Evolution of sexual dimorphism of wing shape in the Drosophila melanogaster subgroup

Background: Sexual dimorphism of body size has been the subject of numerous studies, but few have examined sexual shape dimorphism (SShD) and its evolution. Allometry, the shape change associated with size variation, has been suggested to be a main component of SShD. Yet little is known about the relative importance of the allometric and non-allometric components for the evolution of SShD. Results: We investigated sexual dimorphism in wing shape in the nine species of the Drosophila melanogaster subgroup. We used geometric morphometrics to characterise wing shape and found significant SShD in all nine species. The amount of shape difference and the diversity of the shape changes evolved across the group. However, mapping the divergence of SShD onto the phylogeny of the Drosophila melanogaster subgroup indicated that there is little phylogenetic signal. Finally, allometry accounted for a substantial part of SShD, but did not explain the bulk of evolutionary divergence in SShD because allometry itself was found to be evolutionarily plastic. Conclusion: SShD in the Drosophila wing can evolve rapidly and therefore shows only weak phylogenetic structure. The variable contribution of allometric and non-allometric components to the evolutionary divergence of SShD and the evolutionary plasticity of allometry suggest that SShD and allometry are influenced by a complex interaction of processes

Developmental Stability: A Major Role for Cyclin G in Drosophila melanogaster

Morphological consistency in metazoans is remarkable given the pervasive occurrence of genetic variation, environmental effects, and developmental noise. Developmental stability, the ability to reduce developmental noise, is a fundamental property of multicellular organisms, yet its genetic bases remains elusive. Imperfect bilateral symmetry, or fluctuating asymmetry, is commonly used to estimate developmental stability. We observed that Drosophila melanogaster overexpressing Cyclin G (CycG) exhibit wing asymmetry clearly detectable by sight. Quantification of wing size and shape using geometric morphometrics reveals that this asymmetry is a genuine—but extreme—fluctuating asymmetry. Overexpression of CycG indeed leads to a 40-fold increase of wing fluctuating asymmetry, which is an unprecedented effect, for any organ and in any animal model, either in wild populations or mutants. This asymmetry effect is not restricted to wings, since femur length is affected as well. Inactivating CycG by RNAi also induces fluctuating asymmetry but to a lesser extent. Investigating the cellular bases of the phenotypic effects of CycG deregulation, we found that misregulation of cell size is predominant in asymmetric flies. In particular, the tight negative correlation between cell size and cell number observed in wild-type flies is impaired when CycG is upregulated. Our results highlight the role of CycG in the control of developmental stability in D. melanogaster. Furthermore, they show that wing developmental stability is normally ensured via compensatory processes between cell growth and cell proliferation. We discuss the possible role of CycG as a hub in a genetic network that controls developmental stability

Fontes et historia. Prace dedykowane Antoniemu Gąsiorowskiemu. Red. Tomasz Jurek, Izabela Skierska, 2007

Recenzja: Fontes et historia. Prace dedykowane Antoniemu Gąsiorowskiemu [red. Tomasz Jurek, Izabela Skierska], Instytut Historii Polskiej Akademii Nauk, Poznań 2007, ss. 284

Data from: Testing and quantifying phylogenetic signals and homoplasy in morphometric data

The relationship between morphometrics and phylogenetic analysis has long been controversial. Here we propose an approach that is based on mapping morphometric traits onto phylogenies derived from other data and thus avoids the pitfalls encountered by previous studies. This method treats shape as a single, multidimensional character. We propose a test for the presence of a phylogenetic signal in morphometric data, which simulates the null hypothesis of the complete absence of phylogenetic structure by permutation of the shape data among the terminal taxa. We also propose 2 measures of the fit of morphometric data to the phylogeny that are direct extensions of the consistency index and retention index used in traditional cladistics. We apply these methods to a small study of the evolution of wing shape in the Drosophila melanogaster subgroup, for which a very strongly supported phylogeny is available. This case study reveals a significant phylogenetic signal and a relatively low degree of homoplasy. Despite the low homoplasy, the shortest tree computed from landmark data on wing shape is inconsistent with the well-supported phylogenetic tree from molecular data, underscoring that morphometric data may not provide reliable information for inferring phylogeny

Data from: Testing and quantifying phylogenetic signals and homoplasy in morphometric data

The relationship between morphometrics and phylogenetic analysis has long been controversial. Here we propose an approach that is based on mapping morphometric traits onto phylogenies derived from other data and thus avoids the pitfalls encountered by previous studies. This method treats shape as a single, multidimensional character. We propose a test for the presence of a phylogenetic signal in morphometric data, which simulates the null hypothesis of the complete absence of phylogenetic structure by permutation of the shape data among the terminal taxa. We also propose 2 measures of the fit of morphometric data to the phylogeny that are direct extensions of the consistency index and retention index used in traditional cladistics. We apply these methods to a small study of the evolution of wing shape in the Drosophila melanogaster subgroup, for which a very strongly supported phylogeny is available. This case study reveals a significant phylogenetic signal and a relatively low degree of homoplasy. Despite the low homoplasy, the shortest tree computed from landmark data on wing shape is inconsistent with the well-supported phylogenetic tree from molecular data, underscoring that morphometric data may not provide reliable information for inferring phylogeny

Testing and quantifying phylogenetic signals and homoplasy in morphometric data

Abstract.—The relationship between morphometrics and phylogenetic analysis has long been controversial. Here we pro-pose an approach that is based on mapping morphometric traits onto phylogenies derived from other data and thus avoids the pitfalls encountered by previous studies. This method treats shape as a single, multidimensional character. We propose a test for the presence of a phylogenetic signal in morphometric data, which simulates the null hypothesis of the complete absence of phylogenetic structure by permutation of the shape data among the terminal taxa. We also propose 2 measures of the fit of morphometric data to the phylogeny that are direct extensions of the consistency index and retention index used in traditional cladistics. We apply these methods to a small study of the evolution of wing shape in the Drosophila melanogaster subgroup, for which a very strongly supported phylogeny is available. This case study reveals a significant phylogenetic signal and a relatively low degree of homoplasy. Despite the low homoplasy, the shortest tree computed from landmark data on wing shape is inconsistent with the well-supported phylogenetic tree from molecular data, underscoring that mor-phometric data may not provide reliable information for inferring phylogeny. [Drosophilidae; geometric morphometrics; homoplasy; phylogeny; Procrustes superposition; shape; squared-change parsimony.] Understanding the evolution of organismal form i

Phylogeny of Drosophila melanogaster subgroup

The phylogeny of the 9 species in the study, as a Nexus fil

Long-term evolution of quantitative traits in the Drosophila melanogaster species subgroup

International audienc

Comparison of the effect of caseload midwifery program and standard midwifery-led care on primiparous birth outcomes : a retrospective cohort matching study

Background: The effectiveness of continuity of care during the perinatal period is well documented, but implementing continuity of care model to practice requires evaluation. Aim: To evaluate the effect of a caseload midwifery program (CMP) on birth outcomes and rates of perinatal interventions at a metropolitan tertiary hospital in Australia, compared with standard midwifery-led care (SMC). Methods: This was a retrospective, matched-cohort study. We extracted the data of 1000 nulliparous women from records of 19,001 women who gave birth at the hospital from 2011 to 2014. We used basic statistical tests to compare baseline demographic data, and logistic regression to calculate odds ratios, to evaluate maternal and neonatal outcomes. Results: Adjusted regression analysis for the primary outcome showed that compared with women who received SMC, women who received care through CMP had an increased rate of normal vaginal birth (69% vs. 50%, OR = 1.79, 95%, CI = 1.38–2.32). Assessment of secondary outcomes showed that the women in CMP group had decreased rates of instrumental birth (15% vs. 26%, OR = 0.48, 95% CI = 0.35–0.66), episiotomy (23% vs. 40%, OR = 0.43, 95% CI = 0.33–0.57), epidural analgesia (33% vs. 43%, OR = 0.64, 95% CI = 0.50–0.83) and amniotomy (35% vs. 50%, OR = 0.56, 95% CI = 0.43–0.72). The CMP group also had greater rates of water immersion (54% vs. 22%, OR = 4.18, 95% CI = 3.17–5.5), physiological 3rd stage (7% vs. 1%, OR = 11.71, 95% CI = 3.56–38.43) and 2nd degree tear (34% vs. 24%, OR = 1.60, 95% CI = 1.21–2.11). There were no significant differences between the two groups for rates of other secondary outcomes including Caesarean section, cervical ripening procedures, third- and fourth-degree tears, postpartum haemorrhage and neonatal outcomes. Conclusion: CMP care is associated with increased rate of normal vaginal birth which supports wider implementation of the model. In addition, using routinely collected data and a cohort matching design can be an effective approach to evaluate maternal and neonatal outcomes