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G Modiano

Publications and source records attributed to G Modiano.

At least 19 recordsLinked to original sources
PubMed2000

A new approach for identifying non-pathogenic mutations. An analysis of the cystic fibrosis transmembrane regulator gene in normal individuals.

Given q as the global frequency of the alleles causing a disease, any allele with a frequency higher than q minus the cumulative frequency of the previously known disease-causing mutations (threshold) cannot be the cause of that disease. This principle was applied to the analysis of cystic fibrosis transmembrane conductance regulator (CFTR) mutations in order to decide whether they are the cause of cystic fibrosis. A total of 191 DNA samples from random individuals from Italy, France, and Spain were investigated by DGGE (denaturing gradient gel electrophoresis) analysis of all the coding and proximal non-coding regions of the gene. The mutations detected by DGGE were identified by sequencing. The sample size was sufficient to select essentially all mutations with a frequency of at least 0.01. A total of 46 mutations was detected, 20 of which were missense mutations. Four new mutations were identified: 1341+28 C/T, 2082 C/T, L1096R, and I11131V. Thirteen mutations (125 G/C, 875+40 A/G, TTGAn, IVS8-6 5T, IVS8-6 9T, 1525-61 A/G, M470V, 2694 T/G, 3061-65 C/A, 4002 A/G, 4521 G/A, IVS8 TG10, IVS8 TG12) were classified as non-CF-causing alleles on the basis of their frequency. The remaining mutations have a cumulative frequency far exceeding q; therefore, most of them cannot be CF-causing mutations. This is the first random survey capable of detecting all the polymorphisms of the coding sequence of a gene.

Cystic Fibrosis Transmembrane Conductance Regulato↗
PubMed1998

Two ethnic-specific polymorphisms in the human beta pseudogene of hemoglobin.

Two polymorphic sites, -107 C-->T and -100 G-->C with respect to the cap site of the human beta pseudogene of the hemoglobin gene, are described. They have been studied in five European, one Indian, two Asian, and two sub-Saharan African populations. The -107 C-->T site turned out to be polymorphic in all five European populations and the Indian population (pooled q = 0.142 +/- 0.018) and in the two Asian populations (pooled q = 0.073 +/- 0.025), but it was monomorphic in the two sub-Saharan populations. On the contrary, the -100 G-->C site was polymorphic in the two sub-Saharan samples (q = 0.093 +/- 0.024), but the variant allele was not found in any of the European, Indian, or Asian samples. Thus this only 8-bp-long stretch of DNA is informative for estimating the extent of genetic admixture in sub-Saharan Africans.

Africa South of the Sahara↗
PubMed1995

Genetic heterogeneity among the Hindus and their relationships with the other "Caucasoid" populations: new data on Punjab-Haryana and Rajasthan Indian states.

The genetic structure of Rajasthan Hindus and Punjab-Haryana Hindus and Sikhs has been studied for ABO, RH, APOC2, C6, C7, F13A, F13B, HP, ORM1, ACP1, ADA, AK1, ESD, GLO1, PGD, PGM1 subtyping, and PGP. This is the first genetic survey on Hindus of Rajasthan. Furthermore, many of these markers have never been studied on Hindus before (APOC2, C6, C7, F13A, F13B, ORM1, PGP). These data, together with those previously available for Hindus, have been utilized to analyze the within-Hindus genetic heterogeneity by RST statistic and correspondence analysis. The genetic relationships of Hindus to other Causcasoid populations were also investigated. In the first analysis, two eastern states (Orissa and Andhra Pradesh) were found to be quite separate from each other and clearly distinct from the northwestern and western states. Out of the markers which could not be utilized in this analysis, PGM1 subtyping turned out to discriminate between the Dravidian-speaking and the Indo-Aryan-speaking Hindus. The second analysis shows a clear-cut separation of Hindus from Europeans, with Near Eastern and Middle Eastern populations genetically in an intermediate position.

Blood Group Antigens↗
PubMed1995

Are the SSTR alleles stable enough to be considered monophyletic and hence reliable anthropogenetic markers? Linkage disequilibrium study on the (ACT)n COL1A2 SSTR.

An extremely low production rate of a polymorphic allele (formally called the mutation rate)--a prerequisite for using the allele as a marker (particularly for anthropogenetic purposes where the alleles must be assumed to be monophyletic)--cannot be taken for granted for alleles of highly polymorphic VNTRs, but a low production rate can be used to identify alleles produced by a single nucleotide substitution. This property was indirectly tested for the (ACT)n COL1A2 (of type I collagen) microsatellite SSTR (degree of heterozygosity H = 0.72) by searching for linkage disequilibria between the SSTR's four common alleles (n = 6, 8, 9, or 10) and three RFLPs of the same gene. A strong linkage disequilibrium between at least three of the four SSTR alleles and two of the three closely linked RFLPs has been demonstrated in a Sardinian population (Italy), a finding that suggests a low production rate of these alleles. Thus it seems that this highly polymorphic system and, by a reasonable extrapolation, other VNTRs with a comparable degree of heterozygosity may be valuable anthropogenetic markers, at least in distinguishing subgroups of a major ethnic group.

Adult↗
PubMed1995

Allele and haplotype frequency distribution of the EcoRI, RsaI, and MspI COL1A2 RFLPs among various human populations.

The EcoRI, RsaI, and MspI RFLPs (restriction fragment length polymorphisms) of the COL1A2 gene, one of the two genes that encode for the polypeptides of type I collagen, have been studied in four West African and two Asian populations to evaluate their potential effectiveness as anthropological markers. All three RFLPs were in Hardy-Weinberg equilibrium. The comparisons between present data on two of the major human groups and those on Europeans and Amerindians show a considerable heterogeneity for each of the three RFLPs under study. EcoRI, in particular, appears to be highly effective in distinguishing Africans, Europeans, and Asians from each other. As expected, the analysis at the haplotype level considerably improves the discriminating efficiency of these three markers by creating a clear-cut distinction between Tharus and Indonesians, the two Asian populations of the present survey. In fact, even though these two populations exhibit the same frequencies for the RsaI and MspI alleles, the frequency of the MspI(-) allele among the RsaI(-) chromosomes is 0.5 +/- 0.14 in the Indonesian sample and 0 + 0.04 in the Tharu sample.

Base Sequence↗
PubMed1994

COL1A2 gene (alpha 2 gene of type I collagen) at the haplotype level as a new valuable anthropogenetic marker: a study on Sardinians.

Sardinians, a population with many distinct anthropogenetic features, has been studied for the COLIA1 and COLIA2 genes at the DNA level for two purposes: to look for new RFLPs (restriction fragment length polymorphisms) and to study the distribution of three known COLIA2 RFLPs (EcoRI, RsaI, MspI) at both the allele and the haplotype levels. None of the eleven enzyme-probe systems examined led to the discovery of a new polymorphism. The following frequency q was found for the less common allele of the three RFLPs: EcoRI, q(+) = 0.178 +/- 0.031; RsaI, q(-) = 0.316 +/- 0.038; MspI, q(-) = 0.046 +/- 0.017. EcoRI turned out to be the most discriminant of the three polymorphisms because the frequency of the (+) allele in Sardinians was about half that estimated for a large homogeneous white sample (0.18 +/- 0.03 vs. 0.30 +/- 0.01). So far as the haplotype level is concerned, the sample is made up of triplets (parents and child). Therefore all the haplotype frequencies and delta values (degrees of disequilibrium, D) were obtained by direct counting of the unambiguously identified haplotypes rather than being based on their maximum-likelihood estimates. This together with their analytical and detailed presentation makes these data comparable with future findings, provided that the two data sets are presented in a comparable way. At this level the three RFLPs are efficient in distinguishing Sardinians from Calabrians (southern Italy) but not from the central Italian population. The present results, besides adding a further discriminative criterion between Sardinians and Italians (and whites on the whole), identify the complex COLIA2 locus as a valuable anthropogenetic marker.

Anthropology, Physical↗
PubMed1993

The common, Near-Eastern origin of Ashkenazi and Sephardi Jews supported by Y-chromosome similarity.

About 80 Sephardim, 80 Ashkenazim and 100 Czechoslovaks were examined for the Y-specific RFLPs revealed by the probes p12f2 and p49a,f on TaqI DNA digests. The aim of the study was to investigate the origin of the Ashkenazi gene pool through the analysis of markers which, having an exclusively holoandric transmission, are useful to estimate paternal gene flow. The comparison of the two groups of Jews with each other and with Czechoslovaks (which have been taken as a representative source of foreign Y-chromosomes for Ashkenazim) shows a great similarity between Sephardim and Ashkenazim who are very different from Czechoslovaks. On the other hand both groups of Jews appear to be closely related to Lebanese. A preliminary evaluation suggests that the contribution of foreign males to the Ashkenazi gene pool has been very low (1% or less per generation).

Adult↗
PubMed1993

COII/tRNA(Lys) intergenic 9-bp deletion and other mtDNA markers clearly reveal that the Tharus (southern Nepal) have Oriental affinities.

We searched for the East Asian mtDNA 9-bp deletion in the intergenic COII/tRNA(Lys) region in a sample of 107 Tharus (50 from central Terai and 57 from eastern Terai), a population whose anthropological origin has yet to be completely clarified. The deletion, detected by electrophoresis of the PCR-amplified nt 7392-8628 mtDNA fragment after digestion with HaeIII, was found in about 8% of both Tharu groups but was found in none of the 76 Hindus who were examined as a non-Oriental neighboring control population. A complete triplication of the 9-bp unit, the second case so far reported, was also observed in one eastern Tharu. All the mtDNAs with the deletion, and that with the triplication, were further characterized (by PCR amplification of the relevant mtDNA fragments and their digestion with the appropriate enzymes) to locate them in the Ballinger et al. phylogeny of East Asian mtDNA haplotypes. The deletion was found to be associated with four different haplotypes, two of which are reported for the first time. One of the deletions and especially the triplication could be best explained by the assumption of novel length-change events. Ballinger's classification of East Asian mtDNA haplotypes is mainly based on the phenotypes for the DdeI site at nt 10394 and the AluI site at nt 10397. Analysis of the entire Tharu sample revealed that more than 70% of the Tharus have both sites, the association of which has been suggested as an ancient East Asian peculiarity. These results conclusively indicate that the Tharus have a predominantly maternal Oriental ancestry. Moreover, they show at least one and perhaps two further distinct length mutations, and this suggests that the examined region is a hot spot of rearrangements.

Asian People↗
PubMed1992

MtDNA polymorphisms among Tharus of eastern Terai (Nepal).

Tharus--a population of Terai (a region with a severe malarial morbidity in the past)--can be subdivided into three main groups: Western, Central and Southern Tharus. They have usually been considered a Mongoloid population and this has been further substantiated by mtDNA findings on Central Tharus. Studies on the distribution of malaria-related genes have shown an extremely high frequency (0.8) of the alpha-thal gene among Western and Central Tharus. This frequency, however, unexpectedly turned out to be only 0.04 in a sample of Eastern Tharus. This raised doubts on the common notion that Tharus are a single anthropological entity. In the present investigation mtDNA markers were studied in the same sample of Eastern Tharus previously examined for the alpha-thal gene. The findings were: 1. the same three features which confirmed the classification of Central Tharus as Mongoloids (i.e., the common occurrence of HpaI-1/HincII-1 and HaeII-5 morphs, and the lack of BamHI polymorphism) were also present in this sample. Since the only neighbouring population accessible to Tharus, until recently, has been Hindu (Caucasoids), this result strongly supports the notion that Tharus are indeed a single anthropological entity; 2. two statistically significant differences between Eastern and Central Tharus--namely, a much higher HaeII morph 5 frequency among Central Tharus, and the absence in the same group of the mutation at 15.487 bp (very common among Eastern Tharus)--together with the results on alpha-tal gene, suggested that Tharu subgroups underwent an effective reproductive isolation.

Blotting, Southern↗
PubMed1991

A further polymorphism of the Gd locus for glucose-6-phosphate dehydrogenase present among blacks (Nigerians) and apparently absent among Caucasoids: the quantitative isoelectrophoretic variation of the Gd+ allele.

A structural but isoelectrophoretic moderate variation of glucose-6-phosphate dehydrogenase (G6PD) activity is common among Nigerians (a black population exposed to a long-lasting intense Plasmodium falciparum malarial endemia). It had never even been searched for among Caucasoids and Mongoloids. In the present work, we attempted to ascertain whether this polymorphism exists among Caucasoids. With this purpose, two Caucasoid male populations were studied: Sardinians and Romans, who respectively did and did not experience an evolutionarily effective exposure to P. falciparum. The approach adopted here consisted in comparing the variations of G6PD activity observed between brothers who certainly received their Gd gene from the same grandparent (hence Gd genes identical by descent) with those between brothers who received it (in the Roman series) or may have received it (in the Sardinian series) from different grandparents. No evidence for common moderate G6PD activity variations segregating with the Gd gene was found either in Romans or Sardinians, who have both been studied with much larger samples and more sensitive approaches than those which detected such type of polymorphism among Nigerians. The upper 95% confidence limit of such zero estimates for the frequency of the isoelectrophoretic quantitative Gd variant alleles were about 0.04 and 0.025 for Romans and Sardinians, respectively. This is the first example of a genetic region (the Gd gene with its flanking sequences) apparently monomorphic in a major race and with several (four) polymorphic sites in another major race.

Adolescent↗
PubMed1991

A survey of six genetic markers on the populations of Punjab and Rajasthan (India).

190 Punjabis (Hindus and Sikhs) of Chandigarh and 152 Hindus of Jodhpur (Rajasthan) were examined for six genetic markers, four of which (APO C-II, C6, C7 and FXIIIA) were not studied before in Asiatic Indians. For APO C-II and C7 only the common phenotype was found in a total of 229 and 99 subjects, respectively. For the remaining four markers the two samples were pooled since the gene frequency estimates were not significantly different: FXIIIA*2 = 0.205 +/- 0.016; C6*B = 0.366 +/- 0.037; PGM1*2 = 0.247 +/- 0.017; PGD*C = 0.041 +/- 0.008. These data may contribute to evaluate the extent of the Mongoloid genetic admixture into the Caucasoid gene pool of the Punjab and Rajasthan Hindu population.

Apolipoprotein C-II↗
PubMed1991

Protection against malaria morbidity: near-fixation of the alpha-thalassemia gene in a Nepalese population.

We have previously reported that the Tharu people of the Terai region in southern Nepal have an incidence of malaria about sevenfold lower than that of synpatric non-Tharu people. In order to find out whether this marked resistance against malaria has a genetic basis, we have now determined in these populations the prevalence of candidate protective genes and have performed in-vitro cultures of Plasmodium falciparum in both Tharu and non-Tharu red cells. We have found significant but relatively low and variable frequencies of beta-thal, beta S, G6PD (-), and Duffy (a-b-) in different parts of the Terai region. The average in-vitro rate of invasion and of parasite multiplication did not differ significantly in red cells from Tharus versus those from non-Tharu controls. By contrast, the frequency of alpha-thalassemia is uniformly high in Tharus, with the majority of them having the homozygous alpha-/alpha-genotype and an overall alpha-thal gene (alpha-) frequency of .8. We suggest that holoendemic malaria has caused preferential survival of subjects with alpha-thal and that this genetic factor has enabled the Tharus as a population to survive for centuries in a malaria-holoendemic area. From our data we estimate that the alpha-thal homozygous state decreases morbidity from malaria by about 10-fold. This is an example of selection evolution toward fixation of an otherwise abnormal gene.

Animals↗
PubMed1990

Studies on four restriction fragment length polymorphisms of the type I collagen genes in two Italian populations.

Type I collagen, the most abundant of the collagen protein family, is encoded by two genes, COL1A1 and COL1A2. Two random population samples, one from central Italy and one from southern Italy, were studied for 1 restriction fragment length polymorphism (RFLP) of COL1A1 (RsaI) and 3 RFLPs of COL1A2 (EcoRI, RsaI and MspI). A considerable heterogeneity for COL1A1/RsaI was found not only between Italians and English but even among Italians. The potential usefulness of these RFLPs and haplotypes as anthropogenetic markers, particularly in distinguishing Caucasoids from Negroids, has been discussed.

Asian People↗
PubMed1990

Population genetic studies on Jews. I. The alpha 2HS serum glycoprotein, a polymorphism strongly correlated with latitude.

A sample of Jews subdivided according to the birth-place of their parents or grand-parents have been examined for a large number of genetic markers in the course of a long-term project on the genetics of Jews. We report here the findings concerning 794 Jews studied for the AHSG polymorphism. All the subsamples were in Hardy-Weinberg equilibrium. A highly significant difference was found between Sephardic + Near East Jews and Ashkenazi (AHSG*2 frequencies: 0.184 +/- 0.015 and 0.258 +/- 0.016, respectively). For comparative purposes the data available on Caucasoids have been considered. It turned out that they were neatly arranged along a latitude-AHSG gene frequency cline (0.0092 of AHSG*2 gene frequency increase per degree of increase of latitude) in the explored 30 degrees-60 degrees range (r = 0.97; P much less than 0.001). Of the two Jewish frequencies that could be taken into consideration because of their sufficient sizes, that of the Near East + Sephardic Jews was perfectly in line with the above mentioned cline, while that of the Ashkenazi was somewhat displaced in the sense of being more similar than expected to the other, more southern, Jewish group. Since the only AHSG*2 frequency significantly displaced from the regression line is that of the Ashkenazi, whose ancestors lived until centuries ago in more southern areas, this finding is a strong confirmation of the observed cline.

Africa↗
PubMed1988

Decreased malaria morbidity in the Tharu people compared to sympatric populations in Nepal.

The Terai region of Nepal has been known to be heavily malarious since remote times, and it has, therefore, been regarded as uninhabitable by most Nepalese people. The Tharu people, who have been living in the Terai for centuries, were reputed to have an innate resistance to malaria. Following successful control of malaria by the Nepal Malaria Eradication Organization (NMEO), a large and heterogeneous non-Tharu population now inhabits the Terai along with Tharus. By analysing NMEO records, we have found that the prevalence of cases of residual malaria is nearly seven times lower among Tharus compared to sympatric non-Tharus. This difference applies to Plasmodium vivax, which is now much more common, and to Plasmodium falciparum. We suggest that the basis for resistance to malaria in the Tharu people is a genetic factor yet to be identified.

Adolescent↗
PubMed1986

Colour blindness distribution in the male population of Rome.

A total of 3,285 young males selected at random from the school population of Rome have been administered the Ishihara plates for colour blindness. Those who failed to read all plates correctly were further administered Farnsworth's Panel D-15 and the diagnoses of colour blindness were made by an ophthalmologist and cross checked. A total of 201 subjects were found to be colour-blind, allowing a gene frequency estimate of 0.061 +/- 0.004. This is the first reliable estimate for the Italian population and appears to be lower than for other Caucasoid populations. The gene frequency of colour blindness is known to increase from 0.02-0.04 in 'primitive' populations to 0.07-0.09 in Caucasoid populations, possibly as a result of a selection relaxation.

Adolescent↗