scholarly journals Drosophila Interspecific Hybridization Causes a Deregulation of the piRNA Pathway Genes

Genes ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 215
Author(s):  
Víctor Gámez-Visairas ◽  
Valèria Romero-Soriano ◽  
Joan Martí-Carreras ◽  
Eila Segarra-Carrillo ◽  
Maria Pilar García Guerreiro

Almost all eukaryotes have transposable elements (TEs) against which they have developed defense mechanisms. In the Drosophila germline, the main transposable element (TE) regulation pathway is mediated by specific Piwi-interacting small RNAs (piRNAs). Nonetheless, for unknown reasons, TEs sometimes escape cellular control during interspecific hybridization processes. Because the piRNA pathway genes are involved in piRNA biogenesis and TE control, we sequenced and characterized nine key genes from this pathway in Drosophila buzzatii and Drosophila koepferae species and studied their expression pattern in ovaries of both species and their F1 hybrids. We found that gene structure is, in general, maintained between both species and that two genes—armitage and aubergine—are under positive selection. Three genes—krimper, methyltransferase 2, and zucchini—displayed higher expression values in hybrids than both parental species, while others had RNA levels similar to the parental species with the highest expression. This suggests that the overexpression of some piRNA pathway genes can be a primary response to hybrid stress. Therefore, these results reinforce the hypothesis that TE deregulation may be due to the protein incompatibility caused by the rapid evolution of these genes, leading to a TE silencing failure, rather than to an underexpression of piRNA pathway genes.

Agriculture ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 306
Author(s):  
Tasanai Punjansing ◽  
Maliwan Nakkuntod ◽  
Somjit Homchan ◽  
Phithak Inthima ◽  
Anupan Kongbangkerd

This study aimed at assessing the hybridization feasibility and evaluating genetic fidelity of the hybrid seedlings originated from Phaius mishmensis (Lindl. and Paxton) Rchb. f. and P. tankervilliae (Banks) Blume. Intra- and interspecific hybridization between Phaius mishmensis (Lindl. and Paxton) Rchb. f. and P. tankervilliae (Banks) Blume were examined to establish the primary hybrid, observe their cross ability and identify the F1 hybrids using sequence-characterized amplified region (SCAR) markers. Self-incompatibility and cross ability of P. mishmensis and P. tankervilliae were tested before starting the breeding program. Results showed that they were self-compatible orchids. The interspecific hybridization between P. mishmensis and P. tankervilliae was achieved with the highest pod setting (80%), seed germination percentage (94.8%) and the rate of protocorm development into mature seedlings (stage 6) (10.6%), but the smallest size of embryo with width 46.5 μm, length 67.3 μm was also observed when P. mishmensis was taken as the female parent. A comparative study on leaf morphology and anatomy of plantlets regenerated from intra- and interspecific hybrids of P. mishmensis and P. tankervilliae showed a transitional character to the parental species. Herein, the presence of interspecific hybrids between P. mishmensis and P. tankervilliae, as well as their reciprocal cross, was verified using Pmis524 SCAR markers developed by the decamer primer.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Weitao Chen ◽  
Ming Zou ◽  
Yuefei Li ◽  
Shuli Zhu ◽  
Xinhui Li ◽  
...  

AbstractGenome complexity such as heterozygosity may heavily influence its de novo assembly. Sequencing somatic cells of the F1 hybrids harboring two sets of genetic materials from both of the paternal and maternal species may avoid alleles discrimination during assembly. However, the feasibility of this strategy needs further assessments. We sequenced and assembled the genome of an F1 hybrid between Silurus asotus and S. meridionalis using the SequelII platform and Hi-C scaffolding technologies. More than 300 Gb raw data were generated, and the final assembly obtained 2344 scaffolds composed of 3017 contigs. The N50 length of scaffolds and contigs was 28.55 Mb and 7.49 Mb, respectively. Based on the mapping results of short reads generated for the paternal and maternal species, each of the 29 chromosomes originating from S. asotus and S. meridionalis was recognized. We recovered nearly 94% and 96% of the total length of S. asotus and S. meridionalis. BUSCO assessments and mapping analyses suggested that both genomes had high completeness and accuracy. Further analyses demonstrated the high collinearity between S. asotus, S. meridionalis, and the related Pelteobagrus fulvidraco. Comparison of the two genomes with that assembled only using the short reads from non-hybrid parental species detected a small portion of sequences that may be incorrectly assigned to the different species. We supposed that at least part of these situations may have resulted from mitotic recombination. The strategy of sequencing the F1 hybrid genome can recover the vast majority of the parental genomes and may improve the assembly of complex genomes.


2021 ◽  
Vol 22 (7) ◽  
pp. 3406
Author(s):  
Robert L. Medcalf ◽  
Charithani B. Keragala

The fibrinolytic system provides an essential means to remove fibrin deposits and blood clots. The actual protease responsible for this is plasmin, formed from its precursor, plasminogen. Fibrin is heralded as it most renowned substrate but for many years plasmin has been known to cleave many other substrates, and to also activate other proteolytic systems. Recent clinical studies have shown that the promotion of plasmin can lead to an immunosuppressed phenotype, in part via its ability to modulate cytokine expression. Almost all immune cells harbor at least one of a dozen plasminogen receptors that allows plasmin formation on the cell surface that in turn modulates immune cell behavior. Similarly, a multitude of pathogens can also express their own plasminogen activators, or contain surface proteins that provide binding sites host plasminogen. Plasmin formed under these circumstances also empowers these pathogens to modulate host immune defense mechanisms. Phylogenetic studies have revealed that the plasminogen activating system predates the appearance of fibrin, indicating that plasmin did not evolve as a fibrinolytic protease but perhaps has its roots as an immune modifying protease. While its fibrin removing capacity became apparent in lower vertebrates these primitive under-appreciated immune modifying functions still remain and are now becoming more recognised.


1987 ◽  
Vol 40 (3) ◽  
pp. 257 ◽  
Author(s):  
WR Knibb ◽  
PD East ◽  
JSF Barker

Chromosome 2 inversion, Est-l and Est-2 haplotype frequencies were determined for 19 wild D. buzzatii collections from the known range of this species in Australia. Three different chromosome 2 sequences (ST, j, j z3) were polymorphic across the collections. They occurred at overall frequencies which approximated those in the ancestral New World and colonized Old World populations, which indicated that no radical genetic change was associated with the colonization of Australia by D. buzzatii. Linkage disequilibria of Est-l and Est-2 alleles with the inversions tended to be strong, and consistent in direction, in almost all collections. The distributions of conditional allele frequencies within the different inversions were consistent with stochastic historical explanations for the linkage disequilibria. Significant linkage disequilibria between Est-l and Est-2 were evident after correcting for the inversions, but these disequilibria largely were restricted to southern (higher latitude) populations, and were inconsistent in direction among the collections. Hence, population bottlenecks may underlie these genic disequilibria.


2005 ◽  
Vol 130 (5) ◽  
pp. 711-715 ◽  
Author(s):  
Nicholi Vorsa ◽  
James J. Polashock

The flavonoids of american cranberry (Vaccinium macrocarpon Ait.) are documented to be beneficial for human health. Among their benefits is a high antioxidant potential, with anthocyanin glycosides being the main contributors. Flavonoid glucose conjugates are reported to be more bioavailable than those with other sugar conjugates. The anthocyanin glycosides of V. macrocarpon fruit are mainly galactosides and arabinosides of the aglycones, cyanidin and peonidin, with less than 8% glucosides. In contrast, the fruit anthocyanins of another cranberry species, V. oxycoccus L. were found to be largely glucosides of cyanidin and peonidin. Interspecific hybrids between these two species were intermediate to the parental species in the proportion of fruit anthocyanin glucosides. About half the progeny (1:1 segregation) in a backcross population (to V. macrocarpon) maintained the relatively high anthocyanin glucoside ratio. In this study, we demonstrate the genetic manipulation of anthocyanin glycosylation in cranberry using interspecific hybridization, resulting in dramatically increased glucose-conjugated anthocyanins.


2021 ◽  
Vol 9 (08) ◽  
pp. 334-341
Author(s):  
Shailesh Kapadia ◽  
◽  
Kirti Patel ◽  
P.K. Patel ◽  
Mempal D. ◽  
...  

The heterosis and combining ability studies were conducted by utilizing modified Line X Tester mating design involving 6 Lines and 9 testers of Okra [Abelmoschus esculentus (L.) Moench]. The breeding material involving fifty four F1 hybrids along with 15 parents with one commercial check were evaluated during Kharif 2020 in a Randomized Block Design (R.B.D.) with three replications at Research Centre of Goldking Biogene Private Limited with an aim to estimate the magnitude of heterosis and to identify the good parents and good hybrid combinations for pod yield and other quantitative traits. Among the parents GKOF-1, GKOF-5 and GOM-7 were found to be good general combiners for pod yield per plot. Among the lines GKOF-3, GKOF-4 and GKOF-6 and testers GKOM-4, GKOM-5, GKOM-7 and GKOM-9 were found to be involved in exhibiting significant sca effects for almost all characters. Among the crosses GKOF-2 X GKOM-5, GKOF-1 X GKOM-8 and GKOF-6 X GKOM-7 exhibited high per se performance for pod yield per plot. Further the cross GKOF-1 X GKOM-7, GKOF-4 X GKOM-9 and GKOF-6 X GKOM-4 revealed highest positively significant sca effects for pod yield per plot.


2019 ◽  
Vol 30 (2) ◽  
pp. 47-54
Author(s):  
M.R. Ferrari ◽  
E.J. Greizerstein ◽  
L. Poggio

In this work the relationship between genome size of Glandularia species and the meiotic configurations found in their hybrids are discussed. Glandularia incisa (Hook.) Tronc., growing in two localities of Corrientes and Córdoba provinces, Argentina, with different ecological conditions, showed inter-population variability of the 2C-value. The DNA content found in the Corrientes locality (2.41 pg) was higher than that obtained in the Córdoba locality (2.09 pg) which has more stressful environmental conditions than the former. These values are statistically different from those that were found in Glandularia pulchella (Sweet) Tronc. from Corrientes (1.43 pg) and in Glandularia perakii Cov. et Schn from Córdoba (1.47 pg). The DNA content of the diploid F1 hybrids, G. pulchella × G. incisa and G. perakii × G. incisa, differed statistically from the DNA content of the parental species, being intermediate between them. Differences in the frequency of pairing of homoeologous chromosomes were observed in the hybrids; these differences cannot be explained by differences in genome size since hybrids with similar DNA content differ significantly in their meiotic behavior. On the other hand, the differences in the DNA content between the parental species justify the presence of a high frequency of heteromorphic open and closed bivalents and univalents with different size in the hybrids. Key words: Intra-specific DNA content variability, homoeologous pairing, heteromorphic bivalents


2021 ◽  
Author(s):  
Amanda Smith ◽  
Levi Morran ◽  
Meleah A. Hickman

The ability to generate genetic variation facilitates rapid adaptation in stressful environments. The opportunistic fungal pathogen Candida albicans frequently undergoes large-scale genomic changes, including aneuploidy and loss-of heterozygosity (LOH), following exposure to host environments. However, the specific host factors inducing C. albicans genome instability remain largely unknown. Here, we leveraged the genetic tractability of nematode hosts to investigate whether innate immune components, including antimicrobial peptides (AMPs) and reactive oxygen species (ROS), induced host-associated C. albicans genome instability. C. albicans associated with immunocompetent hosts carried multiple large-scale genomic changes including LOH, whole chromosome, and segmental aneuploidies. In contrast, C. albicans associated with immunocompromised hosts deficient in AMPs or ROS production had reduced LOH frequencies and fewer, if any, additional genomic changes. To evaluate if extensive host-induced genomic changes had long-term consequences for C. albicans adaptation, we experimentally evolved C. albicans in either immunocompetent or immunocompromised hosts and selected for increased virulence. C. albicans evolved in immunocompetent hosts rapidly increased virulence, but not in immunocompromised hosts. Taken together, this work suggests that host-produced ROS and AMPs induces genotypic plasticity in C. albicans which facilitates rapid evolution.


2019 ◽  
Vol 286 (1913) ◽  
pp. 20191621 ◽  
Author(s):  
O. M. Selz ◽  
O. Seehausen

The role of interspecific hybridization in evolution is still being debated. Interspecific hybridization has been suggested to facilitate the evolution of ecological novelty, and hence the invasion of new niches and adaptive radiation when ecological opportunity is present beyond the parental species niches. On the other hand, hybrids between two ecologically divergent species may perform less well than parental species in their respective niches because hybrids would be intermediate in performance in both niches. The evolutionary consequences of hybridization may hence be context-dependent, depending on whether ecological opportunities, beyond those of the parental species, do or do not exist. Surprisingly, these complementary predictions may never have been tested in the same experiment in animals. To do so, we investigate if hybrids between ecologically distinct cichlid species perform less well than the parental species when feeding on food either parent is adapted to, and if the same hybrids perform better than their parents when feeding on food none of the species are adapted to. We generated two first-generation hybrid crosses between species of African cichlids. In feeding efficiency experiments we measured the performance of hybrids and parental species on food types representing both parental species niches and additional ‘novel’ niches, not used by either of the parental species but by other species in the African cichlid radiations. We found that hybrids can have higher feeding efficiencies on the ‘novel’ food types but typically have lower efficiencies on parental food types when compared to parental species. This suggests that hybridization can generate functional variation that can be of ecological relevance allowing the access to resources outside of either parental species niche. Hence, we provide support for the hypothesis of ecological context-dependency of the evolutionary impact of interspecific hybridization.


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