RESUMO
OBJECTIVE: A disintegrin and metalloproteinase with thrombospondin motifs 5 (ADAMTS5) is a key enzyme in degradation of cartilage in osteoarthritis (OA). We report the pharmacological characterization of GLPG1972/S201086, a new, potent and selective small-molecule ADAMTS5 inhibitor. METHODS: Potency and selectivity of GLPG1972/S201086 for ADAMTS5 were determined using fluorescently labeled peptide substrates. Inhibitory effects of GLPG1972/S201086 on interleukin-1α-stimulated glycosaminoglycan release in mouse femoral head cartilage explants and on interleukin-1ß-stimulated release of an ADAMTS5-derived aggrecan neoepitope (quantified with ELISA) in human articular cartilage explants were determined. In the destabilization of the medial meniscus (DMM) mouse and menisectomized (MNX) rat models, effects of oral GLPG1972/S201086 on relevant OA histological and histomorphometric parameters were evaluated. RESULTS: GLPG1972/S201086 inhibited human and rat ADAMTS5 (IC50 ± SD: 19 ± 2 nM and <23 ± 1 nM, respectively), with 8-fold selectivity over ADAMTS4, and 60->5,000-fold selectivity over other related proteases in humans. GLPG1972/S201086 dose-dependently inhibited cytokine-stimulated aggrenolysis in mouse and human cartilage explants (100% at 20 µM and 10 µM, respectively). In DMM mice, GLPG1972/S201086 (30-120 mg/kg b.i.d) vs vehicle reduced femorotibial cartilage proteoglycan loss (23-37%), cartilage structural damage (23-39%) and subchondral bone sclerosis (21-36%). In MNX rats, GLPG1972/S201086 (10-50 mg/kg b.i.d) vs vehicle reduced cartilage damage (OARSI score reduction, 6-23%), and decreased proteoglycan loss (â¼27%) and subchondral bone sclerosis (77-110%). CONCLUSIONS: GLPG1972/S201086 is a potent, selective and orally available ADAMTS5 inhibitor, demonstrating significant protective efficacy on both cartilage and subchondral bone in two relevant in vivo preclinical OA models.
Assuntos
Proteína ADAMTS5 , Piperazinas , Animais , Humanos , Camundongos , Ratos , Proteína ADAMTS5/antagonistas & inibidores , Piperazinas/química , Piperazinas/farmacologiaRESUMO
Complement C5 deficiency (C5D) is a rare primary immunodeficiency associated with recurrent infections, particularly meningitis, by Neisseria species. To date, studies to elucidate the molecular basis of hereditary C5D have included fewer than 40 families, and most C5 mutations (13 of 17) have been found in single families. However, the recently described C5 p.A252T mutation is reported to be associated with approximately 7% of meningococcal disease cases in South Africa. This finding raises the question of whether the mutation may be prevalent in other parts of Africa or other continental regions. The aim of this study was to investigate the prevalence of C5 p.A252T in Africa and other regions and discuss the implications for prophylaxis against meningococcal disease. In total, 2710 samples from healthy donors within various populations worldwide were analysed by quantitative polymerase chain reaction (qPCR) assay to detect the C5 p.A252T mutation. Eleven samples were found to be heterozygous for p.A252T, and nine of these samples were from sub-Saharan African populations (allele frequency 0·94%). Interestingly, two other heterozygous samples were from individuals in populations outside Africa (Israel and Pakistan). These findings, together with data from genomic variation databases, indicate a 0·5-2% prevalence of the C5 p.A252T mutation in heterozygosity in sub-Saharan Africa. Therefore, this mutation may have a relevant role in meningococcal disease susceptibility in this geographical area.
Assuntos
População Negra/genética , Complemento C5/deficiência , Complemento C5/genética , Síndromes de Imunodeficiência/epidemiologia , Síndromes de Imunodeficiência/genética , Meningite Meningocócica/genética , Suscetibilidade a Doenças , Frequência do Gene , Doenças da Deficiência Hereditária de Complemento , Heterozigoto , Humanos , Programas de Rastreamento , Mutação , África do SulRESUMO
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
RESUMO
The Roma population is a European ethnic minority characterized by recent and multiple dispersals and founder effects. After their origin in South Asia around 1,500 years ago, they migrated West. In Europe, they diverged into ethnolinguistically distinct migrant groups that spread across the continent. Previous genetic studies based on genome-wide data and uniparental markers detected Roma founder events and West-Eurasian gene flow. However, to the best of our knowledge, it has not been assessed whether these demographic processes have equally affected both sexes in the population. The present study uses the largest and most comprehensive dataset of complete mitochondrial and Y chromosome Roma sequences to unravel the sex-biased patterns that have shaped their genetic history. The results show that the Roma maternal genetic pool carries a higher lineage diversity from South Asia, as opposed to a single paternal South Asian lineage. Nonetheless, the European gene flow events mainly occurred through the maternal lineages; however, a signal of this gene flow is also traceable in the paternal lineages. We also detect a higher female migration rate among European Roma groups. Altogether, these results suggest that sociocultural factors influenced the emergence of sex-biased genetic patterns at global and local scales in the Roma population through time.
Assuntos
Etnicidade/genética , Genética Populacional , Migração Humana , Roma (Grupo Étnico)/genética , Povo Asiático/genética , Cromossomos Humanos Y/genética , DNA Mitocondrial/genética , Etnicidade/história , Feminino , Efeito Fundador , Fluxo Gênico/genética , Variação Genética/genética , Haplótipos/genética , História Antiga , Humanos , Masculino , Caracteres Sexuais , População Branca/genéticaRESUMO
The analysis of geographically specific regions and the characterization of fine-scale patterns of genetic diversity may facilitate a much better understanding of the microevolutionary processes affecting local human populations. Here we generated genome-wide high-density SNP genotype data in 425 individuals from six geographical regions in Lithuania and combined our dataset with available ancient and modern data to explore genetic population structure, ancestry components and signatures of natural positive selection in the Lithuanian population. Our results show that Lithuanians are a homogenous population, genetically differentiated from neighbouring populations but within the general expected European context. Moreover, we not only confirm that Lithuanians preserve one of the highest proportions of western, Scandinavian and eastern hunter-gather ancestry components found in European populations but also that of an steppe Early to Middle Bronze Age pastoralists, which together configure the genetic distinctiveness of the Lithuanian population. Finally, among the top signatures of positive selection detected in Lithuanians, we identified several candidate genes related with diet (PNLIP, PPARD), pigmentation (SLC24A5, TYRP1 and PPARD) and the immune response (BRD2, HLA-DOA, IL26 and IL22).
Assuntos
Genética Populacional , Polimorfismo de Nucleotídeo Único , Seleção Genética , Adaptação Fisiológica/genética , Evolução Molecular , Humanos , LituâniaRESUMO
The recent description of a large amount of copy number variation (CNV) in the human genome has extended the concept of genome diversity. In this study we integrate the analysis of CNV and single nucleotide polymorphisms (SNPs) in the human CCL4L chemokine gene. CCL4L is a nonallelic copy of CCL4/MIP-1beta chemokine and displays a CNV that also includes the CCL3L gene, a nonallelic copy of CCL3/MIP-1alpha. This CNV and two functionally relevant CCL4L SNPs (rs4796195 and rs3744595) have been recently associated to HIV pathology in three independent studies. We have quantified the CCL4L copy number and genotyped both SNPs in samples from HGDP-CEPH Diversity Panel. A strong correlation between CCL4L CNV and one of the SNPs analyzed is found, whereas no significant linkage disequilibrium is found between the two SNPs despite their close distance (647 bp), suggesting a recent appearance of the second SNP when the diversity in the first one and CNV had already been generated. The present study points out that in genes with CNV, it may be a key issue to combine the assessment of gene copy number with the genotyping of relevant SNPs to understand the phenotypic impact of genome variation in the immune response.
Assuntos
Quimiocina CCL4/genética , Dosagem de Genes , Variação Genética , Genética Populacional , Polimorfismo de Nucleotídeo Único , África Subsaariana , Alelos , América , Povo Asiático/genética , Frequência do Gene , Heterogeneidade Genética , Genoma Humano , Heterozigoto , Humanos , OceaniaRESUMO
BACKGROUND: Care is the essence of the nursing role and is closely related to the concept of professional autonomy. Autonomy is implicated in power relations between doctors and nurses and between men and women. These relationships are closely linked to care practices and the inequality of nursing and medicine. PURPOSE: The aim of this study was to analyze nursing discourse regarding the concept of care and its relationship to the concept of autonomy and gender. METHODS: This is a historical study based on oral interviews that took place between November 2008 and February 2011. We interviewed 19 nursing professionals who currently worked at the Hospital of the Holy Spirit (near Barcelona) or had worked there between 1961 and 2010. Semistructured interviews were recorded, transcribed, and analyzed. RESULTS: We highlight four main themes: "a real nurse"; "more technology, less care"; "the fragility of autonomy"; and "the invisibility of nursing work." These themes show the contradictions in the nursing profession that are based on the concept of care. However, in daily practice, the concept of care varies. Time pressure distances the nursing practice from its theoretical context. Changes in the concept of care are related to transformations in the health system and nursing work. CONCLUSIONS/IMPLICATIONS FOR PRACTICE: Changes related to the autonomy of nursing are related to changes in the concept of care. In practice, care has a biomedical orientation. Care has become technologized and bureaucratized, which reduces the time that is spent with the patient. In a context in which medical authority predominates, nursing's struggle for autonomy is based on the recognition of the value of care. When care becomes invisible, the autonomy of nursing as a profession is threatened. This conclusion allows reflections about shifts in the concept of care and how they affect clinical practice and the autonomy of the nursing profession.
Assuntos
Liberdade , Cuidados de Enfermagem , Processo de Enfermagem , Autonomia Profissional , Fatores Sexuais , Feminino , Humanos , Masculino , EspanhaRESUMO
We surveyed the genetic variability of the glucocerebrosidase pseudogene (psGBA) in a worldwide sample of 100 human chromosomes. psGBA is the non-functional duplicate of the gene responsible for Gaucher disease (GBA), the most common lipid storage disorder. The existence of only one psGBA allele described until now, together with the high homology between GBA and psGBA, often prevented recognition of the complex alleles formed by the combination of GBA and psGBA, because psGBA variants could be confused with GBA mutations. In order to determine the variability existent in psGBA, the whole psGBA DNA segment was PCR-amplified and sequenced, and the genotype for all samples was obtained. The ascertainment of the phase among the heterozygous sites was possible through cloning and sequencing a single allele. Eighteen variable sites were detected along psGBA. Two of the variants already have been reported as Gaucher-causing mutations when present in GBA alleles. The other variants were unknown. The knowledge of the psGBA variants described in this report will allow identification of psGBA-GBA complex alleles that may aid in understanding the intricate phenotype-genotype relationship in Gaucher disease.
Assuntos
Doença de Gaucher/genética , Glucosilceramidase/genética , Pseudogenes/genética , Alelos , DNA/química , DNA/genética , Doença de Gaucher/enzimologia , Frequência do Gene , Variação Genética , Genótipo , Humanos , Dados de Sequência Molecular , Análise de Sequência de DNARESUMO
Several populations were typed for the hypervariable region II (HVRII) of the mitochondrial DNA (mtDNA) control region using immobilised sequence-specific oligonucleotide (SSO) probes. A total of 16 SSO probes was used to type 1081 individuals from eight different ethnic groups (African Americans, Somali, US Europeans, US Hispanics, Bosnians, Finns, Saami and Japanese). Data was compared with already published sequence data by analysis of principal components, genetic distances and analysis of the molecular variance (AMOVA). The analyses performed group the samples in several clusters according to their geographical origins. Most of the variability detected is assigned to differences between individuals and only 7% is assigned to differences among groups of populations within and between geographical regions. Several features are patent in the samples studied: Somali, as a representative East African population, seem to have experienced a detectable amount of Caucasoid maternal influence; different degrees of admixture in the US samples studied are detected; Finns and Saami belong to the European genetic landscape, although Saami present an outlier position attributable to a strong maternal founder effect. The technique used is a rapid and simple method to detect human variation in the mtDNA HVRII in a large number of samples, which might be useful in forensic and population genetic studies.
Assuntos
DNA Mitocondrial/genética , Variação Genética , Genética Populacional , Hibridização de Ácido Nucleico/métodos , Sondas de Oligonucleotídeos , Grupos Raciais/genética , Bósnia e Herzegóvina , Finlândia , Humanos , Japão , Somália , Estados UnidosRESUMO
Analysis of mitochondrial DNA (mtDNA) variation has become a useful tool for human population studies. We analysed the first hypervariable region of mitochondrial DNA control region (position 16024-16383) in 92 unrelated individuals from Galicia (Spain), a relatively isolated European population at the westernmost continental edge. Fifty different sequences defined by 56 variable positions were found. The frequency of the reference sequence reaches in Galicians its maximum value in Europe. Moreover, several genetic indexes confirm the low variability of our sample in comparison to data from 11 European and Middle Eastern populations. A parsimony tree of the sequences reveals a high simplicity of the tree, with few and small well defined clusters. These results place Galicians on the genetic edge of the European variation, bringing together all the traits of a cul-de-sac population with a striking similarity to the Basque population. The present results are fully compatible with a population expansion model in Europe during the Upper Paleolithic age. The genetic evidence revealed by the analysis of mtDNA shows the Galician population at the edge of a demographic expansion towards Europe from the Middle East.
Assuntos
DNA Mitocondrial/genética , Variação Genética , Sequência de Bases , Primers do DNA , Humanos , Dados de Sequência Molecular , Homologia de Sequência do Ácido Nucleico , EspanhaRESUMO
We have analysed a large set of autosomal short tandem repeat (STR) loci in several Arabic and Berber-speaking groups from north-west Africa (ie Moroccan Arabs, northern-central and southern Moroccan Berbers, Saharawis, and Mozabites). Two levels of analysis have been devised using two sets of 12STR loci, (D3S1358, vWA, FGA, THO1, TPOX, CSF1PO, D8S1179, D21S11, D18S51, D5S818, D13S317 and D7S820) and 21 (the former set plus D9S926, D11S2010, D13S767, D14S306, D18S848, D2S1328, D4S243, F13A1, and FES/FPS). For each set, data for a number of external reference populations were gathered from the literature. Several methods of analysis based on genetic distances (neighbour-joining trees, principal coordinate analysis, boundary detection), as well as AMOVA, showed that genetic differentiation among NW African populations was very low and devoid of any spatial pattern. When the NW African populations were grouped according to cultural or linguistic differences, the partition was not associated with genetic differentiation. Thus, it is likely that Arabisation was mainly a cultural process. A clear genetic difference was found between NW African populations and Iberians, which underscores the Gilbraltar Straits as a strong barrier to genetic exchange; nonetheless, some degree of gene flow into Southern Iberia may have existed. NW Africans were genetically closer to Iberians and to other Europeans than to African Americans.
Assuntos
Árabes/genética , Repetições de Microssatélites/genética , Sequências de Repetição em Tandem/genética , África do Norte/etnologia , Heterogeneidade Genética , Genética Populacional , HumanosRESUMO
In the cockroach Blattella germanica, the synthesis of vitellogenin is juvenile hormone III (JH III)-dependent. We have studied the effect of JH III upon vitellogenin gene expression in periovaric fat bodies incubated in vitro. Periovaric fat bodies were obtained from cardioallatectomized females. The response to JH III was measured in terms of vitellogenin and vitellogenin mRNA after 7 h of incubation. A hormonal concentration as low as 1 nM was enough to induce vitellogenin production and its release to the medium, whereas the concentration of 10 nM produced the maximal effects. Although the response of the vitellogenin gene to JH III is fast and efficient, it seems that the action is mediated by protein factors, given that cycloheximide treatment impairs the hormonal effect. The presence in the medium of brain extract (0.5 equivalents), corpora cardiaca (one pair) or hypertrehalosemic hormone (10(-7) or 10(-8) M), partially inhibited the response to JH III.
Assuntos
Blattellidae/genética , Corpo Adiposo/efeitos dos fármacos , Regulação da Expressão Gênica , Sesquiterpenos/farmacologia , Vitelogeninas/genética , Animais , Blattellidae/metabolismo , Química Encefálica , Corpora Allata/química , Corpora Allata/fisiologia , Cicloeximida/farmacologia , Corpo Adiposo/química , Corpo Adiposo/fisiologia , Feminino , Técnicas In Vitro , Hormônios de Inseto/farmacologia , Neuropeptídeos/farmacologia , Sistemas Neurossecretores/química , Sistemas Neurossecretores/fisiologia , Inibidores da Síntese de Proteínas/farmacologia , Vitelogeninas/metabolismoRESUMO
The present paper describes the effect of juvenile hormone III (JH III) upon vitellogenin (Vg) gene expression in cardioallatectomized females of Blattella germanica. Northern blot analyses of time course studies showed that Vg mRNA can be detected 2 h after the treatment with 1 microgram of JH III. Western blot analyses revealed that Vg protein is detectable 4 h after the same treatment. The study of the influence of the age showed that 48-h-old females seem more sensitive than 24-h-old females, whereas differences were less apparent between 48- and 72-h-old females. Dose-response studies indicated that 0.01 microgram of JH III is ineffective, whereas the doses of 0.1, 1 and 10 micrograms induced the synthesis of Vg in a dose-dependent fashion. Finally, the administration of three successive doses, of 0.01 microgram of JH III each, did not result in detectable Vg production, whereas two doses of 0.01 microgram followed by one of 1 microgram of JH III induced a greater response than that resulting from a sole dose of 1 microgram of JH III, which suggests that sub-effective doses of JH III elicit a priming effect on Vg production.
Assuntos
Blattellidae , Sesquiterpenos , Vitelogeninas/genética , Fatores Etários , Animais , Feminino , Expressão Gênica , Fatores de TempoRESUMO
AIMS: 1) To establish the relationship between the kind of microorganism that colonizes parenteral nutrition catheters and several risk factors related to catheterization and patient characteristics. 2) To investigate the risk factors associated to bacteremia episodes originated in these colonized catheters. METHOD: An observational, non-controlled, retrospective and cohorts study of the parenteral nutrition catheters implanted between 1988 and 1994 in our hospital. Risk factors were studied in 6 multiple-logistic regression models. RESULTS: 3632 catheters were studied. Incidences of colonization and bacteremia per 1000 days of catheterization were 17.56 and 3.93, respectively. Coagulase-negative staphyloccoci (CNS) were the most frequently isolated microorganisms. The colonization risk factors were: insertion site for all the microorganisms except fungi, catheterization time for CNS and fungi, hospitalization area, sex and age for CNS model, the existence of other infectious foci for Gram negative bacilli (GNB), S. aureus and other microorganisms, hypoalbuminemia for GNB model, and neoplasm for other microorganisms. The bacteremia risk factors were jugular insertion site, catheterization time greater than 10 days, catheter's hub colonization, and catheter colonization by gram-negative bacilli, fungi and S. aureus. CONCLUSION: Risk factors for catheter colonization vary depending on the microorganism which colonizes the catheter.
Assuntos
Bacteriemia/etiologia , Cateterismo/efeitos adversos , Cateteres de Demora/microbiologia , Nutrição Parenteral/efeitos adversos , Adulto , Fatores Etários , Idoso , Bacteriemia/microbiologia , Cateterismo/instrumentação , Estudos de Coortes , Contagem de Colônia Microbiana , Feminino , Fungos/isolamento & purificação , Bactérias Gram-Negativas/isolamento & purificação , Humanos , Masculino , Pessoa de Meia-Idade , Nutrição Parenteral/instrumentação , Análise de Regressão , Estudos Retrospectivos , Fatores de Risco , Fatores Sexuais , Staphylococcus/isolamento & purificaçãoRESUMO
The GHEP-ISFG Working Group performed a collaborative exercise to monitor the current practice of mitochondrial (mt)DNA reporting. The participating laboratories were invited to evaluate a hypothetical case example and assess the statistical significance of a match between the haplotypes of a case (hair) sample and a suspect. A total of 31 forensic laboratories participated of which all but one used the EMPOP database. Nevertheless, we observed a tenfold range of reported LR values (32-333.4), which was mainly due to the selection of different reference datasets in EMPOP but also due to different applied formulae. The results suggest the need for more standardization as well as additional research to harmonize the reporting of mtDNA evidence.
Assuntos
DNA Mitocondrial/genética , Bases de Dados Genéticas , Haplótipos , HumanosRESUMO
We report the results of the seventh edition of the GEP-ISFG mitochondrial DNA (mtDNA) collaborative exercise. The samples submitted to the participant laboratories were blood stains from a maternity case and simulated forensic samples, including a case of mixture. The success rate for the blood stains was moderate ( approximately 77%); even though four inexperienced laboratories concentrated about one-third of the total errors. A similar success was obtained for the analysis of mixed samples (78.8% for a hair-saliva mixture and 69.2% for a saliva-saliva mixture). Two laboratories also dissected the haplotypes contributing to the saliva-saliva mixture. Most of the errors were due to reading problems and misinterpretation of electropherograms, demonstrating once more that the lack of a solid devised experimental approach is the main cause of error in mtDNA testing.
Assuntos
Artefatos , Técnicas de Laboratório Clínico/normas , Impressões Digitais de DNA/normas , DNA Mitocondrial/genética , DNA/isolamento & purificação , Manchas de Sangue , Simulação por Computador , DNA/análise , DNA/genética , DNA Mitocondrial/sangue , DNA Mitocondrial/química , Interpretação Estatística de Dados , Bases de Dados Factuais , Feminino , Medicina Legal , Marcadores Genéticos , Cabelo/química , Haplótipos , Humanos , Filogenia , Reação em Cadeia da Polimerase , Polimorfismo Genético , Gravidez , Controle de Qualidade , Padrões de Referência , Saliva/químicaRESUMO
Neuregulin 1 (NRG1) is one of the most exciting candidate genes for schizophrenia since its first association with the disorder in an Icelandic population. Since then, many studies have analyzed allele and haplotype frequencies in European and Asian populations in cases and controls yielding varying results. We investigated the association of NRG1 with psychosis in a total sample set of 575 individuals from 151 Spanish nuclear families. We tested eight SNPs across 1.2 Mb along NRG1 including regions previously associated to schizophrenia in association studies. After correction for multiple testing, the TDT analysis for each marker did not show a significant over-transmission of alleles from the parents to the affected offspring for any of the markers (P > 0.05). The haplotypic analysis with TRANSMIT and PDT did not show preferential transmission for any of the haplotypes analyzed in our sample. These results do not seem to suggest that the investigated NRG1 markers play a role in schizophrenia in the Spanish population, although the finding of a trend for association with one SNP in the 3'of the gene warrants further investigation.
Assuntos
Neuregulina-1/genética , Esquizofrenia/genética , Adulto , Feminino , Genótipo , Haplótipos , Humanos , Desequilíbrio de Ligação , Masculino , Núcleo Familiar , Polimorfismo de Nucleotídeo Único , Esquizofrenia/etnologia , Espanha/epidemiologiaRESUMO
Neuregulin 1 (NRG1) is one of the most exciting candidate genes for schizophrenia in recent years since its first association with the disease in an Icelandic population. Since then, many association studies have analysed allele and haplotype frequencies in distinct populations yielding varying results: some have replicated the association, although with different alleles or haplotypes being associated, whereas others have failed to replicate the association. These contradictory results might be attributed to population differences in allele and haplotype frequencies. In order to approach this issue, we have typed 13 SNPs across this large 1.4 Mb gene, including two of the SNPs originally found associated with schizophrenia in the Icelandic population, the objective being to discover if the underlying cause of the association discrepancies to date may be due to population-specific genetic variation. The analyses have been performed in a total of 1088 individuals from 39 populations, covering most of the genetic diversity in the human species. Most of the SNPs analysed displayed differing frequencies according to geographical region. These allele differences are especially relevant in two SNPs located in a large intron of the gene, as shown by the extreme F(ST) values, which reveal genetic stratification correlated to broad continental areas. This finding may be indicative of the influence of some local selective forces on this gene. Furthermore, haplotype analysis reveals a clear clustering according to geographical areas. In summary, our findings suggest that NRG1 presents extreme population differences in allele and haplotype frequencies. We have given recommendations for taking this into account in future association studies since this diversity could give rise to erroneous results.
Assuntos
Ligação Genética , Genoma Humano , Proteínas do Tecido Nervoso/genética , Polimorfismo de Nucleotídeo Único , Esquizofrenia/genética , Frequência do Gene , Variação Genética , Genética Populacional , Haplótipos , Humanos , Neuregulina-1RESUMO
The Balkan Peninsula is a complex cultural mosaic comprising populations speaking languages from several branches of the Indo-European family and Altaic, as well as culturally-defined minorities such as the Aromuns who speak a Romance language. The current cultural and linguistic landscape is a palimpsest in which different peoples have contributed their cultures in a historical succession. We have sought to find any evidence of genetic stratification related to those cultural layers by typing both mtDNA and Y chromosomes, in Albanians, Romanians, Macedonians, Greeks, and five Aromun populations. We have paid special attention to the Aromuns, and sought to test genetically various hypotheses on their origins. MtDNA and Y-chromosome haplogroup frequencies in the Balkans were found to be similar to those elsewhere in Europe. MtDNA sequences and Y-chromosome STR haplotypes revealed decreased variation in some Aromun populations. Variation within Aromun populations was the primary source of genetic differentiation. Y-chromosome haplotypes tended to be shared across Aromuns, but not across non-Aromun populations. These results point to a possible common origin of the Aromuns, with drift acting to differentiate the separate Aromun communities. The homogeneity of Balkan populations prevented testing for the origin of the Aromuns, although a significant Roman contribution can be ruled out.