scholarly journals Selection index in Drosophila melanogaster Meig. progeny after exposure to acute γ-irradiation

2019 ◽  
Vol 25 ◽  
pp. 86-91
Author(s):  
D. O. Skorobagatko ◽  
V. Yu. Strashnyuk ◽  
A. A. Mazilov

Aim. The purpose of investigation was to study the intensity of selection in two generations of Drosophila melanogaster Meig. after acute g-irradiation. Methods. Experiments were conducted on a wild-type Oregon-R strain. Adult flies in the age of 3 days were irradiated with bremsstrahlung gamma quanta at doses of 8 Gy, 16 Gy and 25 Gy on a linear accelerator of electrons LAE-10. Irradiated (O) and non-irradiated (K) flies were crossed in four different combinations: K×K (control), O×K, K×O, and O×O. The selection index were calculated from the Crow formula based on fertility, mortality/survival in pre-productive period of development. Results. Selection indexes in the generation F1 after irradiation grow in proportion to the dose received: at embryonal stage 2.0–7.2 times, at post-embryonic development – in 1.3–7.6 times. In the generation F2, the indexes of selection were significantly reduced. Conclusions. The selection pressure is substantially increased in the first generation after g-irradiation and weakens, approaching the control level and lower in F2. Keywords: Drosophila melanogaster Meig., fertility, embryonic mortality, pupae mortality, ionizing radiation.

2021 ◽  
Vol 12 ◽  
Author(s):  
Chao Ouyang ◽  
Wei Liu ◽  
Silan Chen ◽  
Huimin Zhao ◽  
Xinyan Chen ◽  
...  

Glyphosate-resistant crops developed by the CP4-EPSPS gene from Agrobacterium have been planted on a massive scale globally, which benefits from the high efficiency and broad spectrum of glyphosate in weed control. Some glyphosate-resistant (GR) genes from microbes have been reported, which might raise biosafety concerns. Most of them were obtained through a hygromycin-HPT transformation system. Here we reported the plant source with 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene from goosegrass endowed rice with high resistance to glyphosate. The integrations and inheritability of the transgenes in the rice genome were investigated within two generations. The EiEPSPS transgenic plants displayed similar growth and development to wild type under no glyphosate selection pressure but better reproductive performance under lower glyphosate selection pressure. Furthermore, we reconstructed a binary vector pCEiEPSPS and established the whole stage glyphosate selection using the vector. The Glyphosate-pCEiEPSPS selection system showed a significantly higher transformation efficiency compared with the hygromycin-HPT transformation system. Our results provided a promising alternative gene resource to the development of GR plants and also extended the plant transformation toolbox.


2021 ◽  
Vol 1 (3) ◽  
pp. 59-64
Author(s):  
N. Kozak ◽  
L. Atramentova

In human populations natural selection is shifting to the side of prenatal development and appears as negative outcomes of pregnancies such as spontaneous abortions, ectopic pregnancies and stillbirths. Therefore, it is important to study dynamics of changes in reproductive characteristics and selection indexes of the populations in order to predict possible problems and numbers of genetic burden in the populations. Ukraine is poorly studied in this area. The aim of the study was to investigate indicators which characterize the population structure of Lutsk city, the intensity of natural selection, migration and their dynamics in two generations. 583 post-reproductive age females were anonymously questioned. Age, places of birth of the couple, the number of pregnancies and their outcomes were considered. Results show that natural selection indexes (Crow’s indexes) are decreasing from the first generation (0,26) to the second (0,20). Migration coefficients in the population of Lutsk decreased from 0.89 to 0.82 per generation and show intensive urbanization of the city for the studied time. The efficiency of the migration is low, since the biggest number of migrants come from the villages of the Volyn region (45% for first generations and 64% for the second one), or adjacent regions of Ukraine (35% and 27%, respectively). The population of Lutsk has a narrowed type of reproduction, where average number of offspring per female equal 1,86 for the first generation and 1,73 for the second generation.


Author(s):  
D. A. Skorobahatko ◽  
V. Yu. Strashnyuk ◽  
A. A. Mazilov

Aim. The purpose of investigation was to study the peculiarities of homologous conjugation of polytene chromosomes in the salivary glands of larvae in Drosophila melanogaster offspring after exposure to acute γ-irradiation. Methods. Experiments were carried out on wild type Oregon-R strain. Three-day-old flies were irradiated by brake gamma rays on the linear electron accelerator LEA-10. The dose rate was 0.4 Gr/sec.The effects of acute γ-radiation at doses of 8 Gr and 16 Gr were studied. Giant chromosomes were investigated in squashed preparations of the salivary glands stained by acetoorcein. Preparations were obtained from the females at the end of third larva stage. Results. The decrease at 41.5 % in asynapsis frequency of homologous chromosomes in salivary gland cells of larvae in Drosophila F1 progeny after γ-irradiation at the dose of 8 Gr was shown. No effect was observed at the dose of 16 Gr. Analysis of variance showed with a high degree of significance (Fφ = 53, p < 0,001) the influence of gradations of factor on the frequency of violations of conjugation of homologous in Drosophila polytene chromosomes. Conclusions. The results suggest a possible effect of gamma-radiation on the trans-interaction of loci of homologous chromosomes due to the changes in the asynapsis frequency. Keywords: giant chromosomes, spontaneous asynapsis, trans-interactions, ionizing radiation.


2018 ◽  
Author(s):  
Daria A. Skorobagatko ◽  
Alexey A. Mazilov ◽  
Volodymyr Yu. Strashnyuk

AbstractThe purpose of investigation was to study the effect of acute γ-irradiation of parent adults on the endoreduplication in Drosophila melanogaster progeny. As a material used Oregon-R strain. Virgin females and males of Drosophila adults at the age of 3 days were exposed at the doses of 8, 16 and 25 Gy. Giant chromosomes were studied at late 3rd instar larvae by cytomorphometric method. The average polyteny in males increased at the dose of 8 Gy by 10.6%, at the dose of 25 Gy by 7.4%, and did not change at the dose of 16 Gy. In females, the polyteny did not differ from the control value irrespective of the irradiation dose. The statistical impact power of sex on polyteny was 4,9%, the radiation impact was 26,8%. The enhancement of endoruplication is considered as a consequence of an increasing selection pressure after irradiation.


2019 ◽  
Vol 476 (22) ◽  
pp. 3521-3532
Author(s):  
Eric Soubeyrand ◽  
Megan Kelly ◽  
Shea A. Keene ◽  
Ann C. Bernert ◽  
Scott Latimer ◽  
...  

Plants have evolved the ability to derive the benzenoid moiety of the respiratory cofactor and antioxidant, ubiquinone (coenzyme Q), either from the β-oxidative metabolism of p-coumarate or from the peroxidative cleavage of kaempferol. Here, isotopic feeding assays, gene co-expression analysis and reverse genetics identified Arabidopsis 4-COUMARATE-COA LIGASE 8 (4-CL8; At5g38120) as a contributor to the β-oxidation of p-coumarate for ubiquinone biosynthesis. The enzyme is part of the same clade (V) of acyl-activating enzymes than At4g19010, a p-coumarate CoA ligase known to play a central role in the conversion of p-coumarate into 4-hydroxybenzoate. A 4-cl8 T-DNA knockout displayed a 20% decrease in ubiquinone content compared with wild-type plants, while 4-CL8 overexpression boosted ubiquinone content up to 150% of the control level. Similarly, the isotopic enrichment of ubiquinone's ring was decreased by 28% in the 4-cl8 knockout as compared with wild-type controls when Phe-[Ring-13C6] was fed to the plants. This metabolic blockage could be bypassed via the exogenous supply of 4-hydroxybenzoate, the product of p-coumarate β-oxidation. Arabidopsis 4-CL8 displays a canonical peroxisomal targeting sequence type 1, and confocal microscopy experiments using fused fluorescent reporters demonstrated that this enzyme is imported into peroxisomes. Time course feeding assays using Phe-[Ring-13C6] in a series of Arabidopsis single and double knockouts blocked in the β-oxidative metabolism of p-coumarate (4-cl8; at4g19010; at4g19010 × 4-cl8), flavonol biosynthesis (flavanone-3-hydroxylase), or both (at4g19010 × flavanone-3-hydroxylase) indicated that continuous high light treatments (500 µE m−2 s−1; 24 h) markedly stimulated the de novo biosynthesis of ubiquinone independently of kaempferol catabolism.


2019 ◽  
Author(s):  
Zac Wylde ◽  
Foteini Spagopoulou ◽  
Amy K Hooper ◽  
Alexei A Maklakov ◽  
Russell Bonduriansky

Individuals within populations vary enormously in mortality risk and longevity, but the causes of this variation remain poorly understood. A potentially important and phylogenetically widespread source of such variation is maternal age at breeding, which typically has negative effects on offspring longevity. Here, we show that paternal age can affect offspring longevity as strongly as maternal age does, and that breeding age effects can interact over two generations in both matrilines and patrilines. We manipulated maternal and paternal ages at breeding over two generations in the neriid fly Telostylinus angusticollis. To determine whether breeding age effects can be modulated by the environment, we also manipulated larval diet and male competitive environment in the first generation. We found separate and interactive effects of parental and grandparental ages at breeding on descendants’ mortality rate and lifespan in both matrilines and patrilines. These breeding age effects were not modulated by grandparental larval diet quality or competitive environment. Our findings suggest that variation in maternal and paternal ages at breeding could contribute substantially to intra-population variation in mortality and longevity.


Genetics ◽  
1984 ◽  
Vol 106 (2) ◽  
pp. 249-265
Author(s):  
Jym Mohler ◽  
Mary Lou Pardue

ABSTRACT The region containing subdivisions 93C, 93D and 93E on chromosome 3 of Drosophila melanogaster has been screened for visible and lethal mutations. Treatment with three mutagens, γ irradiation, ethyl methanesulfonate and diepoxybutane, has produced mutations that fall into 20 complementation groups, including the previously identified ebony locus. No point mutations affecting the heat shock locus in 93D were detected; however, a pair of deficiencies that overlap in the region of this locus was isolated. Flies heterozygous in trans for this pair of deficiencies are capable of producing all of the major heat shock puffs (except 93D) and the major heat shock proteins. In addition, these flies show recovery of normal protein synthesis following a heat shock.


Genetics ◽  
1996 ◽  
Vol 143 (3) ◽  
pp. 1339-1347
Author(s):  
Alfred M Handler ◽  
Sheilachu P Gomez

Abstract Function of the Drosophila melanogaster hobo transposon in tephritid species was tested in transient embryonic excision assays. Wild-type and mutant strains of Anastrepha suspensa, Bactrocera dorsalis, B. cucurbitae, Ceratitis capitata, and Toxotrypana curvicauda all supported hobo excision or deletion both in the presence and absence of co-injected hobo transposase, indicating a permissive state for hobo mobility and the existence of endogenous systems capable of mobilizing hobo. In several strains hobo helper reduced excision. Excision depended on hobo sequences in the indicator plasmid, though almost all excisions were imprecise and the mobilizing systems appear mechanistically different from hobo. hobe-related sequences were identified in all species except T. curvicauda. Parsimony analysis yielded a subgroup including the B. cucurbitae and C. capitata sequences along with hobo and Hermes, and a separate, more divergent subgroup including the A. suspensa and B. dorsalis sequences. All of the sequences exist as multiple genomic elements, and a deleted form of the B. cucurbitae element exists in B. dorsalis. The hobo-related sequences are probably members of the hAT transposon family with some evolving from distant ancestor elements, while others may have originated from more recent horizontal transfers.


2021 ◽  
Author(s):  
Biz R. Turnell ◽  
Luisa Kumpitsch ◽  
Klaus Reinhardt

AbstractSperm aging is accelerated by the buildup of reactive oxygen species (ROS), which cause oxidative damage to various cellular components. Aging can be slowed by limiting the production of mitochondrial ROS and by increasing the production of antioxidants, both of which can be generated in the sperm cell itself or in the surrounding somatic tissues of the male and female reproductive tracts. However, few studies have compared the separate contributions of ROS production and ROS scavenging to sperm aging, or to cellular aging in general. We measured reproductive fitness in two lines of Drosophila melanogaster genetically engineered to (1) produce fewer ROS via expression of alternative oxidase (AOX), an alternative respiratory pathway; or (2) scavenge fewer ROS due to a loss-of-function mutation in the antioxidant gene dj-1β. Wild-type females mated to AOX males had increased fecundity and longer fertility durations, consistent with slower aging in AOX sperm. Contrary to expectations, fitness was not reduced in wild-type females mated to dj-1β males. Fecundity and fertility duration were increased in AOX and decreased in dj-1β females, indicating that female ROS levels may affect aging rates in stored sperm and/or eggs. Finally, we found evidence that accelerated aging in dj-1β sperm may have selected for more frequent mating. Our results help to clarify the relative roles of ROS production and ROS scavenging in the male and female reproductive systems.


Genetics ◽  
1974 ◽  
Vol 76 (2) ◽  
pp. 289-299
Author(s):  
Margaret McCarron ◽  
William Gelbart ◽  
Arthur Chovnick

ABSTRACT A convenient method is described for the intracistronic mapping of genetic sites responsible for electrophoretic variation of a specific protein in Drosophila melanogaster. A number of wild-type isoalleles of the rosy locus have been isolated which are associated with the production of electrophoretically distinguishable xanthine dehydrogenases. Large-scale recombination experiments were carried out involving null enzyme mutants induced on electrophoretically distinct wild-type isoalleles, the genetic basis for which is followed as a nonselective marker in the cross. Additionally, a large-scale recombination experiment was carried out involving null enzyme rosy mutants induced on the same wild-type isoallele. Examination of the electrophoretic character of crossover and convertant products recovered from the latter experiment revealed that all exhibited the same parental electrophoretic character. In addition to documenting the stability of the xanthine dehydrogenase electrophoretic character, this observation argues against a special mutagenesis hypothesis to explain conversions resulting from allele recombination studies.


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