| 1. |
- Ferretti, Ana B. S. M., et al.
(författare)
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High dynamism for neo-sex chromosomes : satellite DNAs reveal complex evolution in a grasshopper
- 2020
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Ingår i: Heredity. - : NATURE PUBLISHING GROUP. - 0018-067X .- 1365-2540. ; 125:3, s. 124-137
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Tidskriftsartikel (refereegranskat)abstract
- A common characteristic of sex chromosomes is the accumulation of repetitive DNA, which accounts for their diversification and degeneration. In grasshoppers, the X0 sex-determining system in males is considered ancestral. However, in some species, derived variants like neo-XY in males evolved several times independently by Robertsonian translocation. This is the case ofRonderosia bergii, in which further large pericentromeric inversion in the neo-Y also took place, making this species particularly interesting for investigating sex chromosome evolution. Here, we characterized the satellite DNAs (satDNAs) and transposable elements (TEs) of the species to investigate the quantitative differences in repeat composition between male and female genomes putatively associated with sex chromosomes. We found a total of 53 satDNA families and 56 families of TEs. The satDNAs were 13.5% more abundant in males than in females, while TEs were just 1.02% more abundant in females. These results imply differential amplification of satDNAs on neo-Y chromosome and a minor role of TEs in sex chromosome differentiation. We showed highly differentiated neo-XY sex chromosomes owing to major amplification of satDNAs in neo-Y. Furthermore, chromosomal mapping of satDNAs suggests high turnover of neo-sex chromosomes inR. bergiiat the intrapopulation level, caused by multiple paracentric inversions, amplifications, and transpositions. Finally, the species is an example of the action of repetitive DNAs in the generation of variability for sex chromosomes after the suppression of recombination, and helps understand sex chromosome evolution at the intrapopulation level.
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| 2. |
- Ferretti, Ana B. S. M., et al.
(författare)
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How dynamic could be the 45S rDNA cistron? : An intriguing variability in a grasshopper species revealed by integration of chromosomal and genomic data
- 2019
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Ingår i: Chromosoma. - : SPRINGER. - 0009-5915 .- 1432-0886. ; 128:2, s. 165-175
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Tidskriftsartikel (refereegranskat)abstract
- To better understand the structure and variability of the 45S rDNA cistron and its evolutionary dynamics in grasshoppers, we performed a detailed analysis combining classical and molecular cytogenetic data with whole-genome sequencing in Abracris flavolienata, which shows extraordinary variability in the chromosomal distribution for this element. We found astonishing variability in the number and size of rDNA clusters at intra- and inter-population levels. Interestingly, FISH using distinct parts of 45S rDNA cistron (18S rDNA, 28S rDNA, and ITS1) as probes revealed a distinct number of clusters, suggesting independent mobility and amplification of the 45S rDNA components. This hypothesis is consistent with the higher genomic coverage of almost the entire cistron of 45S rDNA observed in A. flavolineata compared to other grasshoppers, besides coverage variability along the 45S rDNA cistron in the species. In addition, these differences in coverage for distinct components of the 45S rDNA cistron indicate emergence of pseudogenes evidenced by existence of truncated sequences, demonstrating the rDNA dynamics in the species. Although the chromosomal distribution of 18S rDNA was highly variable, the chromosomes 1, 3, 6, and 9 harbored rDNA clusters in all individuals with the occurrence of NOR activity in pair 9, suggesting ancestry or selective pressures to prevent pseudogenization of rDNA sequences in this chromosome pair. Additionally, small NORs and cryptic rDNA loci were observed. Finally, there was no evidence of enrichment and association of transposable elements, at least, inside or nearby rDNA cistron. These findings broaden our knowledge of rDNA dynamics, revealing an independent movement and amplification of segments of 45S rDNA cistron, which in A. flavolineata could be attributed to ectopic recombination.
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| 3. |
- Martí, Emiliano, et al.
(författare)
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Cytogenomic analysis unveils mixed molecular evolution and recurrent chromosomal rearrangements shaping the multigene families on Schistocerca grasshopper genomes
- 2021
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Ingår i: Evolution. - : John Wiley & Sons. - 0014-3820 .- 1558-5646. ; 75:8, s. 2027-2041
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Tidskriftsartikel (refereegranskat)abstract
- Multigene families are essential components of eukaryotic genomes and play key roles either structurally and functionally. Their modes of evolution remain elusive even in the era of genomics, because multiple multigene family sequences coexist in genomes, particularly in large repetitive genomes. Here, we investigate how the multigene families 18S rDNA, U2 snDNA, and H3 histone evolved in 10 species of Schistocerca grasshoppers with very large and repeat-enriched genomes. Using sequenced genomes and fluorescence in situ hybridization mapping, we find substantial differences between species, including the number of chromosomal clusters, changes in sequence abundance and nucleotide composition, pseudogenization, and association with transposable elements (TEs). The intragenomic analysis of Schistocerca gregaria using long-read sequencing and genome assembly unveils conservation for H3 histone and recurrent pseudogenization for 18S rDNA and U2 snDNA, likely promoted by association with TEs and sequence truncation. Remarkably, TEs were frequently associated with truncated copies, were also among the most abundant in the genome, and revealed signatures of recent activity. Our findings suggest a combined effect of concerted and birth-and-death models driving the evolution of multigene families in Schistocerca over the last 8 million years, and the occurrence of intra- and interchromosomal rearrangements shaping their chromosomal distribution. Despite the conserved karyotype in Schistocerca, our analysis highlights the extensive reorganization of repetitive DNAs in Schistocerca, contributing to the advance of comparative genomics for this important grasshopper genus.
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| 4. |
- Milani, Diogo, et al.
(författare)
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Out of patterns, the euchromatic B chromosome of the grasshopper Abracris flavolineata is not enriched in high-copy repeats
- 2021
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Ingår i: Heredity. - : Springer Nature. - 0018-067X .- 1365-2540. ; 127:5, s. 475-483
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Tidskriftsartikel (refereegranskat)abstract
- In addition to the normal set of standard (A) chromosomes, some eukaryote species harbor supernumerary (B) chromosomes. In most cases, B chromosomes show differential condensation with respect to A chromosomes and display dark C-bands of heterochromatin, and some of them are highly enriched in repetitive DNA. Here we perform a comprehensive NGS (next-generation sequencing) analysis of the repeatome in the grasshopper Abracris flavolineata aimed at uncovering the molecular composition and origin of its B chromosome. Our results have revealed that this B chromosome shows a DNA repeat content highly similar to the DNA repeat content observed for euchromatic (non-C-banded) regions of A chromosomes. Moreover, this B chromosome shows little enrichment for high-copy repeats, with only a few elements showing overabundance in B-carrying individuals compared to the 0B individuals. Consequently, the few satellite DNAs (satDNAs) mapping on the B chromosome were mostly restricted to its centromeric and telomeric regions, and they displayed much smaller bands than those observed on the A chromosomes. Our data support the intraspecific origin of the B chromosome from the longest autosome by misdivision, isochromosome formation, and additional restructuring, with accumulation of specific repeats in one or both B chromosome arms, yielding a submetacentric B. Finally, the absence of B-specific satDNAs, which are frequent in other species, along with its euchromatic nature, suggest that this B chromosome arose recently and might still be starting a heterochromatinization process. On this basis, it could be a good model to investigate the initial steps of B chromosome evolution.
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| 5. |
- Milani, Diogo, et al.
(författare)
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Satellite DNAs Unveil Clues about the Ancestry and Composition of B Chromosomes in Three Grasshopper Species
- 2018
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Ingår i: Genes. - : MDPI AG. - 2073-4425. ; 9:11
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Tidskriftsartikel (refereegranskat)abstract
- Supernumerary (B) chromosomes are dispensable genomic elements occurring frequently among grasshoppers. Most B chromosomes are enriched with repetitive DNAs, including satellite DNAs (satDNAs) that could be implicated in their evolution. Although studied in some species, the specific ancestry of B chromosomes is difficult to ascertain and it was determined in only a few examples. Here we used bioinformatics and cytogenetics to characterize the composition and putative ancestry of B chromosomes in three grasshopper species, Rhammatocerus brasiliensis, Schistocerca rubiginosa, and Xyleus discoideus angulatus. Using the RepeatExplorer pipeline we searched for the most abundant satDNAs in Illumina sequenced reads, and then we generated probes used in fluorescent in situ hybridization (FISH) to determine chromosomal position. We used this information to infer ancestry and the events that likely occurred at the origin of B chromosomes. We found twelve, nine, and eighteen satDNA families in the genomes of R. brasiliensis, S. rubiginosa, and X. d. angulatus, respectively. Some satDNAs revealed clustered organization on A and B chromosomes varying in number of sites and position along chromosomes. We did not find specific satDNA occurring in the B chromosome. The satDNAs shared among A and B chromosomes support the idea of putative intraspecific ancestry from small autosomes in the three species, i.e., pair S11 in R. brasiliensis, pair S9 in S. rubiginosa, and pair S10 in X. d. angulatus. The possibility of involvement of other chromosomal pairs in B chromosome origin is also hypothesized. Finally, we discussed particular aspects in composition, origin, and evolution of the B chromosome for each species.
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| 6. |
- Palacios-Gimenez, Octavio M., et al.
(författare)
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Eight Million Years of Satellite DNA Evolution in Grasshoppers of the Genus Schistocerca Illuminate the Ins and Outs of the Library Hypothesis
- 2020
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Ingår i: Genome Biology and Evolution. - : Oxford University Press (OUP). - 1759-6653. ; 12:3, s. 88-102
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Tidskriftsartikel (refereegranskat)abstract
- Satellite DNA (satDNA) is an abundant class of tandemly repeated noncoding sequences, showing high rate of change in sequence, abundance, and physical location. However, the mechanisms promoting these changes are still controversial. The library model was put forward to explain the conservation of some satDNAs for long periods, predicting that related species share a common collection of satDNAs, which mostly experience quantitative changes. Here, we tested the library model by analyzing three satDNAs in ten species of Schistocerca grasshoppers. This group represents a valuable material because it diversified during the last 7.9 Myr across the American continent from the African desert locust (Schistocerca gregaria), and this thus illuminates the direction of evolutionary changes. By combining bioinformatic and cytogenetic, we tested whether these three satDNA families found in S. gregaria are also present in nine American species, and whether differential gains and/or losses have occurred in the lineages. We found that the three satDNAs are present in all species but display remarkable interspecies differences in their abundance and sequences while being highly consistent with genus phylogeny. The number of chromosomal loci where satDNA is present was also consistent with phylogeny for two satDNA families but not for the other. Our results suggest eminently chance events for satDNA evolution. Several evolutionary trends clearly imply either massive amplifications or contractions, thus closely fitting the library model prediction that changes are mostly quantitative. Finally, we found that satDNA amplifications or contractions may influence the evolution of monomer consensus sequences and by chance playing a major role in driftlike dynamics.
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| 7. |
- Afzali Gorouh, Hossein, et al.
(författare)
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Thermal modelling and experimental evaluation of a novel concentrating photovoltaic thermal collector (CPVT) with parabolic concentrator
- 2022
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Ingår i: Renewable energy. - : Elsevier. - 0960-1481 .- 1879-0682. ; 181, s. 535-553
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Tidskriftsartikel (refereegranskat)abstract
- In the present study, a zero-dimensional thermal model has been developed to analyze a novel low concentration photovoltaic-thermal (CPVT) collector. The model has been developed by driving heat transfer and energy balance equations for each part of the collector and then solving all the equations simultaneously. Moreover, a Monte-Carlo ray-tracing software has been used for optical stimulations of the parabolic trough solar collector. The novel CPVT collector has been experimentally tested at Gävle University (Sweden) and the model has been validated against the experimental results. The primary energy saving equivalent to the thermal-electrical power cogeneration of the CPVT collector has been determined. The effect of glass cover removal, heat transfer fluid (HTF) inlet temperature and mass flow rate on the collector performance has been investigated. The optimum HTF mass flow rates of the collector for maximum electrical yield and overall primary energy saving were determined under specified operating conditions by considering the pump consumption. The effect of mean fluid temperature on the thermal and electrical efficiencies has been studied and the characteristic equation of the thermal efficiency has been obtained. The thermal and electrical peak efficiencies of the collector have been found to be 69.6% and 6.1%, respectively.
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| 8. |
- Cabral, Diogo, PhD, 1990-
(författare)
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Development and performance comparison of a modified glazed CPC hybrid solar collector coupled with a bifacial PVT receiver
- 2022
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Ingår i: Applied Energy. - : Elsevier. - 0306-2619 .- 1872-9118. ; 325
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Tidskriftsartikel (refereegranskat)abstract
- Innovative concentrating PVT solar collector concepts based on a CPC geometry concept were developed to outperform the asymmetric Solarus CPVT collector and therefore decrease the energy/performance gap between CPVT and PV/ST solar collectors. The updated reflector geometry proved to be the most suitable reflector geometry for CPVTs, where the electrical peak efficiency per gross area reached 10.6%, which is +16.5%rel higher than the electrical peak efficiency of the Solarus CPVT. Optical efficiencies of η0 = 62.3% and η0 = 61.8% for CPC 1 and CPC 2 have been achieved, respectively. A PV module (0.5 m2) combined with an ST solar collector (0.5 m2) system to be able to deliver the same overall energy yield as the newly developed CPVT collector (1 m2) requires on average +0.02 m2 (at 45 °C), −0.06 m2 (at 55 °C) and −0.15 m2 (at 65 °C) of installed area, for a wide range of latitudes. A CPC-PVT system to increase its competitiveness requires a material cost reduction and at the same time an increased overall efficiency. Nevertheless, the energy/performance gap between a system composed of PV + ST technologies and a CPC-PVT decreased significantly.
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| 9. |
- Cabral, Diogo, PhD, 1990-
(författare)
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Development of a glazed CPC-PVT solar collector coupled with a bifacial PVT receiver
- 2021
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Two innovative concentrating PVT solar collector geometry concepts based on a CPC geometry concept were built and tested, and subsequently, a comparative analysis against the Solarus PowerCollector has been developed.The results revealed that the updated version of the CPC geometry is the most suitable for CPVTs, where the electrical peak efficiency per gross area reached 10.6 % for both design concepts, which are +16.5 %rel higher than the Solarus PowerCollector. Furthermore, the heat loss coefficients were registered, with U1 = 5.0 W/m2.K (η0 = 62.3 %) and U1 = 5.4 W/m2.K (η0 = 61.8 %) for CPC 1 and CPC 2, respectively. Additionally, the overall efficiency of both design concepts achieved a higher overall efficiency (by +1.1 %rel) than the Solarus PowerCollector.A PV module (0.5 m2) combined with an ST collector (0.5 m2) system to be able to deliver the same overall energy yield as the newly developed PVT collector (1 m2) requires on average +0.02 m2 (at 45 ºC), -0.06 m2 (at 55 ºC) and -0.15 m2 (at 65 ºC) of installed area, for a wide range of latitudes.Notwithstanding the improved IAM and overall efficiencies of the CPC 1 solar collector, a CPC-PVT system to increase its competitiveness requires a material cost reduction and at the same time an increased thermal efficiency (by adding a selective surface to the dead-areas (i.e. non-producing areas) or a low-emissivity coating to the receiver core). Nevertheless, the energy/performance gap between a system composed of PV+ST technologies and a CPC-PVT decreased.
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| 10. |
- Cabral, Diogo, et al.
(författare)
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Electrical and thermal performance evaluation of a district heating system composed of asymmetric low concentration PVT solar collector prototypes
- 2018
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Ingår i: PROCEEDINGS OF THE ISES EUROSUN 2018 CONFERENCE - 12TH INTERNATIONAL CONFERENCE ON SOLAR ENERGY FOR BUILDINGS AND INDUSTRY. - Freiburg, Germany : INTL SOLAR ENERGY SOC. ; , s. 755-763
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Konferensbidrag (refereegranskat)abstract
- Photovoltaic-Thermal (PVT) solar collectors generate electricity and heat from the same gross area. The annual electrical and thermal yields of these systems are dependent on the PVT collector technology, as well as the climate and the type of solar thermal system implemented. This review presents an evaluation of a district heating system composed of 20 asymmetric hybrid low concentrator PVT (C-PVT) solar collector prototypes. The system is installed in a South wall facade in order to maximise the available space (with a tilt of 20 degrees and an orientation of 5 degrees W). The thermal system is connected to the district heating network, thus heating the University buildings. On the other hand, the electrical system is grid-connected, where it feeds the grid directly. Real measurement data has been collected and compared with a thermal (through ScenoCalc tool) and electrical performance models. The annual thermal and electrical yield achieved 86% and 89% of the simulated thermal and electrical yield, respectively.
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