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Genetic Homogeneity (genetic + homogeneity)
Selected AbstractsGenetic characterization of Erwinia amylovora strains by amplified fragment length polymorphismJOURNAL OF APPLIED MICROBIOLOGY, Issue 2 2004A. Rico Abstract Aims:,Erwinia amylovora is one of the most important pathogens of pear and apple and is subject to strict quarantine regulations worldwide, although its patterns of dispersal are largely unknown. Previous attempts to fingerprint E. amylovora strains by molecular techniques have detected very little polymorphism because of the high genetic homogeneity of this bacterium. Our aim was to establish and test a typing method to quantify genetic diversity among strains of this plant pathogen. Methods and Results:, Twenty-two strains from different hosts and geographical locations were examined by PCR fingerprinting with four primers and by amplified fragment length polymorphism (AFLP) with four selected combinations of primers with a single base extension. PCR fingerprinting revealed little polymorphism producing the same amplification patterns for 17 strains, while the combined AFLP patterns yielded 78 polymorphic bands (34% of total bands) and allowed the differentiation of all but two strains. Clustering of strains in the resulting dendrogram was not correlated with host, year or country of isolation, and questions previous genealogies based on PFGE patterns. Conclusions:, The AFLP technique allowed the detection of an unprecedented number of genetic markers in E. amylovora and proved to be the most useful tool so far for discriminating among strains of this pathogen. The results obtained in this study strongly suggest the occurrence of multiple introductions of the pathogen in Spain and other European countries. Significance and Impact of the Study:, A major limitation in understanding the ecology of fire blight is the lack of typing techniques with a high power of discrimination. This study demonstrates the high resolution and the usefulness of the AFLP technique to differentiate among E. amylovora strains. [source] Genetic analysis of offspring from intra- and interspecific crosses of Carassius auratus gibelio by chromosome and RAPD analysisJOURNAL OF FISH BIOLOGY, Issue 3 2005B. Tóth The ploidy of silver crucian carp Carassius auratus gibelio individuals, originating from nine natural habitats of Hungary, was estimated by erythrocyte nucleus area analysis. On the basis of DNA polymorphism, the genetic homogeneity or heterogeneity and the chromosome number of different offspring derived from the crossing of triploid and diploid populations and of two types of silver crucian carp females with other cyprinid males (Cyprinus carpio, Carassius carassius, Carassius auratus and Barbus conchonius) were determined. The results of chromosome and RAPD analysis demonstrated that diploid females could reproduce sexually with silver crucian carp and other cyprinid males and that the offspring of intra- and interspecific crosses contained the paternal DNA. Triploid females usually reproduced by gynogenesis and their offspring were clones, however, in very rare cases paternal genes were actually transmitted (i.e. paternal leakage) to the offspring and the progeny were triploid interspecific hybrids. RAPD analysis showed that while the paternal DNA appeared in the offspring, the maternal phenotype was strongly expressed. [source] Molecular characterization of the fish-pathogenic fungus Aphanomyces invadansJOURNAL OF FISH DISEASES, Issue 5 2003J H Lilley Abstract Aphanomyces invadans (Saprolegniaceae) is a peronosporomycete fungus associated with the serious fish disease, epizootic ulcerative syndrome (EUS), also known as mycotic granulomatosis. In this study, interspecific relationships were examined between A. invadans isolates and other aquatic animal pathogenic Saprolegniaceae, and saprophytic Saprolegniaceae from EUS-affected areas. Restriction fragment length polymorphisms and sequences of ribosomal DNA confirmed that A. invadans is distinct from all other species studied. A sequence from the internal transcribed spacer region ITS1, unique to A. invadans, was used to design primers for a PCR-based diagnostic test. Intraspecific relationships were also examined by random amplification of polymorphic DNA using 20 isolates of A. invadans from six countries. The isolates showed a high degree of genetic homogeneity using 14 random ten-mer primers. This provides evidence that the fungus has spread across Asia in one relatively rapid episode, which is consistent with reports of outbreaks of EUS. Physiological distinctions between A. invadans and other Aphanomyces species based on a data set of 16 growth parameters showed remarkable taxonomic congruence with the molecular phylogeny. [source] N-MYC Downstream-Regulated Gene 1 Is Mutated In Hereditary Motor And Sensory Neuropathy-LOMJOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 1 2001L Kalaydjieva Hereditary motor and sensory neuropathies, to which Charcot-Marie-Tooth (CMT) disease belongs, are a common cause of disability in adulthood. Growing awareness that axonal loss, rather than demyelination per se, is responsible for the neurological deficit in demyelinating CMT disease has focused research on the mechanisms of early development, cell differentiation, and cell-cell interactions in the peripheral nervous system. Autosomal recessive peripheral neuropathies are relatively rare but are clinically more severe than autosomal dominant forms of CMT, and understanding their molecular basis may provide a new perspective on these mechanisms. Here we report the identification of the gene responsible for hereditary motor and sensory neuropathy-Lom (HMSNL). HMSNL shows features of Schwann-cell dysfunction and a concomitant early axonal involvement, suggesting that impaired axon-glia interactions play a major role in its pathogenesis. The gene was previously mapped to 8q24.3, where conserved disease haplotypes suggested genetic homogeneity and a single founder mutation. We have reduced the HMSNL interval to 200 kb and have characterized it by means of large-scale genomic sequencing. Sequence analysis of two genes located in the critical region identified the founder HMSNL mutation: a premature-termination codon at position 148 of the N-myc downstream-regulated gene 1 (NDRG1). NDRG1 is ubiquitously expressed and has been proposed to play a role in growth arrest and cell differentiation, possibly as a signaling protein shuttling between the cytoplasm and the nucleus. We have studied expression in peripheral nerve and have detected particularly high levels in the Schwann cell. Taken together, these findings point to NDRG1 having a role in the peripheral nervous system, possibly in the Schwann-cell signaling necessary for axonal survival. [source] Conflicting estimates of connectivity among deep-sea coral populationsMARINE ECOLOGY, Issue 2010Karen Miller Abstract Genetic data were used as an indirect means of assessing connectivity among deep-sea coral populations on seamounts and slopes in the Australian and New Zealand region. We sequenced three DNA regions (16S, ITS and Control Region) in nine deep-sea coral species from sites spanning thousands of kilometers. Based on haplotype distributions and AMOVA, we found evidence of genetic subdivision across ocean expanses for three species: the scleractinian Desmophyllum dianthus, and the antipatharians Antipathes robillardi and Stichopathes variabilis. Levels of genetic variation were low for the remaining species, including the reef-forming Solenosmila variablis and Madrepora oculata, and more sensitive molecular markers may be needed to resolve their spatial structure properly. For two species (the scleractinian Stephanocyathus spiniger and the antipatharian Stichopathes filiformis), we found no evidence of genetic subdivision among sites within regions, suggesting sufficient gene flow occurs to maintain genetic homogeneity at scales of tens to hundreds of kilometers. Recognising that some seamount regions and coral populations are, or are not, effectively isolated will be a key component of successful management planning based on marine protected area networks , both within and beyond national jurisdictions. [source] High gene flow promotes the genetic homogeneity of the fish goby Pomatoschistus marmoratus (Risso, 1810) from Mar Menor coastal lagoon and adjacent marine waters (Spain)MARINE ECOLOGY, Issue 2 2010Carlos Vergara-Chen Abstract The extreme environmental variability of coastal lagoons suggests that physical and ecological factors could contribute to the genetic divergence among populations occurring in lagoon and open-coast environments. In this study we analysed the genetic variability of lagoon and marine samples of the sand goby, Pomatoschistus marmoratus (Risso, 1810) (Pisces: Gobiidae), on the SW Spain coast. A fragment of mitochondrial DNA control region (570 bp) was sequenced for 196 individuals collected in five localities: Lo Pagan, Los Urrutias and Playa Honda (Mar Menor coastal lagoon), and Veneziola and Mazarrón (Mediterranean Sea). The total haplotype diversity was h = 0.9424 ± 0.0229, and the total nucleotide diversity was , = 0.0108 ± 0.0058. Among-sample genetic differentiation was not significant and small-scale patterns in the distribution of haplotypes were not apparent. Gene flow and dispersal-related life history traits may account for low genetic structure at a small spatial scale. The high genetic diversity found in P. marmoratus increases its potential to adapt to changing conditions of the Mar Menor coastal lagoon. [source] Streptococcus suis outbreak investigation using multiple-locus variable tandem repeat number analysisMICROBIOLOGY AND IMMUNOLOGY, Issue 7 2010Wei Li ABSTRACT Two outbreaks of Streptococcus suis ST7 occurred in humans in 1998 and 2005 in China. PFGE of chromosome restriction fragments found all ST7 isolates to be indistinguishable. Due to the genetic homogeneity of ST7 isolates, development of a rapid sub-typing method with high discriminatory power for ST7 isolates is required. In this study, a novel method, MLVA, was developed to type S. suis serotype 2 strains. Further, this method was used to analyze outbreak-associated ST7 strains in China. A total of 144 ST7 S. suis isolates were sub-typed into 34 MLVA types. Among these, eight isolates from the 1998 outbreak were sub-typed into five MLVA types, of which four MLVA types were also detected in Sichuan in 2005. These data indicate that the pathogens responsible for the two outbreaks had the same origin. In addition, some observations also provided molecular evidence for the transmission route, possibly indicating that the MLVA method has usefulness in epidemiology. The developed MLVA scheme for S. suis has greater discriminative power than PFGE. The method described here may be useful for identifying the source of S. suis infection and monitoring its spread. [source] Contrasting mtDNA diversity and population structure in a direct-developing marine gastropod and its trematode parasitesMOLECULAR ECOLOGY, Issue 22 2009DEVON B. KEENEY Abstract The comparative genetic structure of hosts and their parasites has important implications for their coevolution, but has been investigated in relatively few systems. In this study, we analysed the genetic structure and diversity of the New Zealand intertidal snail Zeacumantus subcarinatus (n = 330) and two of its trematode parasites, Maritrema novaezealandensis (n = 269) and Philophthalmus sp. (n = 246), using cytochrome c oxidase subunit I gene (COI) sequences. Snails and trematodes were examined from 11 collection sites representing three regions on the South Island of New Zealand. Zeacumantus subcarinatus displayed low genetic diversity per geographic locality, strong genetic structure following an isolation by distance pattern, and low migration rates at the scale of the study. In contrast, M. novaezealandensis possessed high genetic diversity, genetic homogeneity among collection sites and high migration rates. Genetic diversity and migration rates were typically lower for Philophthalmus sp. compared to M. novaezealandensis and it displayed weak to moderate genetic structure. The observed patterns likely result from the limited dispersal ability of the direct developing snail and the utilization of bird definitive hosts by the trematodes. In addition, snails may occasionally experience long-distance dispersal. Discrepancies between trematode species may result from differences in their effective population sizes and/or life history traits. [source] Pleistocene glaciation events shape genetic structure across the range of the American lobster, Homarus americanusMOLECULAR ECOLOGY, Issue 8 2009ELLEN L. KENCHINGTON Abstract A north/south discontinuity along the northeastern coast of North America in the genetic structure of the American lobster (Homarus americanus) was detected using a suite of 13 microsatellite loci assessed using spatial analyses. Population genetic data laid over existing data on physiographic changes and sea-surface temperatures were used to reconstruct the Pleistocene distribution of this species. A postglacial northern-edge colonization model best explains the relative genetic homogeneity of the northern region compared to the southern region centred in the Gulf of Maine. Population genetic analyses identified significant structure (range of standardized theta 0,0.02) but no significant evidence for isolation by distance. The novel application of spatial genetic analyses to a marine species allowed us to interpret these results by providing a greater insight into the evolutionary factors responsible for shaping the genetic structure of this species throughout is natural range. [source] Strain-specific regulation of intracellular Wolbachia density in multiply infected insectsMOLECULAR ECOLOGY, Issue 12 2003L. Mouton Abstract Vertically transmitted symbionts suffer a severe reduction in numbers when they pass through host generations, resulting in genetic homogeneity or even clonality of their populations. Wolbachia endosymbionts that induce cytoplasmic incompatibility in their hosts depart from this rule, because cytoplasmic incompatibility actively maintains multiple infection within hosts. Hosts and symbionts are thus probably under peculiar selective pressures that must shape the way intracellular bacterial populations are regulated. We studied the density and location of Wolbachia within adult Leptopilina heterotoma, a haplodiploid wasp that is parasitic on Drosophila and that is naturally infected with three Wolbachia strains, but for which we also obtained one simply infected and two doubly infected lines. Comparison of these four lines by quantitative polymerase chain reaction using a real-time detection system showed that total Wolbachia density varies according to the infection status of individuals, while the specific density of each Wolbachia strain remains constant regardless of the presence of other strains. This suggests that Wolbachia strains do not compete with one another within the same host individual, and that a strain-specific regulatory mechanism is operating. We discuss the regulatory mechanisms that are involved, and how this process might have evolved as a response to selective pressures acting on both partners. [source] Spatial population structure in a patchily distributed beetleMOLECULAR ECOLOGY, Issue 4 2001Tomas Roslin Abstract The dynamics and evolution of populations will critically depend on their spatial structure. Hence, a recent emphasis on one particular type of structure , the metapopulation concept of Levins , can only be justified by empirical assessment of spatial population structures in a wide range of organisms. This paper focuses on Aphodius fossor, a dung beetle specialized on cattle pastures. An agricultural database was used to locate nearly 50 000 local populations of A. fossor in Finland. Several independent methods were then used to quantify key processes in this vast population system. Allozyme markers and mitochondrial DNA (mtDNA) sequences were applied to examine genetic differentiation of local populations and to derive indirect estimates of gene flow. These estimates were compared to values expected on the basis of direct observations of dispersing individuals and assessments of local effective population size. Molecular markers revealed striking genetic homogeneity in A. fossor. Differentiation was only evident in mtDNA haplotype frequencies between the isolated Ĺland islands and the Finnish mainland. Thus, indirect estimates of gene flow agreed with direct observations that local effective population size in A. fossor is large (hundreds of individuals), and that in each generation, a substantial fraction (approximately one-fifth) of the individuals move between populations. Large local population size, extreme haplotype diversity and a high regional incidence of A. fossor all testify against recurrent population turnover. Taken together, these results provide strong evidence that the whole mainland population of A. fossor is better described as one large ,patchy population', with substantial movement between relatively persistent local populations, than as a classical metapopulation. [source] Genetic structure of seven Mexican indigenous populations based on five polymarker lociAMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 1 2003Leonora Buentello-Malo This descriptive study investigates the genetic structure of seven Mexican indigenous populations (Mixteca Alta, Mixteca Baja, Otomies, Purepecha, Nahuas-Guerrero, Nahuas-Xochimilco, and Tzeltales) on the basis of five PCR-based polymorphic DNA loci: LDLR, GYPA, HBGG, D7S8, and GC. Genetic distance and diversity analyses indicate that these Mexican indigenous are similar and that more than 96% of the total gene diversity (HT) can be attributed to individual variation within populations. Mixteca-Alta, Mixteca-Baja, and Nahuas-Xochimilco show indications of higher admixture with European-derived persons. The demonstration of a relative genetic homogeneity of Mexican Indians for the markers studied suggests that this population is suitable for studying disease-marker associations in the search for candidate genes of complex diseases. Am. J. Hum. Biol. 15:23,28, 2003. © 2002 Wiley-Liss, Inc. [source] mtDNA variability in two Bantu-speaking populations (Shona and Hutu) from Eastern Africa: Implications for peopling and migration patterns in sub-Saharan AfricaAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 2 2009Loredana Castrě Abstract In this study, we report novel data on mitochondrial DNA in two of the largest eastern Bantu-speaking populations, the Shona from Zimbabwe and the Hutu from Rwanda. The goal is to evaluate the genetic relationships of these two ethnic groups with other Bantu-speaking populations. Moreover, by comparing our data with those from other Niger-Congo speaking populations, we aim to clarify some aspects of evolutionary and demographic processes accompanying the spread of Bantu languages in sub-Saharan Africa and to test if patterns of genetic variation fit with models of population expansion based on linguistic and archeological data. The results indicate that the Shona and Hutu are closely related to the other Bantu-speaking populations. However, there are some differences in haplogroup composition between the two populations, mainly due to different genetic contributions from neighboring populations. This result is confirmed by estimates of migration rates which show high levels of gene flow not only between pairs of Bantu-speaking populations, but also between Bantu and non-Bantu speakers. The observed pattern of genetic variability (high genetic homogeneity and high levels of gene flow) supports a linguistic model suggesting a gradual spread of Bantu-speakers, with strong interactions between the different lines of Bantu-speaker descent, and is also in agreement with recent archeological findings. In conclusion, our data emphasize the role that population admixture has played at different times and to varying degrees in the dispersal of Bantu languages. Am J Phys Anthropol, 2009. © 2009 Wiley-Liss, Inc. [source] Genetic continuity after the collapse of the Wari empire: Mitochondrial DNA profiles from Wari and post-Wari populations in the ancient AndesAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 1 2009Brian M. Kemp Abstract The Wari empire flourished in the central, highland Peruvian Andes from AD 600,1000, and although the events that led to its demise are unknown, archaeological evidence indicates that Wari control waned at the end of the first millennium. Here, we test the hypothesis that, despite the major shift in social and political organization at the fall of the Wari empire, the mitochondrial DNA (mtDNA) composition of populations from the Ayacucho Basin, the former imperial heartland of the empire, remained essentially unchanged. Results show that mtDNA haplogroup frequencies among the Wari and post-Wari groups differ, but the difference is not statistically significant (,2 = 5.886, df = 3, P = 0.1172). This is the first study in the Andes to use haplotypic data to evaluate the observed genetic distance between two temporally distinct prehispanic populations (FST = 0.029) against modeled expectations of four possible evolutionary scenarios. None of these simulations allowed the rejection of continuity. In total, at both the haplogroup and haplotype levels these data do not allow us to reject the hypothesis that post-Wari individuals sampled in this study are the maternal descendants of those sampled from the Wari era site of Conchopata. However, genetic homogeneity in the mitochondrial gene pool, as seen in the late prehispanic southern Andes, may also characterize our study region. But, prior to this research, this was unknown. If our new data show mtDNA homogeneity, then this could limit the detection of female migration if, in fact, it occurred. Nonetheless, the novel mtDNA data presented here currently do not support the hypothesis that there was an influx of genetically distinct females into the former Wari heartland after the Wari collapse. Am J Phys Anthropol, 2009. © 2009 Wiley-Liss, Inc. [source] Analysis of mitochondrial DNA diversity in Burkina Faso populations confirms the maternal genetic homogeneity of the West African goatANIMAL GENETICS, Issue 3 2009L. J. Royo Summary To date, no comprehensive study has been performed on mitochondrial genetic diversity of the West African goat. Here, we analysed a 481-bp fragment of the HVI region of 111 goats representing four native West African populations, namely the three main Burkina Faso breeds, zoo-farm kept Dwarf goats and endangered Spanish goat breeds used as the outgroup. Analyses gave 83 different haplotypes with 102 variable sites. Most haplotypes (65) were unique. Only three haplotypes were shared between populations. Haplotypes were assigned to cluster A except for H45 (belonging to the Spanish Bermeya goat) which was assigned to cluster C. amova analysis showed that divergence between groups (,CT) was not statistically significant regardless of whether the partition in two hierarchical levels that was fitted included Spanish samples or not. The West African goat scenario shown here is consistent with that previously reported for the species: haplogroup A is predominant and has a very high haplotype diversity regardless of the geographic area or sampled breed. The large phenotypic differences observable between the West African Dwarf and Sahelian long-legged goat populations are not detectable with mitochondrial markers. Moreover, a previously suggested introgression of Sahelian goat southwards because of desertification could not be assessed using mtDNA information. [source] Genetic Heterogeneity of IcelandersANNALS OF HUMAN GENETICS, Issue 1 2003E. Árnason Summary Recently statements have been made about a special ,genetic homogeneity' of the Icelanders that are at variance with earlier work on blood groups and allozymes. To validate these claims an extensive reanalysis was undertaken of mtDNA variation by examining primary data from original sources on 26 European populations. The results show that Icelanders are among the most genetically heterogeneous Europeans by the mean number of nucleotide differences as well as by estimates of , parameters of the neutral theory. The distribution of pairwise differences in general has the same shape as European populations and shows no evidence of bottlenecks of numbers in Iceland. The allelic frequency distribution of Iceland is relatively even with a large number of haplotypes at polymorphic frequencies contrasting with other countries. This is a signature of admixture during the founding or history of Iceland. Assumptions of models used to simulate number of haplotypes at sampling saturation for comparing populations are violated to different degrees by various countries. Anomalies identified in data in previous reports on Icelandic mtDNA variation appear to be due to errors in publicly accessible databases. This study demonstrates the importance of basing analyses on primary data so that errors are not propagated. Claims about special genetic homogeneity of Icelanders are not supported by evidence. [source] Population structure in the catfish Trichogenes longipinnis: drift offset by asymmetrical migration in a tiny geographic rangeBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 2 2009KELLY R. ZAMUDIO Based on population genetic theory and empirical studies of small populations, we expect that species with very small ranges (narrow endemics) will exhibit reduced genetic diversity, increasing their susceptibility to the negative effects of genetic homogeneity. Although this pattern of reduced diversity applies to most narrow endemics, conservation biologists have yet to identify a general pattern for the degree of spatial population genetic structure expected in species with very small ranges. In part, this is because the degree of population structure within narrow endemics will be highly variable depending on the equilibrium between the homogenizing effects of dispersal and the diversifying effects of drift and local selection in small populations, thus precluding general predictions about the relative importance of small range, small population sizes, and habitat patchiness for maintaining genetic diversity in narrowly-distributed species. We document a striking example of high population structure in the tiny geographic range of a stream-dwelling catfish, Trichogenes longipinnis, endemic to the Atlantic Forest of Brazil. The maintenance of this diversity results from a combination of asymmetrical and limited dispersal, and drift in small populations. Our results highlight the need to understand population structure, and not only overall genetic diversity, of narrowly-distributed species for their conservation planning. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 97, 259,274. [source] Genetic structure of the endangered perennial plant Eryngium alpinum (Apiaceae) in an alpine valleyBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 4 2008MYRIAM GAUDEUL We investigated the genetic structure of Eryngium alpinum (Apiaceae) in an Alpine valley where the plant occurs in patches of various sizes. In a conservation perspective, our goal was to determine whether the valley consists of one or several genetic units. Habitat fragmentation and previous observations of restricted pollen/seed dispersal suggested pronounced genetic structure, but gene dispersal often follows a leptokurtic distribution, which may lead to weak genetic structure. We used nine microsatellite loci and two nested sampling designs (50 × 50 m grid throughout the valley and 2 × 2 m grid in two 50 × 10 m quadrats). Within the overall valley, F -statistics and Bayesian approaches indicated high genetic homogeneity. This result might be explained by: (1) underestimation of long-distance pollen/seed dispersal by in situ experiments and (2) too recent fragmentation events to build up genetic structure. Spatial autocorrelation revealed isolation by distance on the overall valley but this pattern was much more pronounced in the 50 × 10 m quadrats sampled with a 2-m mesh. This was probably associated with limited primary seed dispersal, leading to the spatial clustering of half-sibs around maternal plants. We emphasize the interest of nested sampling designs and of combining several statistical tools. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society, 2008, 93, 667,677. [source] Genetic Heterogeneity of IcelandersANNALS OF HUMAN GENETICS, Issue 1 2003E. Árnason Summary Recently statements have been made about a special ,genetic homogeneity' of the Icelanders that are at variance with earlier work on blood groups and allozymes. To validate these claims an extensive reanalysis was undertaken of mtDNA variation by examining primary data from original sources on 26 European populations. The results show that Icelanders are among the most genetically heterogeneous Europeans by the mean number of nucleotide differences as well as by estimates of , parameters of the neutral theory. The distribution of pairwise differences in general has the same shape as European populations and shows no evidence of bottlenecks of numbers in Iceland. The allelic frequency distribution of Iceland is relatively even with a large number of haplotypes at polymorphic frequencies contrasting with other countries. This is a signature of admixture during the founding or history of Iceland. Assumptions of models used to simulate number of haplotypes at sampling saturation for comparing populations are violated to different degrees by various countries. Anomalies identified in data in previous reports on Icelandic mtDNA variation appear to be due to errors in publicly accessible databases. This study demonstrates the importance of basing analyses on primary data so that errors are not propagated. Claims about special genetic homogeneity of Icelanders are not supported by evidence. [source] | |||||||||||||||||||||||||