The Experts below are selected from a list of 35487 Experts worldwide ranked by ideXlab platform
Carlos Caceres - One of the best experts on this subject based on the ideXlab platform.
-
cryopreservation of the mediterranean fruit fly diptera tephritidae vienna 8 genetic sexing strain no effect on large scale production of high quality sterile males for sit applications
PLOS ONE, 2019Co-Authors: Adly M M Abdalla, Jose S Meza, Kostas Bourtzis, Ulysses Sto Tomas, Carlos CaceresAbstract:: The sterile insect technique (SIT) integrated in area-wide integrated pest management (AW-IPM) programmes is being used for the successful management of the Mediterranean fruit fly Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) which is a horticultural pest of economic importance in tropical and subtropical countries. All programmes with an SIT component are using the VIENNA genetic sexing strains (GSS), mainly the VIENNA 8 GSS, which have been developed by applying classical genetic approaches. The VIENNA 8 GSS carries two selectable markers, the white pupae and the temperature sensitive Lethal Genes, which allows the production and release of only males thus increasing the biological efficiency and cost effectiveness of SIT applications. However, mass rearing may affect quality traits of the GSS, in which case replenishment of the colony with wild flies is recommended, a process which is tedious and time consuming. We previously reported the development of a cryopreservation protocol for the VIENNA 8D53+ strain. In the present study, we report on the evaluation of the cryopreserved strain VIENNA 8D53+/Cryo-228L, reared under semi mass rearing conditions, for production parameters, quality control indices and mating competitiveness of males, in a comparative way with the non-cryopreserved VIENNA 8D53+ strain, against wild type males. The VIENNA 8D53+ and VIENNA 8D53+/Cryo-228L strains were similar for production parameters viz. egg production, pupal production, pupal recovery, and quality control indices like fly emergence, sex ratio and flight ability. Males from both strains were equally competitive with males of the wild type strain in achieving mating with wild type females under field cage conditions. Results are discussed in the context of cryopreservation as a potential backup strategy for refreshing the mass rearing colony with biological material from a cryopreserved stock.
-
comparison of classical and transgenic genetic sexing strains of mediterranean fruit fly diptera tephritidae for application of the sterile insect technique
PLOS ONE, 2018Co-Authors: Jose S Meza, Georgios A Kyritsis, Marc J. B. Vreysen, Kostas Bourtzis, Carlos CaceresAbstract:The development of genetic sexing strains (GSSs) based on classical genetic approaches has revolutionized the application of the sterile insect technique (SIT) against the Mediterranean fruit fly Ceratitis capitata (Wiedemann) (Diptera: Tephritidae). The global use of Mediterranean fruit fly GSS for SIT applications as part of area-wide integrated pest management (AW-IPM) programmes is testimony to their effectiveness. During recent years, transgenic sexing strains (TSSs) have been developed through genetic engineering techniques offering the possibility to produce male-only progeny by introducing female embryonic Lethal Genes and to increase the efficacy to identify released sterile males by means of the expression of fluorescent transgene markers. Here, we present a comparative analysis of two Mediterranean fruit fly strains: the classical GSS VIENNA 8D53-/Toliman and the transgenic FSEL#32. The strains were compared for production efficiency and quality control indices under semi mass-rearing conditions, response to sterilizing irradiation doses, male mating performance in walk-in field cages, and production cost of male-only pupae. The results showed that, the FSEL #32 TSS had a similar fecundity but a higher production of male-only pupae than the VIENNA 8D53-/Toliman GSS. For some of the quality control parameters tested, such as pupal weight and survival under starvation conditions, the FSEL #32 TSS was inferior to the VIENNA 8D53-/Toliman GSS. Both the transgenic and the classical genetic sexing strains have shown acceptable and similar mating competitiveness when compared with wild males for mating with wild females. The cost production for both strains is similar but the FSEL#32 TSS may potentially be more cost effective at higher production levels. The results are discussed in the context of incorporating the transgenic strain for SIT application.
Jose S Meza - One of the best experts on this subject based on the ideXlab platform.
-
cryopreservation of the mediterranean fruit fly diptera tephritidae vienna 8 genetic sexing strain no effect on large scale production of high quality sterile males for sit applications
PLOS ONE, 2019Co-Authors: Adly M M Abdalla, Jose S Meza, Kostas Bourtzis, Ulysses Sto Tomas, Carlos CaceresAbstract:: The sterile insect technique (SIT) integrated in area-wide integrated pest management (AW-IPM) programmes is being used for the successful management of the Mediterranean fruit fly Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) which is a horticultural pest of economic importance in tropical and subtropical countries. All programmes with an SIT component are using the VIENNA genetic sexing strains (GSS), mainly the VIENNA 8 GSS, which have been developed by applying classical genetic approaches. The VIENNA 8 GSS carries two selectable markers, the white pupae and the temperature sensitive Lethal Genes, which allows the production and release of only males thus increasing the biological efficiency and cost effectiveness of SIT applications. However, mass rearing may affect quality traits of the GSS, in which case replenishment of the colony with wild flies is recommended, a process which is tedious and time consuming. We previously reported the development of a cryopreservation protocol for the VIENNA 8D53+ strain. In the present study, we report on the evaluation of the cryopreserved strain VIENNA 8D53+/Cryo-228L, reared under semi mass rearing conditions, for production parameters, quality control indices and mating competitiveness of males, in a comparative way with the non-cryopreserved VIENNA 8D53+ strain, against wild type males. The VIENNA 8D53+ and VIENNA 8D53+/Cryo-228L strains were similar for production parameters viz. egg production, pupal production, pupal recovery, and quality control indices like fly emergence, sex ratio and flight ability. Males from both strains were equally competitive with males of the wild type strain in achieving mating with wild type females under field cage conditions. Results are discussed in the context of cryopreservation as a potential backup strategy for refreshing the mass rearing colony with biological material from a cryopreserved stock.
-
comparison of classical and transgenic genetic sexing strains of mediterranean fruit fly diptera tephritidae for application of the sterile insect technique
PLOS ONE, 2018Co-Authors: Jose S Meza, Georgios A Kyritsis, Marc J. B. Vreysen, Kostas Bourtzis, Carlos CaceresAbstract:The development of genetic sexing strains (GSSs) based on classical genetic approaches has revolutionized the application of the sterile insect technique (SIT) against the Mediterranean fruit fly Ceratitis capitata (Wiedemann) (Diptera: Tephritidae). The global use of Mediterranean fruit fly GSS for SIT applications as part of area-wide integrated pest management (AW-IPM) programmes is testimony to their effectiveness. During recent years, transgenic sexing strains (TSSs) have been developed through genetic engineering techniques offering the possibility to produce male-only progeny by introducing female embryonic Lethal Genes and to increase the efficacy to identify released sterile males by means of the expression of fluorescent transgene markers. Here, we present a comparative analysis of two Mediterranean fruit fly strains: the classical GSS VIENNA 8D53-/Toliman and the transgenic FSEL#32. The strains were compared for production efficiency and quality control indices under semi mass-rearing conditions, response to sterilizing irradiation doses, male mating performance in walk-in field cages, and production cost of male-only pupae. The results showed that, the FSEL #32 TSS had a similar fecundity but a higher production of male-only pupae than the VIENNA 8D53-/Toliman GSS. For some of the quality control parameters tested, such as pupal weight and survival under starvation conditions, the FSEL #32 TSS was inferior to the VIENNA 8D53-/Toliman GSS. Both the transgenic and the classical genetic sexing strains have shown acceptable and similar mating competitiveness when compared with wild males for mating with wild females. The cost production for both strains is similar but the FSEL#32 TSS may potentially be more cost effective at higher production levels. The results are discussed in the context of incorporating the transgenic strain for SIT application.
Francesc Mestres - One of the best experts on this subject based on the ideXlab platform.
-
viabilities of d subobscura homo and heterokaryotypes at optimal and stress temperatures ii seasonal component analysis
Hereditas, 2010Co-Authors: Goran Zivanovic, Francesc MestresAbstract:Here we report the viability of natural chromosomal O-inversion structural homo- and heterokaryotypes in a population of D. subobscura from Avala Mountain, Serbia, subjected to cold and heat stress during spring 2004. These results were compared with those observed in the same population in September 2004. We detected protection of a great number of Lethal Genes in O-chromosome Lethal heterozygous combinations, independently of inversion backgrounds and temperature stress. The positive epistatic interactions of mildly-deleterious Genes observed only in O-inversion heterokaryotypes (at distinct temperatures) and Lethal Genes in O-inversion homokaryotypes (under temperature stress only) could be responsible for reducing the genetic load. The seasonal fluctuations in frequencies of several chromosomal arrangements and karyotypes indicate a seasonal adaptation to changeable environmental conditions. The sample of D. subobscura collected in spring 2004 was tolerant to cold but not to heat, and these results point to tolerance to extreme low temperatures, possibly as a result of natural selection. Also, a non-random distribution of distinct combinations of viability classes among several O-inversion karyotypes (under both optimal conditions and heat stress) was observed. This observation could be taken as evidence of co-adaptation: different capacities of several O-inversion karyotypes with different combinations of Genes to tolerate a range of temperatures. We conclude that frequency-dependent and supergene selection are balancing selection mechanisms and are responsible for the protection of chromosomal inversions in natural populations of D. subobscura.
-
viabilities of drosophila subobscura homo and heterokaryotypes at optimal and stress temperatures i analysis over several years
Hereditas, 2010Co-Authors: Goran Zivanovic, Francesc MestresAbstract:The interactions of Lethal and non-Lethal Genes and their contributions to the viability of Drosophila inversion karyotypes are not well understood. This is especially true under variable environmental conditions. Here we examine the viability of natural chromosomal O-inversion homo- and heterokaryotypes in a D. subobscura population from Avala Mountain, Serbia. The observations we report were performed at a range of temperatures over several years. The heterotic effect of O-Lethal heterozygotes on viability was found to be independent of the effects of inversion backgrounds and temperature. Positive epistatic interactions of Lethal, mildly deleterious (subvital) and quasinormal (normal) Genes were found in O-inversions in heterokaryotypes but not in homokaryotypes. These interactions were independent of temperature. This finding could explain the limitation of the genetic load in D. subobscura populations. In the population analyzed, annual fluctuations in the frequencies of certain chromosomal arrangements, karyotypes and non-Lethal chromosomes under cold-stress temperatures seemed to indicate a correlation between these polymorphisms and environmental conditions. Our results indicate that there is a response in tolerance to extreme temperatures that may be due to natural selection. The differences in mean viability between some O-inversion karyotypic combinations indicate that there are differences in their tolerance to variable temperatures. All our results suggest that both frequency-dependent and supergene selection are mechanisms that protect O-chromosomal inversions. Chromosomal inversions may be genetically differentiated and coadapted complexes in D. subobscura populations.
-
evolution of chilean colonizing populations of drosophila subobscura Lethal Genes and chromosomal arrangements
Genetica, 2009Co-Authors: Francesc Mestres, Joan Balanya, Concepcio Arenas, Marta Pascual, George W Gilchrist, Raymond B Huey, Luis SerraAbstract:Knowledge of the frequency, distribution, and fate of Lethal Genes in chromosomal inversions helps to illuminate the evolution of recently founded populations. We analyze the relationship between Lethal Genes and inversions in two colonizing populations of D. subobscura in Chile. In the ancestral Palearctic populations of this species, Lethal Genes seem distributed at random on chromosomes. But in colonizing American populations, some Lethal Genes are associated with specific chromosomal arrangements. Some of these associated Lethals were detected only during the first stages of the colonization (O3+4+2), and never thereafter, whereas others have persisted (O3+4+7 and O5). However, most Lethal Genes in American populations have been observed only once: they have arisen by novel mutation and soon disappear. Finally, recombination between different inversions has been observed in America. However, the persistence of Lethal Genes associated with the heterotic inversions O3+4+7 and O5 could indicate that recombination inside these inversions is rare.
-
Lethal allelism in Drosophila subobscura: difficulties in the estimation of certain population parameters
Journal of Zoological Systematics and Evolutionary Research, 2009Co-Authors: Francesc Mestres, L SerraAbstract:Although some mathematical models for estimating basic population parameters by means of Lethal allelism analysis are already available, all of them require a knowledge of the values of p∞, (rate of allelism of independently - arisen Lethal Genes), n (number of loci in the chromosome subject to Lethal mutation) and μ (rate of Lethal mutation per generation per chromosome). The experimental estimate of these values poses a serious problem. The present study aims to quantify the extent to which variation in the experimentally obtained estimates of p∞, n and μ can influence the estimated values of certain important population parameters such as Ne (effective population size), s+F (mean selective disadvantage of heterozygotes plus the inbreeding coefficient of the type FID) and h (average reduction in fitness or heterozygotes carrying a Lethal chromosome), in a colonizing (Gilroy, California) and a Palearctic (Bordils, Spain) population of Drosophila subosbscura. It can be concluded that although the mathematical models are necessarily an oversimplification of the biological reality they aim to describe, they are still useful tools for the comparison of the genetic structure of different populations. Zusammenfassung Die Allelierate von Letalfaktoren bei Drosophila subobscura und die Schwierigkeiten, daraus wicbtige Populations-Parameter zu ermitteln Aus der Analyse von Haufigkeit und Allelierate von Letalfaktoren, konnen eine Reihe von wich-tigen Populations-Parametern abgeleitet werden. Dafur gibt es bereits einige gute mathematische Modelle. Zur Berechnung mus man jedoch folgende Werte kennen: Wahrscheinlichkeit fur Alle-lie bei Neumutationen (p∞), Anzahl der Gene, die zu Letalallelen mutieren konnen in dem gerade analysierten Chromosomenabschnitt (n), und die Letalmutationsrate pro Chromosom pro Generation (μ). Die experimentelle Ermittlung dieser Werte wirft einige Probleme auf. Die hier vorgelegte Arbeit untersucht inwieweit Unterschiede in den Schatzwerten fur p∞, n und μ die aus den Mo-dellen resultierenden Bevolkerungsdaten, wie z. B. die effektive Populationsgrose (Ne), der durchschnittliche Heterozygotennachteil bei gegebenem Inzuchtkoeffizienten FID{S+F) und die durchschnittliche Fitness-Reduktion von Letal-Heterozygoten (h), verandern. Als Beispiel werden Werte aus zwei Populationen von Drosophila subobscura vorgestellt; eine der Populatio-nen (Gilroy/Californien) ist eine neu in den USA kolonisierende Population, die andere (Bordils/Spanien) aus dem palaearktischen Zentrum des Artbereichs. Die Modelle sind sicher eine Vereinfachung der biologischen Realitat, aber die eefundenen Werte gestatten es doch, die geneti-sche Struktur der beiden Populationen zu vergleichen.
-
tracking the origin of the american colonization by drosophila subobscura genetic comparison between eastern and western mediterranean populations
Journal of Zoological Systematics and Evolutionary Research, 2009Co-Authors: Pedro A Arauz, Francesc Mestres, Concepcion Arenas, Cinta Pegueroles, G Tzannidakis, C B Krimbas, L SerraAbstract:Several pieces of evidence indicate a Mediterranean origin of the colonization of America by Drosophila subobscura. To ascertain whether the origin was from the Eastern or the Western Mediterranean region, samples from Barcelona (Spain) and Mt Parnes (Greece) were collected and O chromosomal inversion polymorphism and Lethal Genes were analysed. The frequencies of Lethal chromosomes were 0.244 ± 0.039 in Barcelona and 0.336 ± 0.043 in Mt Parnes, consistent with the expectations for large populations located in the central area of the species distribution. Lethal Genes seem to be distributed at random along the O chromosome in both populations. The intra-populational allelism frequencies of Barcelona and Mt Parnes were 0.016 ± 0.007 and 0.012 ± 0.005 respectively. Thus, the estimates of the effective population size were high in both populations (between 6964 and 13 004 in Barcelona and 11 874 to 26 828 in Mt Parnes). The cases of allelism in Mt Parnes were observed only between individual Lethal Genes, but in Barcelona some concatenated clusters of allelism were detected. This pattern of allelism can be explained by synthetic Lethality, hybrid dysGenesis, the induction of recurrent Lethal mutations by different factors or an effect of microdifferentiation in subpopulations. In both populations, a reduction in fitness in the heterozygotes for Lethal Genes has been detected. Furthermore, the estimates of the migration coefficient (between 0.0085 and 0.0120 in Barcelona, and 0.0057 and 0.0087 in Mt Parnes) confirm the existence of gene flow between Palearctic populations of D. subobscura. Our Lethal Genes and chromosomal inversion results are consistent with a Mediterranean origin of the colonization of America by D. subobscura, but are inconclusive with regard to the identification of the population from which these colonizers came.
Sandra T Cooper - One of the best experts on this subject based on the ideXlab platform.
-
gene discovery informatics toolkit defines candidate Genes for unexplained infertility and prenatal or infantile mortality
npj Genomic Medicine, 2019Co-Authors: Ruebena Dawes, Monkol Lek, Sandra T CooperAbstract:Despite a recent surge in novel gene discovery, genetic causes of prenatal-Lethal phenotypes remain poorly defined. To advance gene discovery in prenatal-Lethal disorders, we created an easy-to-mine database integrating known human phenotypes with inheritance pattern, scores of genetic constraint, and murine and cellular knockout phenotypes—then critically assessed defining features of known prenatal-Lethal Genes, among 3187 OMIM Genes, and relative to 16,009 non-disease Genes. While around one-third (39%) of protein-coding Genes are essential for murine development, we curate only 3% (624) of human protein-coding Genes linked currently to prenatal/infantile Lethal disorders. 75% prenatal-Lethal Genes are linked to developmental Lethality in knockout mice, compared to 54% for all OMIM Genes and 34% among non-disease Genes. Genetic constraint correlates with inheritance pattern (autosomal recessive 90% of recessive Genes show neither missense nor loss-of-function constraint, even for prenatal-Lethal Genes. Detailed ontology mapping for 624 prenatal-Lethal Genes shows marked enrichment among dominant Genes for nuclear proteins with roles in RNA/DNA biology, with recessive Genes enriched in cytoplasmic (mitochondrial) metabolic proteins. We conclude that Genes without genetic constraint should not be excluded as potential novel disease Genes, and especially for recessive conditions (<10% constrained). Prenatal Lethal Genes are 5.9-fold more likely to be associated with a Lethal murine phenotype than non-disease Genes. Cell essential Genes are largely a subset of mouse-Lethal Genes, notably under-represented among known OMIM Genes, and strong candidates for gamete/embryo non-viability. We therefore curate 3435 ‘candidate developmental Lethal’ human Genes: essential for murine development or cellular viability, not yet linked to human disorders, presenting strong candidates for unexplained infertility and prenatal/infantile mortality.
-
Gene discovery informatics toolkit defines candidate Genes for unexplained infertility and prenatal or infantile mortality
Nature Publishing Group, 2019Co-Authors: Ruebena Dawes, Monkol Lek, Sandra T CooperAbstract:Abstract Despite a recent surge in novel gene discovery, genetic causes of prenatal-Lethal phenotypes remain poorly defined. To advance gene discovery in prenatal-Lethal disorders, we created an easy-to-mine database integrating known human phenotypes with inheritance pattern, scores of genetic constraint, and murine and cellular knockout phenotypes—then critically assessed defining features of known prenatal-Lethal Genes, among 3187 OMIM Genes, and relative to 16,009 non-disease Genes. While around one-third (39%) of protein-coding Genes are essential for murine development, we curate only 3% (624) of human protein-coding Genes linked currently to prenatal/infantile Lethal disorders. 75% prenatal-Lethal Genes are linked to developmental Lethality in knockout mice, compared to 54% for all OMIM Genes and 34% among non-disease Genes. Genetic constraint correlates with inheritance pattern (autosomal recessive
Kostas Bourtzis - One of the best experts on this subject based on the ideXlab platform.
-
cryopreservation of the mediterranean fruit fly diptera tephritidae vienna 8 genetic sexing strain no effect on large scale production of high quality sterile males for sit applications
PLOS ONE, 2019Co-Authors: Adly M M Abdalla, Jose S Meza, Kostas Bourtzis, Ulysses Sto Tomas, Carlos CaceresAbstract:: The sterile insect technique (SIT) integrated in area-wide integrated pest management (AW-IPM) programmes is being used for the successful management of the Mediterranean fruit fly Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) which is a horticultural pest of economic importance in tropical and subtropical countries. All programmes with an SIT component are using the VIENNA genetic sexing strains (GSS), mainly the VIENNA 8 GSS, which have been developed by applying classical genetic approaches. The VIENNA 8 GSS carries two selectable markers, the white pupae and the temperature sensitive Lethal Genes, which allows the production and release of only males thus increasing the biological efficiency and cost effectiveness of SIT applications. However, mass rearing may affect quality traits of the GSS, in which case replenishment of the colony with wild flies is recommended, a process which is tedious and time consuming. We previously reported the development of a cryopreservation protocol for the VIENNA 8D53+ strain. In the present study, we report on the evaluation of the cryopreserved strain VIENNA 8D53+/Cryo-228L, reared under semi mass rearing conditions, for production parameters, quality control indices and mating competitiveness of males, in a comparative way with the non-cryopreserved VIENNA 8D53+ strain, against wild type males. The VIENNA 8D53+ and VIENNA 8D53+/Cryo-228L strains were similar for production parameters viz. egg production, pupal production, pupal recovery, and quality control indices like fly emergence, sex ratio and flight ability. Males from both strains were equally competitive with males of the wild type strain in achieving mating with wild type females under field cage conditions. Results are discussed in the context of cryopreservation as a potential backup strategy for refreshing the mass rearing colony with biological material from a cryopreserved stock.
-
comparison of classical and transgenic genetic sexing strains of mediterranean fruit fly diptera tephritidae for application of the sterile insect technique
PLOS ONE, 2018Co-Authors: Jose S Meza, Georgios A Kyritsis, Marc J. B. Vreysen, Kostas Bourtzis, Carlos CaceresAbstract:The development of genetic sexing strains (GSSs) based on classical genetic approaches has revolutionized the application of the sterile insect technique (SIT) against the Mediterranean fruit fly Ceratitis capitata (Wiedemann) (Diptera: Tephritidae). The global use of Mediterranean fruit fly GSS for SIT applications as part of area-wide integrated pest management (AW-IPM) programmes is testimony to their effectiveness. During recent years, transgenic sexing strains (TSSs) have been developed through genetic engineering techniques offering the possibility to produce male-only progeny by introducing female embryonic Lethal Genes and to increase the efficacy to identify released sterile males by means of the expression of fluorescent transgene markers. Here, we present a comparative analysis of two Mediterranean fruit fly strains: the classical GSS VIENNA 8D53-/Toliman and the transgenic FSEL#32. The strains were compared for production efficiency and quality control indices under semi mass-rearing conditions, response to sterilizing irradiation doses, male mating performance in walk-in field cages, and production cost of male-only pupae. The results showed that, the FSEL #32 TSS had a similar fecundity but a higher production of male-only pupae than the VIENNA 8D53-/Toliman GSS. For some of the quality control parameters tested, such as pupal weight and survival under starvation conditions, the FSEL #32 TSS was inferior to the VIENNA 8D53-/Toliman GSS. Both the transgenic and the classical genetic sexing strains have shown acceptable and similar mating competitiveness when compared with wild males for mating with wild females. The cost production for both strains is similar but the FSEL#32 TSS may potentially be more cost effective at higher production levels. The results are discussed in the context of incorporating the transgenic strain for SIT application.