Biology subjects

Porcelli, D.

Publications and source records attributed to Porcelli, D..

3 recordsLinked to original sources

bioRxiv2021

Experimental sexual selection reveals rapid divergence in male and female reproductive transcriptomes and their interactions

Postcopulatory interactions between the sexes in internally fertilizing species elicits both sexual conflict and sexual selection. Macroevolutionary and comparative studies have linked these processes to rapid transcriptomic evolution in sex-specific tissues and substantial transcriptomic postmating responses in females, patterns of which are altered when mating between reproductively isolated species. Here we test multiple predictions arising from sexual selection and conflict theory about the evolution of sex-specific and tissue-specific gene expression and the postmating response at the microevolutionary level. Following over 150 generations of experimental evolution under either reduced (enforced monogamy) or elevated (polyandry) sexual selection in Drosophila pseudoobscura, we found a substantial effect of sexual selection treatment on transcriptomic divergence in virgin male and female reproductive tissues (testes, male accessory glands, the female reproductive tract and ovaries). Sexual selection treatment also had a dominant effect on the postmating response, particularly in the female reproductive tract - the main arena for sexual conflict - compared to ovaries. This affect was asymmetric with monandry females typically showing more postmating responses than polyandry females, with enriched gene functions varying across treatments. The evolutionary history of the male partner had a larger effect on the postmating response of monandry females, but females from both sexual selection treatments showed unique patterns of gene expression and gene function when mating with males from the alternate treatment. Our microevolutionary results mostly confirm comparative macroevolutionary predictions on the role of sexual selection on transcriptomic divergence and altered gene regulation arising from divergent coevolutionary trajectories between sexual selection treatments.

evolutionary biology↗

bioRxiv2018

Chromatin Accessibility Plays a Key Role in Selective Targeting of Hox Proteins

Hox protein transcription factors specify segmental diversity along the anterior-posterior body axis in metazoans. Understanding the basis of Hox function has long faced the problem that, while the different members of the Hox family show clear functional specificity in vivo, they all show very similar binding specificity in vitro. Based on in vitro studies, cofactors may increase Hox binding selectivity however a satisfactory understanding of in vivo Hox target selectivity is still lacking.\n\nWe have carried out a systematic analysis of the in vivo genomic binding profiles of all eight Drosophila Hox proteins using transient transfection in Kc167 cells to examine Hox protein targeting. We find that Hox proteins show considerable binding selectivity in vivo in the absence of the canonical Hox cofactors Extradenticle and Homothorax. Hox binding selectivity is strongly associated with chromatin accessibility; binding sites in less accessible chromatin show the highest selectivity and the different Hox proteins exhibit different propensities to bind less accessible chromatin. High Hox binding selectivity is also associated with high affinity binding regions, leading to a model where Hox proteins derive binding selectivity through an affinity-based competition with nucleosomes. Provision of the Extradenticle/Homothorax cofactors generally leads to an increase in the number of Hox binding regions and promotes the binding to regions in less accessible chromatin, however the provision of these cofactors has little effect on the overall selectivity of Hox targeting.\n\nThese studies indicate that chromatin accessibility plays a key role in Hox selectivity and we propose that relative chromatin accessibility provides a basis for subtle differences in binding specificity and affinity to generate significantly different sets of genomic targets for different Hox proteins. We suggest that this mechanism may also be relevant to other transcription factor families.

genomics↗

bioRxiv2018

Genomic analysis of European Drosophila melanogaster populations on a dense spatial scale reveals longitudinal population structure and continent-wide selection

Genetic variation is the fuel of evolution, with standing genetic variation especially important for short-term evolution and local adaptation. To date, studies of spatio-temporal patterns of genetic variation in natural populations have been challenging, as comprehensive sampling is logistically difficult, and sequencing of entire populations costly. Here, we address these issues using a collaborative approach, sequencing 48 pooled population samples from 32 locations, and perform the first continent-wide genomic analysis of genetic variation in European Drosophila melanogaster. Our analyses uncover longitudinal population structure, provide evidence for continent-wide selective sweeps, identify candidate genes for local climate adaptation, and document clines in chromosomal inversion and transposable element frequencies. We also characterise variation among populations in the composition of the fly microbiome, and identify five new DNA viruses in our samples.

evolutionary biology↗