| 1. |
- Guillén, Yolanda, et al.
(författare)
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Genomics of ecological adaptation in cactophilic Drosophila.
- 2014
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Ingår i: Genome Biology and Evolution. - : Oxford University Press (OUP). - 1759-6653. ; 7:1, s. 349-66
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Tidskriftsartikel (refereegranskat)abstract
- Cactophilic Drosophila species provide a valuable model to study gene-environment interactions and ecological adaptation. Drosophila buzzatii and Drosophila mojavensis are two cactophilic species that belong to the repleta group, but have very different geographical distributions and primary host plants. To investigate the genomic basis of ecological adaptation, we sequenced the genome and developmental transcriptome of D. buzzatii and compared its gene content with that of D. mojavensis and two other noncactophilic Drosophila species in the same subgenus. The newly sequenced D. buzzatii genome (161.5 Mb) comprises 826 scaffolds (>3 kb) and contains 13,657 annotated protein-coding genes. Using RNA sequencing data of five life-stages we found expression of 15,026 genes, 80% protein-coding genes, and 20% noncoding RNA genes. In total, we detected 1,294 genes putatively under positive selection. Interestingly, among genes under positive selection in the D. mojavensis lineage, there is an excess of genes involved in metabolism of heterocyclic compounds that are abundant in Stenocereus cacti and toxic to nonresident Drosophila species. We found 117 orphan genes in the shared D. buzzatii-D. mojavensis lineage. In addition, gene duplication analysis identified lineage-specific expanded families with functional annotations associated with proteolysis, zinc ion binding, chitin binding, sensory perception, ethanol tolerance, immunity, physiology, and reproduction. In summary, we identified genetic signatures of adaptation in the shared D. buzzatii-D. mojavensis lineage, and in the two separate D. buzzatii and D. mojavensis lineages. Many of the novel lineage-specific genomic features are promising candidates for explaining the adaptation of these species to their distinct ecological niches.
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| 2. |
- Kinsella, Cormac M., et al.
(författare)
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Programmed DNA elimination of germline development genes in songbirds
- 2019
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Ingår i: Nature Communications. - : NATURE PUBLISHING GROUP. - 2041-1723. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- In some eukaryotes, germline and somatic genomes differ dramatically in their composition. Here we characterise a major germline-soma dissimilarity caused by a germline-restricted chromosome (GRC) in songbirds. We show that the zebra finch GRC contains >115 genes paralogous to single-copy genes on 18 autosomes and the Z chromosome, and is enriched in genes involved in female gonad development. Many genes are likely functional, evidenced by expression in testes and ovaries at the RNA and protein level. Using comparative genomics, we show that genes have been added to the GRC over millions of years of evolution, with embryonic development genes bicc1 and trim71 dating to the ancestor of songbirds and dozens of other genes added very recently. The somatic elimination of this evolutionarily dynamic chromosome in songbirds implies a unique mechanism to minimise genetic conflict between germline and soma, relevant to antagonistic pleiotropy, an evolutionary process underlying ageing and sexual traits.
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| 3. |
- Pereira, Ricardo J., et al.
(författare)
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Mind the numt : Finding informative mitochondrial markers in a giant grasshopper genome
- 2021
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Ingår i: Journal of Zoological Systematics and Evolutionary Research. - : John Wiley & Sons. - 0947-5745 .- 1439-0469. ; 59:3, s. 635-645
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Tidskriftsartikel (refereegranskat)abstract
- The barcoding of the mitochondrial COX1 gene has been instrumental in cataloguing the tree of life, and in providing insights in the phylogeographic history of species. Yet, this strategy has encountered difficulties in major clades characterized by large genomes, which contain a high frequency of nuclear pseudogenes originating from the mitochondrial genome (numts). Here, we use the meadow grasshopper (Chorthippus parallelus), which possesses a giant genome of similar to 13 Gb, to identify mitochondrial genes that are underrepresented as numts, and test their use as informative phylogeographic markers. We recover the same full mitochondrial sequence using both whole genome and transcriptome sequencing, including functional protein-coding genes and tRNAs. We show that a region of the mitogenome containing the COX1 gene, typically used in DNA barcoding, has disproportionally higher diversity and coverage than the rest of the mitogenome, consistent with multiple insertions of that region into the nuclear genome. By designing new markers in regions of less elevated diversity and coverage, we identify two mitochondrial genes that are less likely to be duplicated as numts. We show that, while these markers show high levels of incomplete lineage sorting between subspecies, as expected for mitochondrial genes, genetic variation reflects their phylogeographic history accurately. These findings allow us to identify useful mitochondrial markers for future studies in C. parallelus, an important biological system for evolutionary biology. More generally, this study exemplifies how non-PCR-based methods using next-generation sequencing can be used to avoid numts in species characterized by large genomes, which have remained challenging to study in taxonomy and evolution.
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| 4. |
- Aleix-Mata, Gael, et al.
(författare)
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Development and characterization of 15 novel polymorphic microsatellite loci for two important bot flies (Diptera, Oestridae) by next-generation sequencing
- 2020
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Ingår i: Parasitology Research. - : Springer Nature. - 0932-0113 .- 1432-1955. ; 119:9, s. 2829-2835
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Tidskriftsartikel (refereegranskat)abstract
- Cephenemyia stimulatorandOestrus ovisare two important parasitic bot flies (Oestridae) species causing myiasis, with a potential negative impact on the welfare of the host. Using next-generation sequencing approach and bioinformatics tools, a large panel of possible microsatellites loci was obtained in both species. Primer pairs were designed for 15 selected microsatellite loci inC. stimulatorand other 15 loci inO. ovisfor PCR amplification. Loci amplification and analysis were performed in four populations of each species. The results demonstrated that all selected loci were polymorphic, with the number of alleles ranging from 2 to 6 per locus inC. stimulatorand 3 to 13 per locus inO. ovis. This is the first time to describe these microsatellite loci forC. stimulatorandO. ovis. These two sets of microsatellite markers could be further used for biogeographic and population genetics studies.
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| 5. |
- Camacho, Juan Pedro M., et al.
(författare)
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Satellitome comparison of two oedipodine grasshoppers highlights the contingent nature of satellite DNA evolution
- 2022
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Ingår i: BMC Biology. - : Springer Nature. - 1741-7007. ; 20:1
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundThe full catalog of satellite DNA (satDNA) within a same genome constitutes the satellitome. The Library Hypothesis predicts that satDNA in relative species reflects that in their common ancestor, but the evolutionary mechanisms and pathways of satDNA evolution have never been analyzed for full satellitomes. We compare here the satellitomes of two Oedipodine grasshoppers (Locusta migratoria and Oedaleus decorus) which shared their most recent common ancestor about 22.8 Ma ago.ResultsWe found that about one third of their satDNA families (near 60 in every species) showed sequence homology and were grouped into 12 orthologous superfamilies. The turnover rate of consensus sequences was extremely variable among the 20 orthologous family pairs analyzed in both species. The satDNAs shared by both species showed poor association with sequence signatures and motives frequently argued as functional, except for short inverted repeats allowing short dyad symmetries and non-B DNA conformations. Orthologous satDNAs frequently showed different FISH patterns at both intra- and interspecific levels. We defined indices of homogenization and degeneration and quantified the level of incomplete library sorting between species.ConclusionsOur analyses revealed that satDNA degenerates through point mutation and homogenizes through partial turnovers caused by massive tandem duplications (the so-called satDNA amplification). Remarkably, satDNA amplification increases homogenization, at intragenomic level, and diversification between species, thus constituting the basis for concerted evolution. We suggest a model of satDNA evolution by means of recursive cycles of amplification and degeneration, leading to mostly contingent evolutionary pathways where concerted evolution emerges promptly after lineages split.
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| 6. |
- Mora, Pablo, et al.
(författare)
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Satellitome Analysis in the Ladybird Beetle Hippodamia variegata(Coleoptera, Coccinellidae)
- 2020
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Ingår i: Genes. - : MDPI. - 2073-4425. ; 11:7
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Tidskriftsartikel (refereegranskat)abstract
- Hippodamia variegatais one of the most commercialized ladybirds used for the biological control of aphid pest species in many economically important crops. This species is the first Coccinellidae whose satellitome has been studied by applying new sequencing technologies and bioinformatics tools. We found that 47% of theH. variegatagenome is composed of repeated sequences. We identified 30 satellite DNA (satDNA) families with a median intragenomic divergence of 5.75% and A+T content between 45.6% and 74.7%. This species shows satDNA families with highly variable sizes although the most common size is 100-200 bp. However, we highlight the existence of a satDNA family with a repeat unit of 2 kb, the largest repeat unit described in Coleoptera. PCR amplifications for fluorescence in situ hybridization (FISH) probe generation were performed for the four most abundant satDNA families. FISH with the most abundant satDNA family as a probe shows its pericentromeric location on all chromosomes. This location is coincident with the heterochromatin revealed by C-banding and DAPI staining, also analyzed in this work. Hybridization signals for other satDNA families were located only on certain bivalents and the X chromosome. These satDNAs could be very useful as chromosomal markers due to their reduced location.
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| 7. |
- Zerbinato de Andrade Silva, Duilio Mazzoni, et al.
(författare)
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Long-term persistence of supernumerary B chromosomes in multiple species of Astyanax fish
- 2021
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Ingår i: BMC Biology. - : BioMed Central (BMC). - 1741-7007. ; 19
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Tidskriftsartikel (refereegranskat)abstract
- Background: Eukaryote genomes frequently harbor supernumerary B chromosomes in addition to the "standard" A chromosome set. B chromosomes are thought to arise as byproducts of genome rearrangements and have mostly been considered intraspecific oddities. However, their evolutionary transcendence beyond species level has remained untested.Results: Here we reveal that the large metacentric B chromosomes reported in several fish species of the genus Astyanax arose in a common ancestor at least 4 million years ago. We generated transcriptomes of A. scabripinnis and A. paranae 0B and 1B individuals and used these assemblies as a reference for mapping all gDNA and RNA libraries to quantify coverage differences between B-lacking and B-carrying genomes. We show that the B chromosomes of A. scabripinnis and A. paranae share 19 protein-coding genes, of which 14 and 11 were also present in the B chromosomes of A. bockmanni and A. fasciatus, respectively. Our search for B-specific single-nucleotide polymorphisms (SNPs) identified the presence of B-derived transcripts in B-carrying ovaries, 80% of which belonged to nobox, a gene involved in oogenesis regulation. Importantly, the B chromosome nobox paralog is expressed >30x more than the A chromosome paralog. This indicates that the normal regulation of this gene is altered in B-carrying females, which could potentially facilitate B inheritance at higher rates than Mendelian law prediction.Conclusions: Taken together, our results demonstrate the long-term survival of B chromosomes despite their lack of regular pairing and segregation during meiosis and that they can endure episodes of population divergence leading to species formation.
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| 8. |
- Aleix-Mata, Gael, et al.
(författare)
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The complete mitochondrial genome of Talpa aquitania (Talpidae; Insectivora), a mole species endemic to northern Spain and southern France
- 2020
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Ingår i: Molecular Biology Reports. - : SPRINGER. - 0301-4851 .- 1573-4978. ; 47:3, s. 2397-2403
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Tidskriftsartikel (refereegranskat)abstract
- The complete mitogenome sequence of Talpa aquitania, a recently described Talpa species, was assembled using whole-genome sequencing data. It varies in length from 16,776 to 16,846 bp, contains 13 protein-coding genes, two ribosomal RNA genes, 22 transfer RNA genes, one origin of L-strand replication, and a control region. In the control region, which varied from 1320 to 1390 bp, we identified the extended termination-associated sequence (ETAS-1 and ETAS-2) and the conserved sequence blocks (CSB-1, 2, 3, B, C, D, E, F). In addition, this region includes a 10 bp tandem repeat DNA sequence, with a variable number of repeats that suggest the existence of heteroplasmy. Phylogeny reconstructions based on Maximum Likelihood, Neighbor-joining and Bayesian inference analyses yielded phylogenies with similar topologies demonstrating that T. aquitania and T. occidentalis are sister species.
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| 9. |
- Borodin, Pavel, et al.
(författare)
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Mendelian nightmares : the germline-restricted chromosome of songbirds
- 2022
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Ingår i: Chromosome Research. - : Springer Nature. - 0967-3849 .- 1573-6849. ; 30:2-3, s. 255-272
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Forskningsöversikt (refereegranskat)abstract
- Germline-restricted chromosomes (GRCs) are accessory chromosomes that occur only in germ cells. They are eliminated from somatic cells through programmed DNA elimination during embryo development. GRCs have been observed in several unrelated animal taxa and show peculiar modes of non-Mendelian inheritance and within-individual elimination. Recent cytogenetic and phylogenomic evidence suggests that a GRC is present across the species-rich songbirds, but absent in non-passerine birds, implying that over half of all 10,500 bird species have extensive germline/soma genome differences. Here, we review recent insights gained from genomic, transcriptomic, and cytogenetic approaches with regard to the genetic content, phylogenetic distribution, and inheritance of the songbird GRC. While many questions remain unsolved in terms of GRC inheritance, elimination, and function, we discuss plausible scenarios and future directions for understanding this widespread form of programmed DNA elimination.
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| 10. |
- Castro, Jonathan Pena, et al.
(författare)
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Differential Expression of Genes Related to Sexual Determination Can Modify the Reproductive Cycle of Astyanax scabripinnis (Characiformes: Characidae) in B Chromosome Carrier Individuals
- 2019
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Ingår i: Genes. - : MDPI. - 2073-4425. ; 10:11
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Tidskriftsartikel (refereegranskat)abstract
- The species complex Astyanax scabripinnis is one of the most studied with respect to origin, distribution, and frequency of B chromosomes, and is considered a model organism for evolutionary studies. Research using population inferences about the occurrence and frequency of the B chromosome shows seasonal variation between sexes, which is associated with the presence of this supernumerary element. We hypothesized that the B chromosome could influence the sex ratio of these animals. Based on this assumption, the present work aimed to investigate if differences exist among levels of gene expression with qRT-PCR of the amh (associated with testicular differentiation) and foxl2a (associated with ovarian differentiation) genes between B-carrier and non-B-carrier individuals. The results showed that for the amh gene, the difference in expression between animals with B chromosomes was not accentuated compared to that in animals without this chromosome. Expression of foxl2a in B-carrier females, however, was reduced by 73.56% compared to females that lacked the B chromosome. Males had no difference in expression of the amh and foxl2a genes between carriers and non-carriers of the B chromosome. Results indicate that the presence of B chromosomes is correlated with the differential expression of sex-associated genes. An analysis of these results integrated with data from other studies on the reproductive cycle in the same species reveals that this difference in expression may be expanding the reproductive cycle of the species.
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