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Significant Genetic Differences (significant + genetic_difference)
Selected AbstractsGenetic diversity in pollen beetles (Meligethes aeneus) in Sweden: role of spatial, temporal and insecticide resistance factorsAGRICULTURAL AND FOREST ENTOMOLOGY, Issue 4 2007Nadiya Kazachkova Abstract 1,Pollen beetles Meligethes aeneus are pests of oilseed Brassica crops that are subject to intensive chemical control. Resistance to pyrethroids has been reported. Although this insect is of great economic importance, little is known about its genetic properties and population structure. 2,Amplified fragment length polymorphism (AFLP) analysis with the restriction endonuclease combination EcoRI and PstI was performed on 133 samples of groups of three pollen beetles collected during 2001,04 from five different provinces of Sweden. Both susceptible and resistant insects were studied. Using one primer combination, more than 450 polymorphic DNA fragments were obtained and, in total, four primer combinations were used for analysis. A subsample of 59 single beetles was analysed using one primer combination. 3,AFLP profiles were analysed by similarity measures using the Nei and Li coefficient and Neighbour-joining dendrograms were generated. The dendrogram built using 133 samples showed three distinct groups, each containing beetles representing one generation. Statistical analysis using analysis of molecular variance of single beetle samples showed no evidence of significant genetic difference between resistant and susceptible beetles. Instead, a clear difference between samples, depending on time of collection and generation, was observed. 4,The expected regional population structure, although statistically significant, explained little of the variation. The levels of genetic variation within populations were very high. There appears to be a high rate of gene flow between pollen beetle populations. The implications of this in the context of insecticide resistance are discussed. [source] Genetic diversity measures of the bovine Alberes breed using microsatellites: variability among herds and types of coat colour,JOURNAL OF ANIMAL BREEDING AND GENETICS, Issue 2 2004J. Casellas Summary The Alberes population is a native bovine breed of Catalonia with an unclear origin, which historically some authors have assumed as being composed of two different colour varieties (black and fawn). Sixteen microsatellite loci were analysed, all of them included in the AIRE2066 European Concerted Action list. Overall expected and observed heterozygosities reached values of 0.649 and 0.662, respectively. Genetic differences among black and fawn varieties were not significant (FST = 0.007), and therefore the population is a single variety with a great colour gradation. On the contrary, we detected significant genetic differences among herds (FST = 0.026; p < 0.001), showing a genetic heterogeneity over short geographical distances. The number of migrants per generation among pairs of herds oscillates between 1.46 (Roig and Freixe herds) and 5.62 (Castanyers and Roig herds). Moreover, inbreeding and bottleneck situations can be rejected. The Alberes breed has been grouped within the Cantabrian trunk, closely related to the Asturiana de la Montaña and Alistana breeds, although some other breeds may also have influenced the population along its history. Zusammenfassung Die Rasse Alberes ist eine einheimische Rinderrasse Kataloniens mit unklarer Herkunft, von der historisch einige Autoren vermuten, dass sie eine Zusammensetzung aus zwei verschiedenen Farbvarianten ist (schwarz und hellbraun). Es wurden sechzehn Mikrosatelliten, die alle aus der ,,AIRE2066 European Concerted Action list,, stammen, analysiert. Der gesamte erwartete und beobachtete Heterozygotiegrad erreichte Werte von 0,649 beziehungsweise 0,662. Die genetischen Unterschiede zwischen den schwarzen und hellbraunen Varianten waren nicht signifikant (Fst = 0,007), so dass die Rasse als eine einzige Variante mit einer großen Farbabstufung gilt, die wir erhalten müssen. Im Gegensatz dazu entdeckten wir signifikante genetische Unterschiede innerhalb der Herden (Fst = 0,026, p < 0,001), die eine genetische Heterogenität innerhalb kurzer geografischer Distanzen aufzeigten. Die Anzahl an Migranten pro Generation innerhalb der Herdpaare schwankt zwischen 1,46 (Roig - und Freixe -Herden) und 5,62 (Castanyers - und Roig -Herden). Darüberhinaus kann Inzucht und eine Flaschenhalssituation zurückgewiesen werden. Die Rasse Alberes wurde innerhalb eines Cantabrischen Astes gruppiert, in enger Verwandtschaft zu den Rassen Asturiana de la Montaña und Alistana, obwohl im Laufe der Geschichte auch einige andere Rassen die Population beeinflusst haben könnten. [source] DNA analysis of transferred sperm reveals significant levels of gene flow between molecular forms of Anopheles gambiaeMOLECULAR ECOLOGY, Issue 7 2001F. Tripet Abstract Anopheles gambiae populations in west Africa are complex, being composed of multiple, sympatric subpopulations. Recent studies have failed to reveal significant genetic differences among subpopulations, stimulating a debate regarding the levels of gene flow among them. The observed homogeneity may be the consequence of substantial contemporary gene flow or it may be that reproductive isolation is complete, but too recent for the accumulation of significant levels of genic divergence. Here, we report the results of a study estimating contemporary levels of gene flow between An. gambiae subpopulations by analysing females and transferred sperm removed from their reproductive systems. A total of 251 female and associated sperm extracts was analysed from a single site in Mali. Two molecular forms of An. gambiae, the M- and S-forms, occurred in sympatry at this site. Overall, we found very strong positive assortative mating within forms, however, we did observe significant hybridization between forms. In the M subpopulation 2/195 females (1.03%) contained sperm from S-form males and in 55 S-form females we found one female containing M-form sperm (1.82%). We also identified a mated M ×S hybrid adult female. From mating frequencies, we estimate the Nem between the M- and S-form at 16.8, and from the adult hybrid frequency at 5.6. These values are consistent with our earlier estimate, based on FST for 21 microsatellite loci in which Nem = 5.8. We conclude that the general lack of genetic divergence between the M and S subpopulations of An. gambiae can be explained entirely by contemporary gene flow. [source] Study of GM immunoglobulin allotypic system in Berbers and Arabs from MoroccoAMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 1 2006C. Coudray The GM immunoglobulin allotype polymorphism was investigated in four Moroccan populations: three Berber groups from Khenifra (Middle Atlas), Amizmiz (High Atlas), and Bouhria (Beni Snassen) and one Arabic-speaking sample from the Doukkala area (Abda, Chaouia, Doukkali, and Tadla districts in south-central Morocco). In order to characterize the genetic relationships between the populations, our results were compared with those obtained for other North African groups (from Morocco, Algeria, Tunisia, and Niger) and for Middle-East Africans, sub-Saharans, and Southwest Europeans. Based on GM haplotype frequencies, Factorial Correspondence Analyses, FST significance testing, and hierarchical analyses of variance were performed. Our results reveal that Moroccan populations have heterogeneous GM profiles with high frequencies of GM haplotypes in Europeans (from 76% for Doukkala to 88% for Bouhria) and relatively high frequencies of GM haplotypes in sub-Saharans (from 11% for Bouhria to 23% for Amizmiz). The genetic diversity observed among Moroccans is not significantly correlated with either geographic or linguistic differentiation. In spite of their cultural and historical differentiation, we did not discover any significant genetic differences between Berbers and Arabic-speakers from Morocco. However, when large geographical areas are considered, our population samples are integrated in the North African GM variation, significantly distant from sub-Saharan groups but with a close relationship with Southwest European populations. Am. J. Hum. Biol. 18:23,34, 2006. © 2005 Wiley-Liss, Inc. [source] Genetic diversity in German draught horse breeds compared with a group of primitive, riding and wild horses by means of microsatellite DNA markersANIMAL GENETICS, Issue 4 2004K. S. Aberle Summary We compared the genetic diversity and distance among six German draught horse breeds to wild (Przewalski's Horse), primitive (Icelandic Horse, Sorraia Horse, Exmoor Pony) or riding horse breeds (Hanoverian Warmblood, Arabian) by means of genotypic information from 30 microsatellite loci. The draught horse breeds included the South German Coldblood, Rhenish German Draught Horse, Mecklenburg Coldblood, Saxon Thuringa Coldblood, Black Forest Horse and Schleswig Draught Horse. Despite large differences in population sizes, the average observed heterozygosity (Ho) differed little among the heavy horse breeds (0.64,0.71), but was considerably lower than in the Hanoverian Warmblood or Icelandic Horse population. The mean number of alleles (NA) decreased more markedly with declining population sizes of German draught horse breeds (5.2,6.3) but did not reach the values of Hanoverian Warmblood (NA = 6.7). The coefficient of differentiation among the heavy horse breeds showed 11.6% of the diversity between the heavy horse breeds, as opposed to 21.2% between the other horse populations. The differentiation test revealed highly significant genetic differences among all draught horse breeds except the Mecklenburg and Saxon Thuringa Coldbloods. The Schleswig Draught Horse was the most distinct draught horse breed. In conclusion, the study demonstrated a clear distinction among the German draught horse breeds and even among breeds with a very short history of divergence like Rhenish German Draught Horse and its East German subpopulations Mecklenburg and Saxon Thuringa Coldblood. [source] | ||||||||||