Native American gene flow into Polynesia predating Easter Island settlement.

The possibility of voyaging contact between prehistoric Polynesian and Native American populations has long intrigued researchers. Proponents have pointed to the existence of New World crops, such as the sweet potato and bottle gourd, in the Polynesian archaeological record, but nowhere else outside the pre-Columbian Americas1-6, while critics have argued that these botanical dispersals need not have been human mediated7. The Norwegian explorer Thor Heyerdahl controversially suggested that prehistoric South American populations had an important role in the settlement of east Polynesia and particularly of Easter Island (Rapa Nui)2. Several limited molecular genetic studies have reached opposing conclusions, and the possibility continues to be as hotly contested today as it was when first suggested8-12. Here we analyse genome-wide variation in individuals from islands across Polynesia for signs of Native American admixture, analysing 807 individuals from 17 island populations and 15 Pacific coast Native American groups. We find conclusive evidence for prehistoric contact of Polynesian individuals with Native American individuals (around AD 1200) contemporaneous with the settlement of remote Oceania13-15. Our analyses suggest strongly that a single contact event occurred in eastern Polynesia, before the settlement of Rapa Nui, between Polynesian individuals and a Native American group most closely related to the indigenous inhabitants of present-day Colombia.

Development of a small panel of SNPs to infer ancestry in Chileans that distinguishes Aymara and Mapuche components.

BACKGROUND: Current South American populations trace their origins mainly to three continental ancestries, i.e. European, Amerindian and African. Individual variation in relative proportions of each of these ancestries may be confounded with socio-economic factors due to population stratification. Therefore, ancestry is a potential confounder variable that should be considered in epidemiologic studies and in public health plans. However, there are few studies that have assessed the ancestry of the current admixed Chilean population. This is partly due to the high cost of genome-scale technologies commonly used to estimate ancestry. In this study we have designed a small panel of SNPs to accurately assess ancestry in the largest sampling to date of the Chilean mestizo population (n = 3349) from eight cities. Our panel is also able to distinguish between the two main Amerindian components of Chileans: Aymara from the north and Mapuche from the south. RESULTS: A panel of 150 ancestry-informative markers (AIMs) of SNP type was selected to maximize ancestry informativeness and genome coverage. Of these, 147 were successfully genotyped by KASPar assays in 2843 samples, with an average missing rate of 0.012, and a 0.95 concordance with microarray data. The ancestries estimated with the panel of AIMs had relative high correlations (0.88 for European, 0.91 for Amerindian, 0.70 for Aymara, and 0.68 for Mapuche components) with those obtained with AXIOM LAT1 array. The country's average ancestry was 0.53 ± 0.14 European, 0.04 ± 0.04 African, and 0.42 ± 0.14 Amerindian, disaggregated into 0.18 ± 0.15 Aymara and 0.25 ± 0.13 Mapuche. However, Mapuche ancestry was highest in the south (40.03%) and Aymara in the north (35.61%) as expected from the historical location of these ethnic groups. We make our results available through an online app and demonstrate how it can be used to adjust for ancestry when testing association between incidence of a disease and nongenetic risk factors. CONCLUSIONS: We have conducted the most extensive sampling, across many different cities, of current Chilean population. Ancestry varied significantly by latitude and human development. The panel of AIMs is available to the community for estimating ancestry at low cost in Chileans and other populations with similar ancestry.

Effects of folic acid fortification on orofacial clefts prevalence: a meta-analysis.

OBJECTIVE: Orofacial clefts (OFC) are the most prevalent craniofacial birth defect. Folic acid (FA) supplementation has been demonstrated as an effective intervention to reduce risk of OFC occurrence. However, the effect of mandatory FA fortification of wheat and/or maize flour on OFC prevalence has shown controversial results among countries adopting this policy. Thus, we performed a meta-analysis to synthesize the available evidence evaluating the global impact of this mandatory policy on OFC occurrence. DESIGN: Literature search in conventional and grey medical/scientific databases showed fifteen studies considering OFC prevalence in pre- and post-fortification periods with FA. The effect of this policy was evaluated by computing relative risk (RR) and separating samples into total OFC, non-syndromic forms, cleft lip with or without cleft palate (CL/P) and cleft palate only (CPO). RESULTS: We found a significant effect of FA fortification only on non-syndromic CL/P (RR=0·88; 95 % CI 0·81, 0·96), whereas neutral effects were detected for total OFC (syndromic plus non-syndromic) and CPO. CONCLUSIONS: Our results may reflect the different aetiology of syndromic OFC with respect to non-syndromic forms and the CL/P related to CPO. Although the number of non-syndromic CL/P samples was lower than that for total OFC, the absence of both between-study heterogeneity and publication bias leads us to conclude that FA fortification may have beneficial effects on non-syndromic CL/P.

Prevalence of the 35delG mutation in the GJB2 gene in two samples of non-syndromic deaf subjects from Chile.

Hearing loss is the most common inherited sensorial deficiency in humans; about 1 in 1000 children suffer from severe or profound hearing loss at birth. Mutations in the GJB2 gene are the most common cause of prelingual, non-syndromic autosomal recessive deafness in many populations; the c.35delG mutation is the most common in Caucasian populations. The frequency of the c.35delG mutation was estimated in two samples of deaf patients from Santiago, Chile. Unrelated non-syndromic sensorioneural deaf patients were examined: Group 1 consisted of 47 unrelated individuals with neurosensory deafness referred to the Chilean Cochlear Implant Program; Group 2 included 66 school children with prelingual deafness attending special education institutions for deaf people. Individuals with profound to moderate isolated neurosensory hearing loss with unknown etiology were included. The presence of the c.35delG mutation was evaluated by the allele-specific polymerase chain reaction method (PCR), and in some cases it was confirmed by direct DNA sequencing of the coding region of the GJB2 gene. Deaf relatives were present in 20.3% of the cases. We found 19.5% (22/113) patients with the c.35delG mutation, 6 of them homozygous; these rates are similar to frequencies found in other Latin American countries.

Greater prevalence of Y chromosome Q1a3a haplogroup in Y-microdeleted Chilean men: a case-control study.

PURPOSE: To determine the prevalence of South Amerindian Y chromosome in Chilean patients with spermatogenic failure and their association with classical and/or AZFc-partial Y chromosome deletions. METHODS: We studied 400 men, 218 with secretory azo/oligozoospermia (cases) and 182 controls (116 fertile and/or normozoospermic, and 66 azoospermic with normal spermatogenesis). After a complete testicular characterization (physical evaluation, hormonal and/or biopsy) peripheral blood was drawn to obtain DNA for Y chromosome microdeletions, AZFc-partial deletions and biallelic analysis by allele specific polymerase chain reaction (PCR) of the M3 (rs3894) single nucleotide polymorphism (SNP). RESULTS: Classical AZF microdeletions were found in 23 cases (Y-microdeleted). AZFc-partial deletions were observed in 10 cases (6 "gr/gr", 3 "b2/b3" and 1 "b1/b3") and 4 controls (4 "gr/gr"). The AZFc-partial deletions were mainly associated with the absence of DAZ1/DAZ2 (64 %). No significant differences in the prevalence of AZFc-partial deletions were observed between cases and controls. We observed a significant higher proportion of the Q1a3a haplogroup in Y-microdeleted men compared to patients with spermatogenic failure without deletions and control men (P<0.01 and P<0.05, respectively by Bonferroni test). Among them, patients with AZFb deletions had an increased prevalence of the Q1a3a haplogroup compared to controls, cases without deletions and to those with complete or partial-AZFc deletions (P<0.01, Bonferroni test). CONCLUSIONS: The Q1a3a South Amerindian lineage seems to increase the susceptibility to non AZFc microdeletions. On the other hand, in Chilean population the AZFc-partial deletions ("gr/gr", "b1/b3" and/or "b2/b3") does not seem to predispose to severe spermatogenic impairment.

Probability of exclusion in paternity testing: time to reassess.

The average exclusion probability is a measure of efficiency in paternity testing; it refers to the a priori ability of a battery of tests to detect paternity inconsistencies. This parameter measures the capacity of the system to detect a false accusation of paternity. Traditionally, this average exclusion probability has been estimated as the probability of excluding a man who is not the father by an inconsistency in at least one of the studied loci. We suggest that this criterion should be corrected, as currently the presumed father is excluded when at least three genetic inconsistencies are found with the child being tested, not just one. This change of criterion has occurred because of the use of microsatellite loci, whose mutation rates are much greater than those of the coding genes used previously in paternity studies. We propose the use of the average probability of exclusion for at least three loci (not only one), as an honest measure of the combined probability of exclusion of several loci, and we propose an algebraic expression to calculate it.

Development of a small panel of SNPs to infer ancestry in Chileans that distinguishes Aymara and Mapuche components

BACKGROUND: Current South American populations trace their origins mainly to three continental ancestries, i.e. European, Amerindian and African. Individual variation in relative proportions of each of these ancestries may be confounded with socio-economic factors due to population stratification. Therefore, ancestry is a potential confounder variable that should be considered in epidemiologic studies and in public health plans. However, there are few studies that have assessed the ancestry of the current admixed Chilean population. This is partly due to the high cost of genome-scale technologies commonly used to estimate ancestry. In this study we have designed a small panel of SNPs to accurately assess ancestry in the largest sampling to date of the Chilean mestizo population (n = 3349) from eight cities. Our panel is also able to distinguish between the two main Amerindian components of Chileans: Aymara from the north and Mapuche from the south. RESULTS: A panel of 150 ancestry-informative markers (AIMs) of SNP type was selected to maximize ancestry informativeness and genome coverage. Of these, 147 were successfully genotyped by KASPar assays in 2843 samples, with an average missing rate of 0.012, and a 0.95 concordance with microarray data. The ancestries estimated with the panel of AIMs had relative high correlations (0.88 for European, 0.91 for Amerindian, 0.70 for Aymara, and 0.68 for Mapuche components) with those obtained with AXIOM LAT1 array. The country's average ancestry was 0.53 ± 0.14 European, 0.04 ± 0.04 African, and 0.42 ± 0.14 Amerindian, disaggregated into 0.18 ± 0.15 Aymara and 0.25 ± 0.13 Mapuche. However, Mapuche ancestry was highest in the south (40.03%) and Aymara in the north (35.61%) as expected from the historical location of these ethnic groups. We make our results available through an online app and demonstrate how it can be used to adjust for ancestry when testing association between incidence of a disease and nongenetic risk factors. CONCLUSIONS: We have conducted the most extensive sampling, across many different cities, of current Chilean population. Ancestry varied significantly by latitude and human development. The panel of AIMs is available to the community for estimating ancestry at low cost in Chileans and other populations with similar ancestry.

Muir-Torre syndrome: case report and molecular characterization.

CONTEXT: Muir-Torre syndrome is a rare autosomal dominant genodermatosis caused by mutations in the mismatch repair genes. It is characterized by the presence of sebaceous skin tumors and internal malignancies, affecting mainly the colon, rectum and urogenital tract. Awareness of this syndrome among physicians can lead to early diagnosis of these malignancies and a better prognosis. CASE REPORT: We report the case of a Chilean patient who, over the course of several years, had multiple skin lesions, endometrial cancer and colon cancer. The syndrome was diagnosed using molecular techniques such as microsatellite instability analysis, immunohistochemistry and DNA sequencing, which allowed us to find the causative mutation. CONCLUSION: Molecular diagnostics is a highly useful tool, since it allows clinicians to confirm the presence of mutations causing Muir-Torre syndrome. It is complementary to the analysis of the clinical data, such as dermatological presentation, presence of visceral malignancies and family history of colorectal tumors, and it provides important knowledge to help physicians and patients choose between treatment options.

Aneurismal subarachnoid hemorrhage in a Chilean population, with emphasis on risk factors.

BACKGROUND: Subarachnoid Hemorrhage (SAH) is caused principally by the rupture of intracranial aneurisms. Important risk factors have been described such as age, sex, hypertension (HT) and season of the year, among others. The objective is to investigate the demographic characteristics and possible risk factors in a population of Chilean patients. METHODS: This retrospective study was based on the analysis of 244 clinical records of patients diagnosed with aneurismal SAH who were discharged from the Instituto de Neurocirugía ASENJO in Santiago, Chile. RESULTS: The mean age of patients was 49.85 years and the male:female ratio was 1:2.7. The signs and symptoms were not different between sexes; cephalea (85.7%) was predominant, followed by loss of consciousness, vomiting/nausea and meningeal signs. Risk factors included sex, age and HT. Concordant with other reports, the incidence of SAH was greatest in spring. CONCLUSIONS: The demographic characteristics and risk factors observed in patients with aneurismal SAH treated in ASENJO were comparable to those of other populations. We were not able to conclude that tobacco and alcohol consumption were risk factors for this population.

DNA extraction from formalin-fixed laryngeal biopsies: Comparison of techniques.

CONCLUSION: PCR-quality DNA could be extracted from formalin-fixed paraffin-embedded (FFPE) samples with amplicons of at least 390 bp. Paraffin removal was not a necessary step. Proteinase K digestion was as efficient as the commercial kit for DNA extraction with a lower cost. OBJECTIVES: To compare different DNA extraction protocols for FFPE samples and to describe the suitability of the extracted DNA for PCR reactions. METHODS: For deparaffinization the following techniques were compared: alkaline heat, xylene, and no removal. For DNA extraction, proteinase K digestion and organic extraction were compared. A commercial extraction kit was included as standard. DNA quality was assessed by PCR amplification of the HFE gene, for amplicons of 208 and 390 bp. RESULTS: Extraction with the commercial kit and proteinase K digestion were more efficient than other techniques, with no statistical difference between them for both amplicons. The proteinase K digestion buffer had a cost of U$ 0.2 per sample and the commercial kit of U$7 per sample.

[Evolution of prevalence rates of orofacial clefts in a maternity of a Chilean clinical hospital]. / 38 Años de vigilancia epidemiológica de labio leporino y paladar hendido en la maternidad del Hospital Clínico de la Universidad de Chile.

BACKGROUND: Orofacial clefts are common and have a great medical and social importance. The Latin American Study of Congenital Malformations (ECLAMC), has maintained an epidemiological surveillance of congenital malformations since 1969, allowing the evaluation of trends in the prevalence of malformations. AIM: To evaluate the evolution curve of prevalence rates of orofacial clefts from 1971 to 2008. MATERIAL AND METHODS: All cases of orofacial clefts, occurring in newborns from the maternity of a university hospital from January 2000 to December 2008, were recorded as part of the ECLAMC. Historical information about the rates of the malformation between 1971 and 1999, was obtained from previous manuscripts of the authors. RESULTS: In the study period, 15,635 children were born and 46 had cleft lip-palate (3). This rate is significantly higher than those observed previously, that fluctuated between 1.5 and 1.7. The prevalence rates of cleft lip remained stable from 1971 to 1999 and suffered a brisk and significant rise in the period 2000-2008 When the period is analyzed year by year, the increase in rates is observed in the last two years. The rates of cleft palate suffered a slight non significant rise until 2000. CONCLUSIONS: The increased rates of cleft lip palate observed in the last two years of the observation period may be a random result and should be monitored in the future.

Muir-Torre Syndrome: case report and molecular characterization / Sindrome de Muir-Torre: relato de caso e caracterizacao molecular

CONTEXT: Muir-Torre syndrome is a rare autosomal dominant genodermatosis caused by mutations in the mismatch repair genes. It is characterized by the presence of sebaceous skin tumors and internal malignancies, affecting mainly the colon, rectum and urogenital tract. Awareness of this syndrome among physicians can lead to early diagnosis of these malignancies and a better prognosis. CASE REPORT: We report the case of a Chilean patient who, over the course of several years, had multiple skin lesions, endometrial cancer and colon cancer. The syndrome was diagnosed using molecular techniques such as microsatellite instability analysis, immunohistochemistry and DNA sequencing, which allowed us to find the causative mutation. CONCLUSION: Molecular diagnostics is a highly useful tool, since it allows clinicians to confirm the presence of mutations causing Muir-Torre syndrome. It is complementary to the analysis of the clinical data, such as dermatological presentation, presence of visceral malignancies and family history of colorectal tumors, and it provides important knowledge to help physicians and patients choose between treatment options. .

CONTEXTO: A síndrome de Muir-Torre é uma genodermatose autossômica dominante rara causada por mutações nos genes de reparo de incorreções. Caracteriza-se pela presença de tumores sebáceos da pele e doenças malignas internas, afetando principalmente cólon, reto e trato urogenital. A consciência desta síndrome pelos médicos pode levar ao diagnóstico precoce dessas doenças malignas e a um melhor prognóstico. RELATO DE CASO: Relatamos o caso de uma paciente chilena que, ao longo de vários anos, teve lesões cutâneas múltiplas, câncer de endométrio e câncer de cólon. A síndrome foi diagnosticada com técnicas moleculares, como a análise de instabilidade de microssatélites, imunoistoquímica e sequenciamento de DNA, o que nos permitiu encontrar a mutação causadora. CONCLUSÃO: Diagnóstico molecular é uma ferramenta muito útil, uma vez que permite que os clínicos confirmem a presença de mutações causadoras de síndrome de Muir-Torre. É complementar para a análise dos dados clínicos, tais como a apresentação dermatológica, a presença de doenças malignas viscerais e história familiar de tumores colorrectais, e fornece conhecimentos importantes para ajudar os médicos e os pacientes a escolher entre opções de tratamento. .

Prevalence of the 35delG mutation in the GJB2 gene in two samples of non-syndromic deaf subjects from Chile

Hearing loss is the most common inherited sensorial deficiency in humans; about 1 in 1000 children suffer from severe or profound hearing loss at birth. Mutations in the GJB2 gene are the most common cause of prelingual, non-syndromic autosomal recessive deafness in many populations; the c.35delG mutation is the most common in Caucasian populations. The frequency of the c.35delG mutation was estimated in two samples of deaf patients from Santiago, Chile. Unrelated non-syndromic sensorioneural deaf patients were examined: Group 1 consisted of 47 unrelated individuals with neurosensory deafness referred to the Chilean Cochlear Implant Program; Group 2 included 66 school children with prelingual deafness attending special education institutions for deaf people. Individuals with profound to moderate isolated neurosensory hearing loss with unknown etiology were included. The presence of the c.35delG mutation was evaluated by the allele-specific polymerase chain reaction method (PCR), and in some cases it was confirmed by direct DNA sequencing of the coding region of the GJB2 gene. Deaf relatives were present in 20.3% of the cases. We found 19.5% (22/113) patients with the c.35delG mutation, 6 of them homozygous; these rates are similar to frequencies found in other Latin American countries.

[Prevalence of microtia and anotia at the maternity of the University of Chile Clinical Hospital]. / Prevalencia de nacimiento de microtia-anotia. Maternidad del Hospital Clínico de la Universidad de Chile, período 1983-2005.

BACKGROUND: Microtia is a congenital defect characterized by disturbances in the size and form of the ear lobe. Anotia corresponds to the absence of the ear lobe. AIM: To study the prevalence of microtia and anotia at the Maternity of the University of Chile Clinical Hospital. MATERIAL AND METHODS: Analysis of the database of the Latin American Collaborative Study of Congenital Defects (ECLAMC). All newborns and stillborns with congenital defects are incorporated to this database. RESULTS: The prevalence of microtia-anotia in the period 1982-2001 was 8.7 per 10,000 born alive. Chilean hospitals have an uniform prevalence of 5.2 per 10,000 born alive. Thirty seven percent presented as isolated malformations and the rest were associated to other defects. Eighty six percent of non isolated cases were part of a syndrome. Sixty eight percent were mild or moderate forms and the rest, severe forms. Two cases were stillborns and two newborns died before hospital discharge. CONCLUSIONS: The prevalence of microtia in this hospital and in the rest of Chilean hospitals is significantly higher than in the rest of non Chilean hospitals participating in the ECLAMC, that is 4.1 per 10,000 born alive.

[Prevalence of congenital malformations and low weight at birth among teenage mothers]. / Prevalencia al nacimiento de malformaciones congénitas y de menor peso de nacimiento en hijos de madres adolescentes.

BACKGROUND: In Chile, 14 to 16% of births occur in teenage mothers. These mothers apparently have a higher frequency of premature labor, low birth weight and congenital malformations. AIM: To assess the frequency of prematurity, congenital malformations and weight at birth among the offspring of adolescent mothers. PATIENTS AND METHODS: The births occurred in a hospital between 1982 and 2001, were analyzed using the Latin American Collaborative Study for Congenital Malformations (ECLAMC) data base. Mothers were classified as teenagers when their age ranged between 10 and 19 years old and older when their age was over 20 years old. All women were subdivided as cases and controls. RESULTS: The sample was formed by 894 teenage and 806 older mothers. Seven percent of both teenage and older mothers had offspring with one or more malformations. The incidence of low birth weight newborns and of prematurity was also similar in both groups of mothers. CONCLUSIONS: In this sample, offspring of teenage mothers do not have a higher frequency of malformations, low birth weight or prematurity.

[Congenital malformations and chronic diseases of the mother. Latin American Collaborative Study of Congenital Malformations (ECLAMC) 1971-1999]. / Malformaciones congénitas y patología crónica de la madre. Estudio ECLAMC 1971-1999.

BACKGROUND: Several maternal diseases, such as diabetes mellitus or high blood pressure, are associated with a higher risk for fetal or neonatal problems. AIM: To study the association between chronic diseases of the mother and congenital malformations. MATERIAL AND METHODS: Review of the records of the Latin American Collaborative Study of Congenital Malformations (ECLAMC) at the University of Chile Clinical Hospital. A sample of 383 mothers with a chronic disease was compared with 297 healthy mothers. The presence of congenital malformations in the newborns was studied. The odds ratio (OR) of a mother to have a child with a congenital malformation was calculated. RESULTS: Mothers with bronchial asthma, diabetes mellitus, hypertension and hypothyroidism had an OR over 1 of having a child with a congenital malformation. No association between maternal obesity and offspring malformations was observed. Offspring of diabetic mothers had 8.95 times more probabilities of having a major malformation and 4.95 times more probabilities of having a minor defect. CONCLUSIONS: Offspring of mothers with diabetes mellitus, bronchial asthma, hypertension or hypothyroidism have a higher risk of presenting a congenital malformation, when compared with offspring of healthy mothers.

[Congenital malformations of the digestive system. Maternity Clinical Hospital at the University of Chile. 1991-2001]. / Malformaciones congénitas del sistema digestivo. Maternidad Hospital Clínico de la Universidad de Chile. Período 1991-2001.

BACKGROUND: There were 26,617 births attended at the University of Chile Clinical Hospital, of which 0.63% were stillborn. A frequency of malformations of 7.2 per born alive and of 22.1 per stillborn was detected in this population. AIM: To report the frequency of digestive system congenital malformations in this population. MATERIAL AND METHODS: Analysis of data from the births that occurred at the University of Chile Hospital, that was gathered using codified form for the Latin American Collaborative Study for Congenital Malformations. RESULTS: Ninety seven digestive congenital malformations were detected, with a rate of 26.4 per 10,000 born alive and 12.2 per 10,000 stillborn. Diaphragmatic hernia was the most frequent malformation found, followed by imperforated anus, onphalocele and esophageal atresia. There was a secular increase in the frequency of these malformations. CONCLUSIONS: The frequency of digestive system malformations is higher than in the rest of hospitals participating in the Latin American Collaborative Study for Congenital Malformations.

[Prevalence of chromosomal aberrations at birth in the Clinical Hospital of Universidad de Chile, 1990-2001]. / Prevalencia al nacimiento de aberraciones cromosómicas en el Hospital Clínico de la Universidad de Chile. Período 1990-2001.

BACKGROUND: A cytogenetical study should be performed to every newborn with malformations. If a chromosomal aberration is found, parents must be studied to give an adequate genetic advise. AIM: To study the frequency of chromosomal aberrations in newborns with malformations. PATIENTS AND METHODS: In the Clinical Hospital of the University of Chile all malformations in newborns are registered, as part of the Collaborative Latin American Study of Congenital Malformations (ECLAMC). The frequency of chromosomal aberrations, determined by cytogenetical studies, was determined in newborns with malformations. RESULTS: In the study period, there were 32,214 births. Of these, 2,268 live newborns and 43 stillbirths had malformations. Ninety nine children with malformations had chromosomal aberrations (4.3%). Trisomy 21 was the most common aberration with a rate of 23/10,000 births, followed by trisomy 18 with a rate of 4/10,000 and trisomy 18 with a rate of 1.2/10,000. Ninety four percent of these children were born alive and 16.1% died before discharge from the hospital. The masculinity indexes for Down syndrome and for trisomy 18 were 0.38 and 0.61 respectively. CONCLUSIONS: A higher frequency of female gender for trisomy 21 and male gender for trisomy 18 has not been reported previously.

Larval interactions between a colonizing population of Drosophila subobscura and three established species of Drosophila in Chile

A viabilidade ovo-adulto e o tempo de desenvolvimento em Drosophila subobscura é bastante modificada pela acumulaçäo de resíduos bióticos de larvas de D. pavani, D. immigrans e D. melanogaster. Este efeito poderia ser um fator regulador importante para estas espécies na natureza