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Post by vgambler33 on Jan 10, 2006 15:16:20 GMT -5
Genetic admixture in three Mexican Mestizo populations based on D1S80 and HLA-DQA1 loci.
Cerda-Flores RM, Villalobos-Torres MC, Barrera-Saldana HA, Cortes-Prieto LM, Barajas LO, Rivas F, Carracedo A, Zhong Y, Barton SA, Chakraborty R.
Departamento de Genetica de Poblaciones, Centro de Investigacion Biomedica del Noreste (CIBIN), Instituto Mexicano del Seguro Social, Monterrey, Nuevo Leon, Mexico.
This study compares genetic polymorphisms at the D1S80 and HLA-DQA1 loci in three Mexican Mestizo populations from three large states (Nuevo Leon, Jalisco, and the Federal District). Allele frequency distributions are relatively homogenous in the three samples; only the Federal District population shows minor differences of the HLA-DQA1 allele frequencies compared with the other two. In terms of genetic composition, these Mestizo populations show evidence of admixture with predominantly Spanish-European (50-60%) and Amerindian (37-49%) contributions; the African contribution (1-3%) is minor. Together with the observation that in Nuevo Leon, the admixture estimates based on D1S80 and HLA-DQA1, are virtually the same as those reported earlier from blood group loci, suggests that DNA markers, such as D1S80 and HLA-DQA1 are useful for examining genetic homogeneity/heterogeneity across Mestizo populations of Mexico. The inverse relationship of the proportion of gene diversity due to population differences (Gst) to within population gene diversity (Hs) is also consistent with theoretical predictions, supporting the use of these markers for population genetics studies.
PMID: 11891937 [PubMed - indexed for MEDLINE]
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Post by vgambler33 on Jan 10, 2006 15:16:40 GMT -5
Genetic structure of the populations migrating from San Luis Potosi and Zacatecas to Nuevo Leon in Mexico.
Cerda-Flores RM, Kshatriya GK, Barton SA, Leal-Garza CH, Garza-Chapa R, Schull WJ, Chakraborty R.
Subjefatura de Investigacion Cientifica, Instituto Mexicano del Seguro Social, Nuevo Leon, Mexico.
The Mexicans residing in the Monterrey metropolitan area in Nuevo Leon, Mexico, were grouped by generation and birthplace [Monterrey Metropolitan Area (MMA), San Luis Potosi (SLP), and Zacatecas (ZAC)] of the four grandparents to determine the extent of genetic variation within this population and the genetic differences, if any, between the natives living in the MMA and the immigrant populations from SLP and ZAC. Nine genetic marker systems were analyzed. The genetic distance analysis indicates that SLP and ZAC are similar to the MMA, irrespective of birthplace and generation. Gene diversity analysis (GST) suggests that more than 96% of the total gene diversity (HT) can be attributed to individual variation within the population. The genetic admixture analysis suggests that the Mexicans of the MMA, SLP, and ZAC, stratified by birthplace and generation, have received a predominantly Spanish contribution (78.5%), followed by a Mexican Indian contribution (21.5%). Similarly, admixture analysis, conducted on the population of Nuevo Leon and stratified by generation, indicates a substantial contribution from the MMA (64.6%), followed by ZAC (22.1%) and SLP (13.3%). Finally, we demonstrate that there is no nonrandom association of alleles among the genetic marker systems (i.e., no evidence of gametic disequilibrium) despite the Mestizo origin of this population.
PMID: 2055589 [PubMed - indexed for MEDLINE]
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Post by vgambler33 on Jan 10, 2006 15:16:59 GMT -5
Genetic variation in Arizona Mexican Americans: estimation and interpretation of admixture proportions.
Long JC, Williams RC, McAuley JE, Medis R, Partel R, Tregellas WM, South SF, Rea AE, McCormick SB, Iwaniec U.
Department of Anthropology, University of New Mexico, Albuquerque 87131.
Mexican Americans are a numerous and fast growing ethnic population in the United States. Yet little is known about their genetic structure. Since they are a hybrid, it is of interest to identify their parental populations and to estimate the relative contributions of these groups. This information is relevant to historical, biomedical, and evolutionary concerns. New genetic typings on 730 Arizona Mexican Americans for the HLA-A, HLA-B, ABO, Rh, MNSs, Duffy, Kidd, and Kell loci are presented here and they are used to estimate ancestral contributions. We considered both a dihybrid model with Amerindians and Spaniards as proposed ancestors, and a trihybrid model with Amerindians, Spaniards, and Africans as proposed ancestors. A modified weighted least squares method that allows for linkage disequilibrium was used to estimate ancestral contributions for each model. The following admixture estimates were obtained: Amerindian, 0.29 +/- 0.04; Spaniard, 0.68 +/- 0.05; and African, 0.03 +/- 0.02. The interpretation of these results with respect to Amerindian and Spanish ancestry is straightforward. African ancestry is strongly supported by the presence of a marker of African descent, Fy, despite the fact that the standard error of the estimate is as large as the estimated admixture proportion. An evaluation of the sensitivity of these results to a number of variables is presented: 1) our choices of ancestral allele frequencies, 2) the possibility of selection at HLA and the blood groups, and 3) genetic drift in Mexican Americans.
PMID: 2021190 [PubMed - indexed for MEDLINE]
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Post by vgambler33 on Jan 10, 2006 15:17:19 GMT -5
Gene diversity and estimation of genetic admixture among Mexican-Americans of Starr County, Texas.
Cerda-Flores RM, Kshatriya GK, Bertin TK, Hewett-Emmett D, Hanis CL, Chakraborty R.
Subjefatura de Investigacion Cientifica, IMMS, Unidad de Investigacion Biomedica del Noreste, Monterrey, Nuevo Leon, Mexico.
The Mexican-Americans of Starr County, Texas, classified by sex and birthplace, were studied to determine the extent of genetic variation and contributions from ancestral populations such as Spanish,and Amerindian . Using 21 genetic marker systems, genetic distance and diversity analyses indicate that subpopulations of Mexican-Americans in Starr County are similar, and that more than 99% of the total gene diversity (HT) can be attributed to individual variation within the population. Genetic admixture analysis shows the predominant influence comes from the Spanish, a lesser contribution from Amerindians . The contribution of the ancestral population to various subpopulations of the Mexican-Americans of Starr County is similar. The Mexican-Americans of Starr County are similar to the Mexican population from northeastern Mexico. The history of admixture is apparently old enough to have brought the entire Mexican-American gene pool to Hardy-Weinberg equilibrium. There is no non-random association of alleles among the genetic marker systems considered in the present study, in spite of the fact that this population is of admixed origin. These results, in aggregate, suggest genetic homogeneity of the Mexican-Americans of Starr County, Texas, and point towards the utility of this population for genetic and epidemiological studies.
PMID: 1616290 [PubMed - indexed for MEDLINE]
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Post by vgambler33 on Jan 10, 2006 15:17:46 GMT -5
LOOK the Mexican-American genetic make up is no different from the genetic make up of other Mexican-Americans example Texas.
Polymorphic gene markers in Mexican-Americans residing in southern California.
Shohat T, Shaw SJ, Sparkes RS, Vadheim CM, Rotter JI, Zeidler A.
Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, Calif., USA.
The gene frequencies of nine different genetic polymorphic markers [ABO, MNS and P blood groups; haptoglobin, transferrin, Gc protein, complement (C3), properdin factor B and alpha 1-antitrypsin] were determined in 94 Mexican-Americans residing in the Los Angeles, California area. Comparisons with published data on Mexican-Americans living in other areas of the United States or in Mexico itself revealed no significant differences in the gene frequencies between this and previous studies. However, data from the current study demonstrated significant differences in ABO and haptoglobin allele frequencies compared to published non-Hispanic Caucasian data. These data suggest a large degree of genetic homogeneity in the Mexican-American population residing in the United States.
PMID: 7615300 [PubMed - indexed for MEDLINE]
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Post by vgambler33 on Jan 10, 2006 15:18:11 GMT -5
44% IBERIAN GENES IN THE HEART OF AZTEC COUNTRY (MEXICO CITY)
Gene frequencies and admixture estimates in a Mexico City population.
Lisker R, Perez-Briceno R, Granados J, Babinsky V, de Rubens J, Armendares S, Buentello L.
Five hundred and ten students of the Universidad Nacional Autonoma de Mexico were tested to determine the distribution of ABO, MN, Rr-Hr blood groups, and serum haptoglobin, albumin, and Factor Bf types. Based on the results we found that the proportion of Indian and White genes are of 56.16 and 43.84%, respectively in the dihybrid model and 2.93, 56.22, and 40.85% for Blacks, Indians, and Whites in the trihybrid one. The present study reveals a higher proportion of Indian genes in the Mexico City population than estimated in previous publications. Reasons why the present results apply to a much larger group of Mexico City mestizos than the previous ones are given.
PMID: 3099584 [PubMed - indexed for MEDLINE]
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Post by vgambler33 on Jan 10, 2006 15:18:45 GMT -5
Gene frequencies and racial intermixture in a Mestizo population from Mexico City.
Tiburcio V, Romero A, De Garay AL.
Blood specimens from a sample (of some 460 subjects) from the Mestizo population in Mexico City were tested for haptoglobin, transferrin, glucose-6-phosphate dehydrogenase, acid phosphatase and haemoglobin types and blood groups. Gene frequencies for these characters were estimated. From the data on O, M, N, S, R degrees, r, Pc frequencies, the amount of admixture was calculated. In the Mestizo population studied the major contribution comes from European sources and the secondary contributions from Mexican Indians; the contribution from African sources is minimal.
PMID: 655624 [PubMed - indexed for MEDLINE]
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Post by vgambler33 on Jan 10, 2006 15:19:17 GMT -5
Genetic structure of autochthonous populations of Meso-America: Mexico.12
Lisker R, Ramirez E, Babinsky V.
Departamento de Genetica, Instituto Nacional de la Nutricion Salvador Zubiran, Mexico City, Mexico.
We analyze the possible effect of gene flow on the genetic structure of present-day Mexicans. For this purpose we reviewed previous admixture estimates for various Indian groups. Several facts seem clear: There are no pure Indian groups in Mexico, because all Indian groups show variable degrees of admixture, mostly with whites (range, 0.088 in the Huichol to 0.373 in the Huasteco).
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Post by vgambler33 on Jan 10, 2006 15:19:38 GMT -5
The genetic structure of Mexican Mestizos of different locations: tracking back their origins through MHC genes, blood group systems, and microsatellites.
Gorodezky C, Alaez C, Vazquez-Garcia MN, de la Rosa G, Infante E, Balladares S, Toribio R, Perez-Luque E, Munoz L.
Department of Immunogenetics, Instituto de Diagnostico y Referencia Epidemiologicos, (InDRE), SSA, Mexico City, Mexico. cgorodea@mailer.main.conacyt.mx
Mexican Mestizos, who are the result of the admixture of Spanish, Indian, and Black genes, were analyzed for different systems. Three populations from geographical distinct areas were studied: the north (State of Nuevo Leon ), the center (State of Guanajuato), and the highlands (mainly Mexico City). Ten blood group systems (N = 229), STRs (N = 107), HLA-A*, B*, C* (N = 116-167), and DRB1, DQA1, and DQB1 (N = 40, 101, 160, respectively) were analyzed in the samples of the highlands. The three groups cluster together in the same branch: Mestizos from Venezuela, Mediterranean and Jews close to the cluster of Orientals, followed by Amerindians. All markers demonstrate that Indian genes are strongly represented in the highlands: Di(a), O, D(-)(+), s, A*0201, *0206, B*1539 (*1541), *3902, *3905, *3512, *3517, *4002, *4005, Cw*0801, *0304, *0401 among others. Cw*0501, *1203, *1204, and *1601 are of White ancestry. The most frequent haplotypes *0407-*03011-*0302 and *0802-*0401-*0402 are of Indian descent as well. The center and mainly the north show a more Caucasian and Semitic profile. The results demonstrate the high variability resulting from interethnic admixture, suggesting that this mechanism is the main factor responsible for the large diversity found in urban populations.
PMID: 11543900 [PubMed - indexed for MEDLINE]
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Post by vgambler33 on Jan 10, 2006 15:19:55 GMT -5
Dental variation among four prehispanic Mexican populations.
Haydenblit R.
Department of Biological Anthropology, University of Cambridge, United Kingdom.
In this paper, the dental morphology of prehispanic Meso-american populations is described, compared, and examined within the context of New World dental variation. Twenty-eight morphological dental traits were studied and compared in four samples of prehispanic Mexican populations. After eliminating intra- and interobserver error, the dental morphological characteristics observed show evidence of heterogeneity among the populations. In particular, the oldest population, Tlatilco (1300-800 BC), was significantly different from the other three groups, Cuicuilco (800-100 BC), Monte Alban (500 BC-700 AD) and Cholula (550-750 AD). When the four samples were compared to other Mongoloid populations, either univariately or multivariately, it was observed that the Mexican groups did not follow a strict Sinodont (characteristic of Northeast Asia)/Sundadont (characteristic of Southeast Asia) classification (Turner [1979] Am. J. Phys. Anthropol. 51:619-636). From the traits examined, 27% presented frequencies consistent with Sinodont variation, while 73% of the traits showed similar incidence to Southeast Asian groups. Multivariately, the Mexican populations were found to fit an overall Sundadont classification. These results indicate that there is more dental morphological variation among American Indian populations than previously shown.
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Post by vgambler33 on Jan 10, 2006 15:20:16 GMT -5
Distribution of paraoxonase PON1 gene polymorphisms in Mexican populations. Its role in the lipid profile.
Gamboa R, Zamora J, Rodriguez-Perez JM, Fragoso JM, Cardoso G, Posadas-Romero C, Vargas-Alarcon G.
Department of Physiology and Grupo de Estudio en Genomica y Proteomica de Enfermedades Cardiovasculares, Instituto Nacional de Cardiologia "Ignacio Chavez" Juan Badiano No. 1, Tlalpan 14080, Mexico City, Mexico.
Paraoxonase gene polymorphisms (PON1-55 and PON1-192) were determined in four Mexican populations (Mestizos, Nahuas, Teenek and Mayos) belonging to different ethnic groups. The role of these polymorphisms in the lipid profile in the Mestizo group was also analyzed. PON1 polymorphisms were determined by polymerase chain reaction-restriction fragment length polymorphism. Comparison among Mexican populations showed increased frequencies of PON1-55 L allele and LL genotype and decreased frequencies of M allele and LM genotype in the three Amerindian populations when compared to Mestizos (P < 0.05). Mexicans together with Asian populations (from Japan and China) presented the highest frequencies of PON1-55 L allele (P < 0.05 when compared to Caucasian populations). Heterogeneous data were noted when PON1-192 polymorphism comparison was made. In summary, distribution frequencies of PON1 showed that Mexican populations are more related to Asians than Caucasians. This confirms previous studies with other genetic markers indicating that Native Americans have stronger genetic affinities to the Paleolithic people of North-East Asia than to other major world populations. In Mexican Mestizos, lack of correlation between PON1 polymorphisms and lipid profile was found, corroborating previous data in other populations. The present data could be helpful to understand the distribution of these polymorphisms and its role as genetic and evolutive markers in the Amerindian populations.
PMID: 15993880 [PubMed - in process]
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Post by vgambler33 on Jan 10, 2006 15:23:29 GMT -5
Natural fertility in northeastern Mexico: genetic structure by year of birth and birthplace.
Cerda-Flores RM, Davila-Rodriguez MI.
Departamento de Genetica de Poblaciones, Centro de Investigacion Biomedica del Noreste, Instituto Mexicano del Seguro Social, Monterrey, Nuevo Leon, Mexico. ricardocerda@hotmail.com
BACKGROUND: The aims of this population genetics study were 1) to ascertain whether 417 Mexican women with natural fertility (45 years of age, married, not using any family planning methods, residing in the state of Nuevo Leon) were genetically homogeneous, and 2) to compare the genetic structure of this selected population with the previously reported data of random populations of northeastern Mexico. METHODS: A sample of 417 women was interviewed and selected in seven medical units of the Mexican Social Security Institute. They were grouped by their year of birth (1896-1925 and 1926-1955) and birthplace [persons whose four grandparents were born in the northeastern states (NE) and outside the northeastern states (Not-NE) of Mexico]. Eight genetic marker systems were analyzed. RESULTS: Gene diversity analysis suggests that more than 99.1% of the total gene diversity can be attributed to variation between individuals within the population. Genetic admixture analysis suggests that this selected population, stratified by year of birth and birthplace, have received a predominantly Spanish contribution followed by a lesser Mexican Indian contribution. CONCLUSIONS: The genetic structure of this selected population was homogeneous and similar to the random populations of northeastern Mexico. This finding corroborates the utility of this selected population for genetic and epidemiological studies.
PMID: 11179589 [PubMed - indexed for MEDLINE]
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Post by vgambler33 on Jan 10, 2006 15:25:30 GMT -5
Genetic structure of seven Mexican indigenous populations based on five polymarker loci.
Buentello-Malo L, Penaloza-Espinosa RI, Loeza F, Salamanca-Gomez F, Cerda-Flores RM.
Instituto de Investigaciones Antropologicas, Universidad Nacional Autonoma de Mexico, Mexico DF.
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 (H(T)) 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. Copyright 2002 Wiley-Liss, Inc.
PMID: 12552575 [PubMed - indexed for MEDLINE]
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Post by eufrenio on Jan 10, 2006 15:25:49 GMT -5
If it´s only 44% in the student population, shouldn´t it be even lower among the general population?
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Post by vgambler33 on Jan 10, 2006 15:26:23 GMT -5
Molecular heterogeneity of glucose-6-phosphate dehydrogenase deficiency in Mexico: overall results of a 7-year project.
Vaca G, Arambula E, Esparza A.
Division de Genetica, Centro de Investigacion Biomedica de Occidente, Instituto Mexicano del Seguro Social (IMSS), Guadalajara, Jalisco, Mexico. gvacap@yahoo.com
Several years ago, a project aiming to determine (i) the molecular basis of G-6-PD deficiency, (ii) the distribution of four different mutant alleles previously detected, and (iii) the whole of polymorphic alleles that account for the overall prevalence of G-6-PD deficiency in Mexico was implemented. Nearly 5000 individuals-from the general population and patients with hemolytic anemia-belonging to at least 14 States were screened for G-6-PD deficiency. Seventy-six G-6-PD-deficient subjects were detected and the prevalence of G-6-PD deficiency in 4777 individuals from the general population was 0.71%. Screening for both mutations associated with enzyme deficiency and silent polymorphisms at the G-6-PD gene was performed in the enzyme-deficient individuals by PCR-SSCP combined with restriction enzyme analysis; the silent polymorphisms as well as the nondeficient variant G-6-PD A(376G) were also investigated in 366 G-6-PD normal individuals from the general population. In 88% of the enzyme-deficient individuals it was possible to define the mutation responsible and the type G-6-PD A- variants were the more common in both individuals from the general population and patients with hemolytic anemia. G-6-PD deficiency is heterogeneous at the DNA level in Mexico and up to date 10 different variants-8 in the present project and 2 previously-have been observed: G-6-PD A(-202A/376G), G-6-PD A(-376G/968C), G-6-PD Santamaria(376G/542T), G-6-PD Vanua Lava(383C), G-6-PD Tsukui(del561-563), G-6-PD "Mexico City"(680A), G-6-PD Seattle(844C), G-6PD Guadalajara(1159T),G-6-PD Nashville(1178A), and G-6-PD Union(1360T). The G-6-PD A(-) variants have a relatively homogeneous distribution and along with G-6-PD Santamaria(376G/542T), they account for 82% of the overall prevalence of G-6-PD deficiency in Mexico; all other seven variants represent 9% of the mutant alleles examined, and in the rest of the chromosomes the mutation responsible for the enzyme deficiency remains to be defined. Several of the variants observed in Mexico are common in Africa, South Europe, and Southeast Asia. The prevalence for the variant G-6-PD A(376G) was 1.64%. From 256 possible haplotypes only 14 were observed and haplotype analysis suggests that some of the G-6-PD variants probably were imported to Mexico by population flow from South Europe, Africa, and Southeast Asia. This work (i) identified the G-6-PD variants prevalent in Mexico, (ii) defines their geographical distribution, (iii) contributes to the knowledge of the genetic structure of the Mexican population, and (iv) will facilitate the molecular analysis of the G-6-PD gene in enzyme-deficient Mexican individuals.
PMID: 12367588 [PubMed - indexed for MEDLINE]
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