Papers by Virginie Orgogozo
Left-right asymmetric genitalia have appeared multiple times independently in insects and have be... more Left-right asymmetric genitalia have appeared multiple times independently in insects and have been associated with changes in mating positions. However, there is little experimental data on how the evolution of genital asymmetries may have affected the evolution of mating positions or vice versa. As opposed to its closely-related species, Drosophila pachea has a conspicuous asymmetry in its male genitalia external lobes, with the left lobe being 1.49 ± 0.08 (SD) times longer and thinner than the right lobe. In a laboratory stock, we found that 20% of the males possess fully symmetric lobes. To better understand how asymmetric genitalia may affect mating, we compared D. pachea copulation behaviour between these mutant males and wild-type males. We found that D. pachea wild-type males adopt a one-sided mating posture with the male always one-sided 8.55° ± 1.79° (SD) towards the female’s right side. Within 45-min recordings, all wild-type males did mate whereas 39% of symmetric mutants failed to form a stable mating complex and did not mate. In successful copulations, symmetric mutants also adopted a right-sided mating posture but the angle between male and female bodies was significantly more variable compared to wild-type males. Our results suggest that lobe size asymmetry is required for the formation of a stable mating complex and for the positioning of the male according to a precise angle on the female. However, lobe size asymmetry is not required for D. pachea right-sided mating posture
The folder contains movies of /Drosophila pachea/ copulations, image exports from those movies an... more The folder contains movies of /Drosophila pachea/ copulations, image exports from those movies and scanning electron microscopy images of /D. pachea/ copulation complexes. In addition, we provide three data files, with the measurements that were used to describe mating behavior, mating positions and SEM copulation complexes. The md5sum of Rhebergen_BMC_2016.tar.gz is: d0daef793b2bce7863a482f11bee92b
Fly, Jan 28, 2016
Sample homogenization is an essential step for genomic DNA extraction, with multiple downstream a... more Sample homogenization is an essential step for genomic DNA extraction, with multiple downstream applications in Molecular Biology. Genotyping hundreds or thousands of samples requires an automation of this homogenization step, and high throughput homogenizer equipment currently costs 7000 euros or more. We present an apparatus for homogenization of individual Drosophila adult flies in 96-well micro-titer dishes, which was built from a small portable paint-shaker (F5 portable paint-shaker, Ushake). Single flies are disrupted in each well that contains extraction buffer and a 4-mm metal ball. Our apparatus can hold up to five 96-well micro-titer plates. Construction of the homogenizer apparatus takes about 3-4 days, and all equipment has been obtained from a home improvement store. The total material cost is approximately 700 euros including the paint-shaker. We tested the performance of our apparatus using the ZR-96 Quick-gDNA™ kit (Zymo Research) homogenization buffer and achieved n...
Methods in molecular biology (Clifton, N.J.), 2011
Degenerate primers are mixtures of similar oligonucleotides that are used in a PCR, so-called deg... more Degenerate primers are mixtures of similar oligonucleotides that are used in a PCR, so-called degenerate PCR, to amplify unknown DNA sequences, typically coding sequences of genes. Degenerate primers are designed based on sequence data of related and already sequenced gene homologs. This method is useful for identifying new members of a gene family or orthologous genes from different organisms where genomic information is not available. We describe here how to design degenerate primers, set up the PCR (with genomic DNA or cDNA as a template), clone the resulting PCR fragments, and sequence them. Since this method only yields partial coding sequences, complete gene sequences must then be achieved by other approaches such as inverse PCR (see Chapter 16), 5' RACE, 3' RACE, or circular RACE (see Chapter 15).
Science, 2012
Limiting Your Options Many species are dependent on specific resources that may limit their range... more Limiting Your Options Many species are dependent on specific resources that may limit their range of hosts to that of a few or even a single species. The restriction of the fly Drosophila pachea to senita cactus is a classic case of an ecological specialization. Lang et al. (p. 1658 ) reveal how multiple amino acid substitutions in the neverland gene have rendered D. pachea dependent upon the lathosterol of the senita cactus. Thus, relatively few genetic changes can play a large role in determining a species' ecological niche.
PLoS ONE, 2013
In contrast to male genitalia that typically exhibit patterns of rapid and divergent evolution am... more In contrast to male genitalia that typically exhibit patterns of rapid and divergent evolution among internally fertilizing animals, female genitalia have been less well studied and are generally thought to evolve slowly among closely-related species. As a result, few cases of male-female genital coevolution have been documented. In Drosophila, female copulatory structures have been claimed to be mostly invariant compared to male structures. Here, we re-examined male and female genitalia in the nine species of the D. melanogaster subgroup. We describe several new species-specific female genital structures that appear to coevolve with male genital structures, and provide evidence that the coevolving structures contact each other during copulation. Several female structures might be defensive shields against apparently harmful male structures, such as cercal teeth, phallic hooks and spines. Evidence for male-female morphological coevolution in Drosophila has previously been shown at the post-copulatory level (e.g., sperm length and sperm storage organ size), and our results provide support for male-female coevolution at the copulatory level.
Frontiers in Genetics, 2015
An integrative view of diversity and singularity in the living world requires a better understand... more An integrative view of diversity and singularity in the living world requires a better understanding of the intricate link between genotypes and phenotypes. Here we reemphasize the old standpoint that the genotype-phenotype (GP) relationship is best viewed as a connection between two differences, one at the genetic level and one at the phenotypic level. As of today, predominant thinking in biology research is that multiple genes interact with multiple environmental variables (such as abiotic factors, culture, or symbionts) to produce the phenotype. Often, the problem of linking genotypes and phenotypes is framed in terms of genotype and phenotype maps, and such graphical representations implicitly bring us away from the differential view of GP relationships. Here we show that the differential view of GP relationships is a useful explanatory framework in the context of pervasive pleiotropy, epistasis, and environmental effects. In such cases, it is relevant to view GP relationships as differences embedded into differences. Thinking in terms of differences clarifies the comparison between environmental and genetic effects on phenotypes and helps to further understand the connection between genotypes and phenotypes.
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Papers by Virginie Orgogozo