The Experts below are selected from a list of 53604 Experts worldwide ranked by ideXlab platform
L Serra - One of the best experts on this subject based on the ideXlab platform.
-
tracking the origin of an invasive species drosophila subobscura in argentina
Journal of Evolutionary Biology, 2009Co-Authors: P Fernandez J Iriarte, Joan Balanya, Francesc Mestres, Marta Pascual, Esteban Hasson, Antonio Fontdevila, L SerraAbstract:Biological invasions are excellent opportunities to study the evolutionary forces leading to the adaptation of a species to a new habitat. Knowledge of the introduction history of colonizing species helps tracking colonizing routes and assists in defining management strategies for invasive species. The Palearctic species Drosophila subobscura is a good model organism for tracking colonizations since it was detected in Chile and western North America three decades ago and later on in the Atlantic coast of Argentina. To unravel the origin of the Argentinean colonizers two populations have been analysed with several Genetic markers. Chromosomal arrangements and microsatellite alleles found in Argentina are almost similar to those observed in Chile and USA. The Lethal allelism test demonstrates that the Lethal Gene associated with the O5 inversions in Argentina is identical to that found in Chile and USA, strongly supporting the hypothesis that all the American colonizing populations originated from the same colonization event. A secondary bottleneck is detected in the Argentinean populations and the Genetic markers suggest that these populations originated from the invasion of 80–150 founding individuals from Chile.
-
chromosomal structure and recombination between inversions in drosophila subobscura
Hereditas, 2004Co-Authors: Francesc Mestres, J Sanz, L SerraAbstract:Drosophila subobscura is a species with rich chromosomal polymorphism. More than 45 arrangements have been described in the 0 chromosome. The recombination between them is an interesting topic, because many nonoverlapping arrangements are inherited together. In the analysis of recombination between the arrangements 0, and 0, + + 8, out of 415 individuals observed none was found to be recombinant. The same result was obtained in the study of the recombination between the inversions 0, and 0, + in which 437 individuals were analyzed. In this case a significant non equivalent segregation was found, the 0, chromosomes being more frequent than expected. This phenomenon could be explained by three hypotheses: a meiotic drive, a greater fitness of the individuals carrying this inversion and heterotic effect of a wild chromosome in combination with a chromosome from an inbred laboratory strain. If the second hypothesis is correct, it could explain why an inversion always associated with a Lethal Gene in American populations is not infrequent and presents a clinal distribution in the colonized areas. Furthermore, another inversion, O,,, is very similar to 05. These two inversions can be distinguished only by careful observation. Although Ozz and 0, are very similar they show different behavior in the wild, probably due to the combinations of Genes included in them.
-
colonization of america by drosophila subobscura heterotic effect of chromosomal arrangements revealed by the persistence of Lethal Genes
Proceedings of the National Academy of Sciences of the United States of America, 2001Co-Authors: Francesc Mestres, Joan Balanya, E Sole, Concepcion Arenas, L SerraAbstract:About 20 years ago Drosophila subobscura, a native Palearctic species, colonized both North and South America. In Palearctic populations Lethal Genes are not associated in General with particular chromosomal arrangements. In colonizing populations they are not randomly distributed and usually are associated to a different degree with chromosomal arrangements caused by the founder event. The persistence of two Lethal Genes in the colonizing populations, one completely associated with the O5 inversion and the other partially associated with the O3+4+7 arrangement, has been analyzed. In all populations studied (five North American and six South American) the observed frequency of the Lethal Gene completely associated with the O5 inversion is higher than expected, the difference being statistically significant in all South American and one North American populations. The observed frequency of the Lethal Gene partially associated with the O3+4+7 arrangement is also significantly higher than expected. Taking into account that the O5 inversion exhibits significant latitudinal clines both in North and South America, an overdominant model favoring the heterokaryotypes seems to be in operation. From this model, a polynomial expression has been developed that allows us to estimate the relative fitness and the coefficient of selection against all karyotypes not carrying the O5 inversion. The relative fitness of the O5 heterokaryotypes is higher in South American than in North American populations. Furthermore, the observed frequencies of the Lethal Genes studied are in General very close to those of the equilibrium. This case is an outstanding demonstration in nature of an heterotic effect of chromosomal segments associated with Lethal Genes on a large geographic scale.
-
colonization of america by drosophila subobscura spatial and temporal Lethal Gene allelism
Hereditas, 2000Co-Authors: E Sole, Joan Balanya, Francesc Mestres, Concepcion Arenas, L SerraAbstract:About twenty years ago Drosophila subobscura, a western Palearctic species, colonized both North and South America. Lethal Genes in the O chromosome has been subject to much research. Lethal Gene allelisms between American populations far away have been studied. These allelisms were not negligible, but all cases were due to the Lethal Gene completely associated to the O5 chromosomal inversion. Here we analyze the Lethal Genes in a new American population of D. subobscura (Centralia, Washington), located fairly close to a previously studied population (Bellingham, Washington) and separated in space and time with other American populations (Gilroy I and II in California and Santiago de Chile). The frequencies of Lethal and semiLethal Genes of Centralia were 16.9+/-4.6 and 6.2+/-3.0, respectively. The intrapopulational allelism of Centralia was 0.122+/-0.036. Interpopulational allelisms were studied using the Lethal Genes from the populations separated in space and time from Centralia. The interpopulational allelisms between Centralia and Gilroy I (California) and between Centralia and Bellingham (Washington) were higher than the intrapopulational allelism (0.155+/-0.032 and 0.153+/-0.024, respectively). In all these cases allelism was due to a complete association between a Lethal Gene and the O5 chromosomal inversion. Accordingly, no other Lethal Genes are shared in these populations.
-
colonization of the americas by drosophila subobscura Lethal Gene allelism and association with chromosomal arrangements
Genetics, 1995Co-Authors: Francesc Mestres, L Serra, Francisco J AyalaAbstract:Drosophila subobscura is a Palearctic species that has recently colonized the Americas. It was first found in 1978 in Puerto Montt, Chile, and in 1982 in Port Townsend, WA. The colonization and rapid expansion of the species in western South and North America provides distinctive opportunities for investigating the process of evolution in action. The inversion polymorphism in the O chromosome from populations of central California and northern Washington, separated by 1300 km, corresponds to a previously observed latitudinal cline, also observed in Europe. Recessive Lethal Genes are not randomly distributed among the chromosomal arrangements. The incidence of Lethal allelism is high, yielding unrealistically low estimates of the effective size of these populations (on the order of 1000 individuals). The high incidence of Lethal allelism is likely to be a consequence of the low number of the American colonizers (on the order of 10-100 individuals), but the persistence of the allelism over several years suggests that some Lethal-carrying chromosomes may be heterotic owing to shared associations between Lethal and other Genes.
Francesc Mestres - One of the best experts on this subject based on the ideXlab platform.
-
tracking the origin of an invasive species drosophila subobscura in argentina
Journal of Evolutionary Biology, 2009Co-Authors: P Fernandez J Iriarte, Joan Balanya, Francesc Mestres, Marta Pascual, Esteban Hasson, Antonio Fontdevila, L SerraAbstract:Biological invasions are excellent opportunities to study the evolutionary forces leading to the adaptation of a species to a new habitat. Knowledge of the introduction history of colonizing species helps tracking colonizing routes and assists in defining management strategies for invasive species. The Palearctic species Drosophila subobscura is a good model organism for tracking colonizations since it was detected in Chile and western North America three decades ago and later on in the Atlantic coast of Argentina. To unravel the origin of the Argentinean colonizers two populations have been analysed with several Genetic markers. Chromosomal arrangements and microsatellite alleles found in Argentina are almost similar to those observed in Chile and USA. The Lethal allelism test demonstrates that the Lethal Gene associated with the O5 inversions in Argentina is identical to that found in Chile and USA, strongly supporting the hypothesis that all the American colonizing populations originated from the same colonization event. A secondary bottleneck is detected in the Argentinean populations and the Genetic markers suggest that these populations originated from the invasion of 80–150 founding individuals from Chile.
-
chromosomal structure and recombination between inversions in drosophila subobscura
Hereditas, 2004Co-Authors: Francesc Mestres, J Sanz, L SerraAbstract:Drosophila subobscura is a species with rich chromosomal polymorphism. More than 45 arrangements have been described in the 0 chromosome. The recombination between them is an interesting topic, because many nonoverlapping arrangements are inherited together. In the analysis of recombination between the arrangements 0, and 0, + + 8, out of 415 individuals observed none was found to be recombinant. The same result was obtained in the study of the recombination between the inversions 0, and 0, + in which 437 individuals were analyzed. In this case a significant non equivalent segregation was found, the 0, chromosomes being more frequent than expected. This phenomenon could be explained by three hypotheses: a meiotic drive, a greater fitness of the individuals carrying this inversion and heterotic effect of a wild chromosome in combination with a chromosome from an inbred laboratory strain. If the second hypothesis is correct, it could explain why an inversion always associated with a Lethal Gene in American populations is not infrequent and presents a clinal distribution in the colonized areas. Furthermore, another inversion, O,,, is very similar to 05. These two inversions can be distinguished only by careful observation. Although Ozz and 0, are very similar they show different behavior in the wild, probably due to the combinations of Genes included in them.
-
colonization of america by drosophila subobscura heterotic effect of chromosomal arrangements revealed by the persistence of Lethal Genes
Proceedings of the National Academy of Sciences of the United States of America, 2001Co-Authors: Francesc Mestres, Joan Balanya, E Sole, Concepcion Arenas, L SerraAbstract:About 20 years ago Drosophila subobscura, a native Palearctic species, colonized both North and South America. In Palearctic populations Lethal Genes are not associated in General with particular chromosomal arrangements. In colonizing populations they are not randomly distributed and usually are associated to a different degree with chromosomal arrangements caused by the founder event. The persistence of two Lethal Genes in the colonizing populations, one completely associated with the O5 inversion and the other partially associated with the O3+4+7 arrangement, has been analyzed. In all populations studied (five North American and six South American) the observed frequency of the Lethal Gene completely associated with the O5 inversion is higher than expected, the difference being statistically significant in all South American and one North American populations. The observed frequency of the Lethal Gene partially associated with the O3+4+7 arrangement is also significantly higher than expected. Taking into account that the O5 inversion exhibits significant latitudinal clines both in North and South America, an overdominant model favoring the heterokaryotypes seems to be in operation. From this model, a polynomial expression has been developed that allows us to estimate the relative fitness and the coefficient of selection against all karyotypes not carrying the O5 inversion. The relative fitness of the O5 heterokaryotypes is higher in South American than in North American populations. Furthermore, the observed frequencies of the Lethal Genes studied are in General very close to those of the equilibrium. This case is an outstanding demonstration in nature of an heterotic effect of chromosomal segments associated with Lethal Genes on a large geographic scale.
-
colonization of america by drosophila subobscura spatial and temporal Lethal Gene allelism
Hereditas, 2000Co-Authors: E Sole, Joan Balanya, Francesc Mestres, Concepcion Arenas, L SerraAbstract:About twenty years ago Drosophila subobscura, a western Palearctic species, colonized both North and South America. Lethal Genes in the O chromosome has been subject to much research. Lethal Gene allelisms between American populations far away have been studied. These allelisms were not negligible, but all cases were due to the Lethal Gene completely associated to the O5 chromosomal inversion. Here we analyze the Lethal Genes in a new American population of D. subobscura (Centralia, Washington), located fairly close to a previously studied population (Bellingham, Washington) and separated in space and time with other American populations (Gilroy I and II in California and Santiago de Chile). The frequencies of Lethal and semiLethal Genes of Centralia were 16.9+/-4.6 and 6.2+/-3.0, respectively. The intrapopulational allelism of Centralia was 0.122+/-0.036. Interpopulational allelisms were studied using the Lethal Genes from the populations separated in space and time from Centralia. The interpopulational allelisms between Centralia and Gilroy I (California) and between Centralia and Bellingham (Washington) were higher than the intrapopulational allelism (0.155+/-0.032 and 0.153+/-0.024, respectively). In all these cases allelism was due to a complete association between a Lethal Gene and the O5 chromosomal inversion. Accordingly, no other Lethal Genes are shared in these populations.
-
colonization of the americas by drosophila subobscura Lethal Gene allelism and association with chromosomal arrangements
Genetics, 1995Co-Authors: Francesc Mestres, L Serra, Francisco J AyalaAbstract:Drosophila subobscura is a Palearctic species that has recently colonized the Americas. It was first found in 1978 in Puerto Montt, Chile, and in 1982 in Port Townsend, WA. The colonization and rapid expansion of the species in western South and North America provides distinctive opportunities for investigating the process of evolution in action. The inversion polymorphism in the O chromosome from populations of central California and northern Washington, separated by 1300 km, corresponds to a previously observed latitudinal cline, also observed in Europe. Recessive Lethal Genes are not randomly distributed among the chromosomal arrangements. The incidence of Lethal allelism is high, yielding unrealistically low estimates of the effective size of these populations (on the order of 1000 individuals). The high incidence of Lethal allelism is likely to be a consequence of the low number of the American colonizers (on the order of 10-100 individuals), but the persistence of the allelism over several years suggests that some Lethal-carrying chromosomes may be heterotic owing to shared associations between Lethal and other Genes.
James J Bull - One of the best experts on this subject based on the ideXlab platform.
-
Lethal Gene drive selects inbreeding
Evolution Medicine and Public Health, 2016Co-Authors: James J BullAbstract:The use of 'selfish' Gene drive systems to suppress or even extinguish populations has been proposed on theoretical grounds for almost half a century. Creating these Genes has recently become possible with CRISPR technology. One seemingly feasible approach, originally proposed by Burt, is to create a homing endonuclease Gene (HEG) that inserts into an essential Gene, enabling heterozygote viability but causing homozygote Lethality. With 100% segregation distortion in gametes, such Genes can cause profound population suppression if resistance does not evolve. Here, population Genetic models are used to consider the evolution of inbreeding (specifically selfing) as a possible response to a recessively Lethal HEG with complete segregation distortion. Numerical analyses indicate a rich set of outcomes, but selfing often evolves in response to the HEG, with a corresponding partial restoration of mean fitness. Whether selfing does indeed evolve and its effect in restoring fitness depends heavily on the magnitude of inbreeding depression. Overall, these results point toward an underappreciated evolutionary response to block the harmful effects of a selfish Gene. They raise the possibility that extreme population suppression may be resisted by mechanisms that are independent of the molecular basis of Gene drive. At the same time, the evolution of inbreeding is not assured even if the Genetic basis for inbreeding is present. As the models here strictly apply to hermaphrodites (plants), an important next step is to consider inbreeding in populations with separate sexes.
-
Lethal Gene drive selects inbreeding
bioRxiv, 2016Co-Authors: James J BullAbstract:The use of 'selfish' Gene drive systems to suppress or even extinguish populations has been proposed on theoretical grounds for almost half a century. Creating these Genes has recently become possible with CRISPR technology. One seemingly feasible approach, originally proposed by Burt, is to create a homing endonuclease Gene (HEG) that inserts into an essential Gene, enabling heterozygote viability but causing homozygote Lethality. With 100\% segregation distortion in gametes, such Genes can cause profound population suppression if resistance does not evolve. Here, population Genetic models are used to consider the evolution of inbreeding (specifically selfing) as a possible response to a recessively Lethal HEG with complete segregation distortion. Numerical analyses indicate a rich set of outcomes, but selfing often evolves in response to the HEG, with a corresponding partial restoration of mean fitness. Whether selfing does indeed evolve and its effect in restoring fitness depends heavily on the magnitude of inbreeding depression. Overall, these results point toward an underappreciated evolutionary response to block the harmful effects of a selfish Gene. They raise the possibility that extreme population suppression may be more difficult to achieve than currently imagined.
-
Lethal Gene drive selects escape through inbreeding
bioRxiv, 2016Co-Authors: James J BullAbstract:The use of 'selfish' Gene drive systems to suppress or even extinguish populations has been proposed on theoretical grounds for almost half a century. Creating these Genes has recently become possible with CRISPR technology. One seemingly feasible approach, originally proposed by Burt, is to create a homing endonuclease Gene (HEG) that inserts into an essential Gene, enabling heterozygote viability but causing homozygote Lethality. With 100\% segregation distortion in gametes, such Genes can cause profound population suppression if resistance does not evolve. Here, population Genetic models are used to consider the evolution of inbreeding (selfing) as a possible response to a recessively Lethal HEG with complete segregation distortion. Numerical results indicate a rich set of outcomes, but selfing often evolves in response to the HEG. Whether selfing does indeed evolve and its effect in restoring population fitness depends heavily on the magnitude of inbreeding depression. Overall, these results point toward an underappreciated evolutionary response to block the harmful effects of a selfish Gene. They raise the possibility that extreme population suppression may be more difficult to achieve than currently imagined.
Benno Mullerhill - One of the best experts on this subject based on the ideXlab platform.
-
a positive selection vector for cloning of long polymerase chain reaction fragments based on a Lethal mutant of thecrpGene ofescherichia coli
Analytical Biochemistry, 1998Co-Authors: Daniel Schlieper, Harald Sobek, Brigitte Von Wilckenbergmann, Manfred Schmidt, Benno MullerhillAbstract:Abstract We have constructed a cloning vector with a tight positive selection for recombinant clones inEscherichia coli.The positive selection pressure results from a Lethal mutation within theE. coliGene coding for the catabolite Gene activator protein CAP, which is disrupted whenever a fragment is successfully inserted. Here, we show that this “suicide” vector, pCAPs, is suitable for cloning of PCR products as long as 9.3 kb into several unique restriction sites which are scattered throughout the Lethal Gene.
Nyadar Palmah M. - One of the best experts on this subject based on the ideXlab platform.
-
A small molecule for a big transformation: Topical application of a 20-nucleotide-long antisense fragment of the DIAP-2 Gene inhibits the development of Drosophila melanogaster female imagos
University of Belgrade University of Novi Sad, 2018Co-Authors: Nyadar Palmah M., Oberemok Volodymyr, Zubarev IlyaAbstract:Several Genes have been identified to play important roles associated with sex selection in Drosophila melanogaster. An essential part is attributed to the sex-Lethal Gene that depends on the expression of the X:A (number of chromosomes to autosomes) ratio signal controlling both sex selection and dosage compensation processes in D. melanogaster. Interestingly, for sex selection in D. melanogaster there are no documented data addressing the role of the inhibitor of apoptosis (IAP) Genes and their signaling influence on this biological process. In this study, we found that topical application of a 20-nucleotide-long antisense DNA fragment (oligoDIAP-2) from the death-associated inhibitor of apoptosis (DIAP)-2 Gene interferes with D. melanogaster development and significantly decreases the number of female imagos and their biomass. We show that the applied antisense oligoDIAP-2 fragment downregulates the target DIAP-2 Gene whose normal concentration is necessary for the development of female D. melanogaster. These data correspond to the results on downregulation of the target host IAP-Z Gene of Lymantria dispar L. female imagos after topical treatment with an 18-nucleotide-long antisense DNA fragment from the L. dispar multicapsid nuclear polyhedrosis virus IAP-3 Gene at the larval stage. The observed novel phenomenon linking the downregulation of insect IAP Genes and the low rate of female imago development could have practical application, especially in insect pest control and molecular pathology
-
A small molecule for a big transformation: Topical application of a 20-nucleotidelong antisense fragment of the DIAP-2 Gene inhibits the development of Drosophila melanogaster female imagos
'National Library of Serbia', 2018Co-Authors: Nyadar Palmah M., Oberemok V., Zubarev I.Abstract:Several Genes have been identified to play important roles associated with sex selection in Drosophila melanogaster. An essential part is attributed to the sex-Lethal Gene that depends on the expression of the X:A (number of chromosomes to autosomes) ratio signal controlling both sex selection and dosage compensation processes in D. melanogaster. Interestingly, for sex selection in D. melanogaster there are no documented data addressing the role of the inhibitor of apoptosis (IAP) Genes and their signaling influence on this biological process. In this study, we found that topical application of a 20-nucleotide-long antisense DNA fragment (oligoDIAP-2) from the death-associated inhibitor of apoptosis (DIAP)-2 Gene interferes with D. melanogaster development and significantly decreases the number of female imagos and their biomass. We show that the applied antisense oligoDIAP-2 fragment downregulates the target DIAP-2 Gene whose normal concentration is necessary for the development of female D. melanogaster. These data correspond to the results on downregulation of the target host IAP-Z Gene of Lymantria dispar L. female imagos after topical treatment with an 18-nucleotide-long antisense DNA fragment from the L. dispar multicapsid nuclear polyhedrosis virus IAP-3 Gene at the larval stage. The observed novel phenomenon linking the downregulation of insect IAP Genes and the low rate of female imago development could have practical application, especially in insect pest control and molecular pathology. © 2018 by the Serbian Biological Society