hemizygous X) and females (homozygous X), such that the ratio of expression of X/A in each sex should equal one [38, 58]. In turn, it may be expected that X male /X female = A male /A female = 1 [38].…”

Section: Resultsmentioning

confidence: 99%

Absence of a faster-X effect in beetles (Tribolium, Coleoptera)

Whittle

Kulkarni

Extavour

2019

Preprint

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1Background. The faster-X effect, namely the rapid evolution of protein-coding genes on the X-chromosome, 2 has been reported in numerous metazoans. However, the prevalence of this phenomenon across metazoans and 3 its potential causes remain largely unresolved. Analysis of sex-biased genes may elucidate its possible 4 mechanisms: a more pronounced faster-X effect in male-biased genes than in female-biased or unbiased genes, 5 suggests fixation of recessive beneficial mutations rather than genetic drift. Further, theory predicts that the 6 faster-X effect should be promoted by X-chromosome dosage compensation, but this topic remains rarely 7 empirically examined. 8 9Results. Here, we asked whether we could detect a faster-X effect in genes of the beetle Tribolium castaneum 10 (and T. freemani orthologs), which has X/Y sex-determination and heterogametic males. Our comparison of 11 protein sequence divergence (dN/dS) on the X-chromosome versus autosomes indicated the complete absence 12 of a faster-X effect. Further, analyses of sex-biased gene expression revealed that the X-chromosome was 13 strongly enriched for ovary-biased genes, which evolved under exceptionally high constraint. An evaluation of 14 male X-chromosome dosage compensation in the gonads and in non-gonadal somatic tissues showed an 15 extreme lack of compensation in the testis. This under-expression of the X chromosome in males may limit the 16 phenotypic effect, and therefore likelihood of fixation, of recessive beneficial X-linked mutations in genes 17 transcribed in male gonads. 19Conclusions. We show that these beetles display a rare unequivocal example of the absence of a faster-X effect 20 in a metazoan. We propose two potential causes for this, namely high constraint on X-linked ovary-biased 21 genes, and an extreme lack of dosage compensation of genes transcribed in the testis. 23Keywords: Tribolium castaneum, faster-X, sex-biased expression, dosage compensation, dN/dS 24 25 53 chromosome and autosomes, revealed a faster-X effect for all three classes of sex biased genes 54 (male-biased, female-based and unbiased). In this study, protein sequence divergence was 55 highest in male-biased genes and lowest in female-biased genes, empirically supporting a model 56 4 of fixation of beneficial mutations on the X chromosome [15, 16]. In chickens, which have WZ 57 sex chromosomes and female heterogamy, elevated dN/dS has been reported across all studied 58 genes on the Z-chromosome, consistent with the faster-X (or faster-Z in this case) effect [21]. 59 However, the prediction of higher dN/dS for female-biased genes on the Z-chromosome was not 60 met in this study, suggesting that the faster-Z in these birds was not due to fixation of recessive 61 beneficial mutations, and rather might be attributable to fixation of neutral or slightly deleterious 62 mutations via genetic drift [7, 16]. Recently, similar results were reported for the W/Z 63 chromosomes of Heliconius butterflies [14]. At present however, the study of the faster-X effect, 64 i...

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Section: Resultsmentioning

confidence: 99%

Absence of a faster-X effect in beetles (Tribolium, Coleoptera)

Whittle

Kulkarni

Extavour

2019

Preprint

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“…For the same reason, the Spearman correlation was used to investigate the association of motor scales scores with the BC. We considered a correlation to be weak, moderate, or strong when the coefficient was below 0.3, near 0.5, or approaching +1.0, respectively . P < .05 was considered statistically significant.…”

Section: Methodsmentioning

confidence: 99%

Evaluation of body composition as a potential biomarker in spinal muscular atrophy

et al. 2020

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Introduction We aimed to investigate the correlation between body composition (BC) and spinal muscular atrophy (SMA)‐specific motor function assessments. Methods Patients with SMA types I or II, aged 1 to 10 years, were recruited in this cross‐sectional study. The protocol included anthropometric measurements, and dual‐energy X‐ray absoprtiometry to assess fat mass (FM), lean mass (LM), fat‐free mass (FFM), FM and FFM indexes (FMI, FFMI), and motor function assessments (Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders scale for SMAI, and Hammersmith Functional Motor Scale―Expanded for SMAII). Results Eighty‐eight children were included. All had a higher FM percentage than reference values. Motor function was moderately correlated with body mass index (BMI), FFMI, and LMI in SMAI, and weakly correlated with FFMI, LMI, and LM:FM ratio in SMAII. Discussion BC shows promise as a potential biomarker for SMA, but further studies are needed.

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“…To address whether Wiki and Wiki‐based learning analytics facilitated collaborative learning on the group level, the correlations between the various statistics of group‐level Wiki behavioral data and the group unfairness index were first explored. Results (Table 2) show that the group‐level revision count and unfairness index had a moderate negative correlation (|r| > 0.3, [Akoglu, ]). This shows that fairness of group work distribution had a positive relationship with active participation of group members in making revisions on the analytics‐supported Wiki.…”

Section: Resultsmentioning

confidence: 99%

“…Correlations between students' group‐level statistics of Wiki behaviors and the average scores of group members in the inquiry project were analyzed. As Table 3 shows, there was a moderate correlation (|r| > 0.3, [Akoglu, ]) between the percentage of sentences with higher‐order thinking and the performance score. With reference to the thinking orders in secondary school students' writing [Hu, ; Krathwohl, ], this result implies that more creation and evaluation in collaborative writing would lead to a higher performance score.…”

Section: Resultsmentioning

confidence: 99%

“…To address whether Wiki and Wiki-based learning analytics facilitated collaborative learning on the group level, the correlations between the various statistics of group-level Wiki behavioral data and the group unfairness index were first explored. Results (Table 2) show that the group-level revision count and unfairness index had a moderate negative correlation (|r| > 0.3, [Akoglu, 2018] Students' performance scores in the inquiry project serve as another indicator of the outcome of their collaborative learning. Correlations between students' group-level statistics of Wiki behaviors and the average scores of group members in the inquiry project were analyzed.…”

Section: Results and Discussion Rq1: Effectiveness In The Group Levelmentioning

confidence: 99%

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Relations among participation, fairness and performance in collaborative learning with Wiki‐based analytics

Luo

et al. 2019

Proceedings of the Association for Information Science and Tech

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Utilizing data analytics for supporting collaborative learning is under‐studied in secondary education. This study aims to evaluate the effectiveness of Wiki and Wiki‐based learning analytics in facilitating collaborative learning in a junior secondary school, in terms of students' participation, contribution, performance, and perception. A Wiki‐based learning analytic tool, Wikiglass, was employed for visualizing statistics of students' contributions and participation (e.g., revision counts) in Wiki, on both the group and individual levels. System log, student survey and performance data were collected from students involved in a Wiki‐supported inquiry project assignment. An Unfairness Index is proposed to measure students' group work distribution. Results of statistical analyses show that fairness of group work distribution was positively related to active participation in revisions on Wiki on the group level, and the number of sentences with higher‐order thinking was related to group performance scores. On the level of individual students, Wiki‐based analytics increased the visibility of work distribution and peers' work progress and contributions which might have changed students' collaborative behaviors.

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User's guide to correlation coefficients

Cited by 3,694 publications

References 1 publication

Absence of a faster-X effect in beetles (Tribolium, Coleoptera)

Absence of a faster-X effect in beetles (Tribolium, Coleoptera)

Evaluation of body composition as a potential biomarker in spinal muscular atrophy

Relations among participation, fairness and performance in collaborative learning with Wiki‐based analytics

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