Association between C1q gene polymorphisms and autoimmune thyroid diseases

ABSTRACT Objective In the present study, we aimed to assess the associations of C1q gene polymorphisms with autoimmune thyroid diseases (AITD) susceptibility. Subjects and methods A set of 1,003 AITD patients (661 with Graves' disease and 342 with Hashimoto's thyroiditis) and 880 ethnically- and geographically-matched controls from Chinese Han population were included. Five common single nucleotide polymorphisms (SNPs) (rs294185, rs292001, rs682658, rs665691 and rs294179) in C1q gene locus were genotyped. Frequencies of genotypes and alleles were compared between patients and controls, and haplotype analysis was also performed. Results There was no statistically significant difference between AITD patients and controls in the frequencies of alleles of rs294185 (P = 0.41), rs292001 (P = 0.71), rs682658 (P = 0.68), rs665691 (P = 0.68) and rs294179 (P = 0.69). There was also no statistically significant difference between AITD patients and controls in the frequencies of genotypes of rs294185 (P = 0.72), rs292001 (P = 0.89), rs682658 (P = 0.83), rs665691 (P = 0.90) and rs294179 (P = 0.43). Stratified analyses showed that none of those five SNPs in C1q gene were associated with Graves' disease or Hashimoto's thyroiditis (all P values > 0.05). Haplotype analysis revealed that there were no obvious genetic associations of C1q gene polymorphisms with AITD susceptibility. Conclusions We, for the first time, identified the associations between C1q gene SNPs and AITD, and our findings suggested that five common SNPs in C1q gene were not associated with AITD susceptibility in Chinese Han population.

Linkage disequilibrium and mutation rate analysis of sixteen X-STR loci / 法医学杂志

OBJECTIVE@#To assess the patterns of linkage disequilibrium (LD) of 16 STR loci on X chromo- some and investigate the genetic stability.@*METHODS@#Genomic DNA samples extracted from blood stains from 500 unrelated individuals and 885 lineage members from Eastern Chinese Han population were genotyped through multiplex amplification using IDtyperX-16 kit by our independent research followed by capillary electrophoresis. LD was assessed by PowerMarker v3.25 software and mutation rate of every locus was analyzed.@*RESULTS@#LD were not found at the 16 X-STR loci. Allele mutations were observed at 10 loci. Among them, mutation rates of DXS6809 and DXS7132 were both up to 0.0048.@*CONCLUSION@#When the 16 X-STR loci included in IDtyperX-16 kit were used for parentage testing, product princi- ples can be applied to calculate the likelihood, but mutation should be taken into consideration in the case that the genotypes do not meet the genetic law (especially at DXS6809 and DXS7132).

Comprehensive Variant Screening of the UGT Gene Family

PURPOSE: UGT1A1, UGT2B7, and UGT2B15 are well-known pharmacogenes that belong to the uridine diphosphate glucuronyltransferase gene family. For personalized drug treatment, it is important to study differences in the frequency of core markers across various ethnic groups. Accordingly, we screened single nucleotide polymorphisms (SNPs) of these three genes and analyzed differences in their frequency among five ethnic groups, as well as attempted to predict the function of novel SNPs. MATERIALS AND METHODS: We directly sequenced 288 subjects consisting of 96 Korean, 48 Japanese, 48 Han Chinese, 48 African American, and 48 European American subjects. Subsequently, we analyzed genetic variability, linkage disequilibrium (LD) structures and ethnic differences for each gene. We also conducted in silico analysis to predict the function of novel SNPs. RESULTS: A total of 87 SNPs were detected, with seven pharmacogenetic core SNPs and 31 novel SNPs. We observed that the frequencies of UGT1A1 *6 (rs4148323), UGT1A1 *60 (rs4124874), UGT1A1 *93 (rs10929302), UGT2B7 *2 (rs7439366), a part of UGT2B7 *3 (rs12233719), and UGT2B15 *2 (rs1902023) were different between Asian and other ethnic groups. Additional in silico analysis results showed that two novel promoter SNPs of UGT1A1 -690G>A and -689A>C were found to potentially change transcription factor binding sites. Moreover, 673G>A (UGT2B7), 2552T>C, and 23269C>T (both SNPs from UGT2B15) changed amino acid properties, which could cause structural deformation. CONCLUSION: Findings from the present study would be valuable for further studies on pharmacogenetic studies of personalized medicine and drug response.

MSX1 gene and nonsyndromic oral clefts in a Southern Brazilian population

Nonsyndromic oral clefts (NSOC) are the most common craniofacial birth defects in humans. The etiology of NSOC is complex, involving both genetic and environmental factors. Several genes that play a role in cellular proliferation, differentiation, and apoptosis have been associated with clefting. For example, variations in the homeobox gene family member MSX1, including a CA repeat located within its single intron, may play a role in clefting. The aim of this study was to investigate the association between MSX1 CA repeat polymorphism and NSOC in a Southern Brazilian population using a case-parent triad design. We studied 182 nuclear families with NSOC recruited from the Hospital de Clínicas de Porto Alegre in Southern Brazil. The polymorphic region was amplified by the polymerase chain reaction and analyzed by using an automated sequencer. Among the 182 families studied, four different alleles were observed, at frequencies of 0.057 (175 bp), 0.169 (173 bp), 0.096 (171 bp) and 0.67 (169 bp). A transmission disequilibrium test with a family-based association test (FBAT) software program was used for analysis. FBAT analysis showed overtransmission of the 169 bp allele in NSOC (P=0.0005). These results suggest that the CA repeat polymorphism of the MSX1 gene may play a role in risk of NSOC in populations from Southern Brazil.

Genetic polymorphisms of SNP loci in the 5' and 3' region of TPH2 gene in Northern Chinese Han population / 法医学杂志

OBJECTIVE@#To investigate the genetic polymorphism in the 5' and 3' region of TPH2 gene of Northern Chinese Han population and to explore its application value in forensic medicine.@*METHODS@#The sequence variants and the genetic polymorphisms of 6 SNP loci (rs4570625, rs11178997, rs11178998, rs41317118, rs17110747 and rs41317114) within a 905 bp 5' flanking region and a 1,104bp 3' flanking region of TPH2 gene were analyzed by DNA sequencing in a total of 244 unrelated healthy individuals in Northern Chinese Han population. The statistical analysis was carried out by Haploview v4.2 software.@*RESULTS@#The genotypic distributions of the 6 SNP loci in the TPH2 gene were in accordance with Hardy-Weinberg equilibrium. One C/T variant in 92922 site was found. There was a high linkage disequilibrium among the 3 SNP loci (rs4570625, rs11178997 and rs11178998) in the 5' region and the 3 SNP loci (rs41317118, rs17110747 and rs41317114) in the 3' region of TPH2 gene, respectively. The parameters of population genetics of 6 SNP loci were obtained.@*CONCLUSION@#There are great polymorphisms in the 5' and 3' region of TPH2 gene in Northern Chinese Han population, which could be used as genetic indexes for association analysis of the related diseases, as well as for forensic individual identification and paternity testing.

Genetic association of SNPs in the FTO gene and predisposition to obesity in Malaysian Malays

The common variants in the fat mass- and obesity-associated (FTO) gene have been previously found to be associated with obesity in various adult populations. The objective of the present study was to investigate whether the single nucleotide polymorphisms (SNPs) and linkage disequilibrium (LD) blocks in various regions of the FTO gene are associated with predisposition to obesity in Malaysian Malays. Thirty-one FTO SNPs were genotyped in 587 (158 obese and 429 non-obese) Malaysian Malay subjects. Obesity traits and lipid profiles were measured and single-marker association testing, LD testing, and haplotype association analysis were performed. LD analysis of the FTO SNPs revealed the presence of 57 regions with complete LD (D’ = 1.0). In addition, we detected the association of rs17817288 with low-density lipoprotein cholesterol. The FTO gene may therefore be involved in lipid metabolism in Malaysian Malays. Two haplotype blocks were present in this region of the FTO gene, but no particular haplotype was found to be significantly associated with an increased risk of obesity in Malaysian Malays.

Genetic association of the EGR2 gene with bipolar disorder in Korea

The early growth response gene 2 (EGR2) is located at chromosome 10q21, one of the susceptibility loci in bipolar disorder (BD). EGR2 is involved in cognitive function, myelination, and signal transduction related to neuregulin-ErbB receptor, Bcl-2 family proteins, and brain-derived neurotrophic factor. This study investigated the genetic association of the EGR2 gene with BD and schizophrenia (SPR) in Korea. In 946 subjects (350 healthy controls, 352 patients with BD, and 244 with SPR), nine single nucleotide polymorphisms (SNPs) in the EGR2 gene region were genotyped. Five SNPs showed nominally significant allelic associations with BD (rs2295814, rs61865882, rs10995315, rs2297488, and rs2297489), and the positive associations of all except rs2297488 remained significant after multiple testing correction. Linkage disequilibrium structure analysis revealed two haplotype blocks. Among the common identified haplotypes (frequency > 5%), 'T-G-A-C-T (block 1)' and 'A-A-G-C (block 2)' haplotypes were over-represented, while 'C-G-G-T-T (block 1)' haplotype was under-represented in BD. In contrast, no significant associations were found with SPR. Although an extended analysis with a larger sample size or independent replication is required, these findings suggest a genetic association of EGR2 with BD. Combined with a plausible biological function of EGR2, the EGR2 gene is a possible susceptibility gene in BD.

APOA1 gene polymorphisms in the South Asian immigrant population in the United States.

BACKGROUND: Coronary artery disease (CAD) is a leading cause of death in the United States. South Asian immigrants (SAIs) from the Indian subcontinent living in the US are disproportionately at higher risk of CAD than other immigrant populations. Unique genetic factors may predispose SAIs to increased risk of developing CAD when adopting a Western lifestyle including a higher-fat diet, more sedentary behavior and additional gene-environment interactions. SAIs are known to have low levels of the protective high density lipoprotein (HDL) and an altered function for Apo-lipoprotein A-1 (ApoA1), the main protein component of HDL cholesterol. One gene that may be genetically distinctive in this population is APOA1 which codes for ApoA-1 protein, a potentially important contributing factor in the development of CAD. MATERIALS AND METHODS: DNA sequencing was performed to determine the status of the seven single-nucleotide polymorphisms (SNPs) in the APOA1 gene from 94 unrelated SAI adults. Genotypes, allelic frequencies, and intragenic linkage disequilibrium of the APOA1 SNPs were calculated. RESULTS: Several polymorphisms and patterns were common among persons of south Asian ethnicity. Frequencies for SNPs T655C, T756C and T1001C were found to be different than those reported in European Caucasian individuals. Linkage disequilibrium was found to be present between most (13 of 15) SNP pairings indicating common inheritance patterns. CONCLUSIONS: SAIs showed variability in the sequence of the APOA1 gene and linkage disequilibrium for most SNPS. This pattern of APOA1 SNPs may contribute to decreased levels of HDL cholesterol reported in SAIs, leading to an increased risk for developing CAD in this population.

Power comparison between population-based case–control studies and family-based transmission–disequilibrium tests: An empirical study.

BACKGROUND: There are two major classes of genetic association analyses: population based and family based. Population-based case–control studies have been the method of choice due to the ease of data collection. However, population stratification is one of the major limitations of case–control studies, while family-based studies are protected against stratification. In this study, we carry out extensive simulations under different disease models (both Mendelian as well as complex) to evaluate the relative powers of the two approaches in detecting association. MATERIALS AND METHODS: The power comparisons are based on a case–control design comprising 200 cases and 200 controls versus a Transmission Disequilibrium Test (TDT) or Pedigree Disequilibrium Test (PDT) design with 200 informative trios. We perform the allele-level test for case–control studies, which is based on the difference of allele frequencies at a single nucleotide polymorphism (SNP) between unrelated cases and controls. The TDT and the PDT are based on preferential allelic transmissions at a SNP from heterozygous parents to the affected offspring. We considered five disease modes of inheritance: (i) recessive with complete penetrance (ii) dominant with complete penetrance and (iii), (iv) and (v) complex diseases with varying levels of penetrances and phenocopies. RESULTS: We find that while the TDT/PDT design with 200 informative trios is in general more powerful than a case–control design with 200 cases and 200 controls (except when the heterozygosity at the marker locus is high), it may be necessary to sample a very large number of trios to obtain the requisite number of informative families. CONCLUSION: The current study provides insights into power comparisons between population-based and family-based association studies.

Haplotype diversity and linkage disequilibrium at the DRD2 locus among the tribes of western and southern regions of India.

BACKGROUND: Dopamine receptor D2 (DRD2) is an important gene having functional significance in the fields of neuropsychiatry and pharmacology and also has importance in evolutionary studies. MATERIALS AND METHODS: This study was undertaken to find out the haplotype distribution and linkage disequilibrium (LD) pattern for the three TaqI sites (TaqI ‘A’, TaqI ‘B’ and TaqI ‘D’) in the DRD2 gene in 232 unrelated individuals from five ethno-linguistically distinct endogamous tribal populations; Siddis and Gonds of Uttara Kannada district, Karnataka; Varli and Kolgha of Valsad district, Gujarat; and Dangi Konkana of Dang district, Gujarat. The genotype data obtained after molecular analysis of the three DRD2 sites was subjected to statistical analysis such as calculation of allele frequencies, haplotype frequencies among others. Subsequently, a neighbor-joining tree was also constructed from the data obtained. RESULTS: The three DRD2 sites were found to be polymorphic in all the populations. All the populations showed high levels of heterozygosities. Out of the eight possible haplotypes, most populations shared seven haplotypes. Of all the populations, Siddis showed the highest frequency of the ancestral haplotype B2D2A1 (11.4%). Significant LD was found to exist for TaqI ‘A’ and TaqI ‘B’ sites in both the populations. CONCLUSION: The findings are in concurrence with those from other Indian studies, especially from Dravidian-speaking South Indian populations. Similar pattern of diversity observed for ethnically and linguistically diverse populations in the present study is indicative of complex structure of Indian populations.

Pharmacogenetic polymorphisms in Brazilian-born, first-generation Japanese descendants

Brazil hosts the largest Japanese community outside Japan, estimated at 1.5 million individuals, one third of whom are first-generation, Brazilian-born with native Japanese parents. This large community provides a unique opportunity for comparative studies of the distribution of pharmacogenetic polymorphisms in native Japanese versus their Brazilian-born descendants. Functional polymorphisms in genes that modulate drug disposition (CYP2C9, CYP2C19 and GSTM3) or response (VKORC1) and that differ significantly in frequency in native Japanese versus Brazilians with no Japanese ancestry were selected for the present study. Healthy subjects (200 native Japanese and 126 first-generation Japanese descendants) living in agricultural colonies were enrolled. Individual DNA was genotyped using RFLP (GSTM3*A/B) or TaqMan Detection System assays (CYP2C9*2 and *3; CYP2C19*2 and *3; VKORC1 3673G>A, 5808T>G, 6853G>C, and 9041G>A). No difference was detected in the frequency of these pharmacogenetic polymorphisms between native Japanese and first-generation Japanese descendants. In contrast, significant differences in the frequency of each polymorphism were observed between native or first-generation Japanese and Brazilians with no Japanese ancestry. The VKORC1 3673G>A, 6853G>C and 9041G>A single nucleotide polymorphisms were in linkage disequilibrium in both native and first-generation Japanese living in Brazil. The striking similarity in the frequency of clinically relevant pharmacogenetic polymorphisms between Brazilian-born Japanese descendants and native Japanese suggests that the former may be recruited for clinical trials designed to generate bridging data for the Japanese population in the context of the International Conference on Harmonization.

Utilizing linkage disequilibrium information from Indian Genome Variation Database for mapping mutations: SCA12 case study.

Stratification in heterogeneous populations poses an enormous challenge in linkage disequilibrium (LD) based identification of causal loci using surrogate markers. In this study, we demonstrate the enormous potential of endogamous Indian populations for mapping mutations in candidate genes using minimal SNPs, mainly due to larger regions of LD. We show this by a case study of the PPP2R2B gene (approximately 400 kb) that harbours a CAG repeat, expansion of which has been implicated in spinocerebellar ataxia type 12 (SCA12). Using LD information derived from Indian Genome Variation database (IGVdb) on populations which share similar ethnic and linguistic backgrounds as the SCA12 study population, we could map the causal loci using a minimal set of three SNPs, without the generation of additional basal data from the ethnically matched population. We could also demonstrate transferability of tagSNPs from a related HapMap population for mapping the mutation.

Analysis and application of haplotype in forensic medicine / 法医学杂志

Haplotype is a lineable combination of alleles at multiple loci that are transmitted together on chromosome or mitochondrion. In October 2002, the international HapMap project started and aimed at mapping the haplotype blocks of human being and discovering the Tag SNPs by determining the DNA sequence variation patterns, variation frequency and their relationship. This review summarizes the formation and distribution of the haplotype and the current three haplotype-analysis methods including the methodology of experiment, the deduction from pedigrees and the statistic method. When an allele linkage disequilibrium occurs, the genetic probability would be evaluated by haplotype. The importance of haplotype has been recognized and its application has been gradually increased in forensic sciences. The current focus on haplotype study in forensic science involves Chromosome Y, Mitochondrial DNA and Chromosome X, which are useful supplements of genetic marks.

Mapeamento genético do locus 1q 24.2 – 1q31.3 em famílias segregando periodontite agressiva / Genetic mapping of locus 1q 24.2 – 1q 3.3 in families segregating aggressive periodontitis

Um estudo sugere que o fenótipo da periodontite agressiva localizada está ligado a região 1q25. O objetivo do presente estudo foi aperfeiçoar o mapeamento genético da periodontite agressiva na região cromossômica supracitada em famílias clinicamente bem caracterizadas segregando a doença. A hipótese deste estudo é que variações genéticas localizadas no cromossomo 1 entre as regiões 1q 24.2 e 1q 31.3 contribuem para o fenótipo da periodontite agressiva. Como objetivos específicos, determinamos o modo de herança da periodontite agressiva através de análise de segregação, e verificamos a existência de ligação e/ou associação entre a região 1q 24.2-1q 31.3 e a periodontite agressiva. A análise de segregação foi executada no programa SEGREG do pacote SAGE versão 5.4.2 com base nos dados dos pedigrees das primeiras 74 famílias recrutadas neste estudo, totalizando 475 indivíduos (média de 6.4 indivíduos por família) de origem geográfica similar. Assumiu-se a herança Mendeliana como um locus autossômico com 2 alelos A e B, onde o alelo A estava associado ao fenótipo relevante. Cinco modos de transmissão (não homogêneo, Mendeliano homogêneo, homogêneo geral, semigeral, heterogêneo geral) foram testados assumindo que a prevalência da periodontite agressiva é de 1% sob o Equilíbrio de Hardy-Weinberg. Foram coletadas amostras de saliva de 54 das 74 famílias recrutadas, totalizando 371 amostras de saliva para a extração do DNA genômico. 21 polimorfismos de um único nucleotídeo (SNPs) foram selecionados dentro da região proposta e analisados por reação em cadeia da polimerase (PCR). Os genótipos foram obtidos pelo método TaqMan. A análise não paramétrica de ligação familial foi executada com o Programa Merlin. As detecções de transmissão (associação) foram executadas com os programas FBAT e PLINK. O modo de herança mais adequado para cada teste de susceptibilidade dos alelos executado foi o modelo semigeral (p=0,31)...

It has been suggested that the localized aggressive periodontitis phenotype is linked to the region 1q25. The aim of this study was to fine map the chromosome interval suggested as containing a localized aggressive periodontitis locus in clinically well characterized group of families segregating aggressive periodontitis. The hypothesis of this study is that genetic variation located between 1q24.2 to 1q31.3 contributes to the phenotype of aggressive periodontitis. As specific aims, we evaluated the inheritance mode of aggressive periodontitis performing segregation analysis and, we tested the presence of linkage and or association between the target region of chromosome 1 and aggressive periodontitis. Segregation analysis was performed in pedigree data from the first 74 families, comprised of 475 individuals (average of 6.4 individuals per family) with similar geographic origin by the use of the SEGREG program of SAGE v.5.4.2. Mendelian inheritance was assumed to be through an autosomal locus with two alleles A and B, where the A allele was associated with the relevant phenotype. Five inheritance modes (homogeneous no transmission, homogeneous Mendelian transmission, homogeneous general transmission, semi-general transmission, heterogeneous general transmission) were tested assuming the prevalence of aggressive periodontitis as 1% and no deviations from Hardy-Weinberg equilibrium. Saliva samples were collected from 54 families, 371 individuals and DNA was extracted from this biological material. Twenty-one single nucleotide polymorphisms (SNPs) were selected and analyzed by standard polymerase chain reaction. The genotypes were obtained by the TaqMan method. The non-parametric analysis of familial linkage was performed with Merlin software. Analyses of transmission detection (association) were performed by FBAT and PLINK programs. The most parsimonious mode of inheritance in each susceptibility type tested was the semi-general transmission mode (p=0,31)...

A theoretical treatment of interval mapping of a disease gene using transmission disequilibrium tests.

The genetic basis of the transmission disequilibrium test (TDT) for two-marker loci is explored from first principles. In this case, parents doubly heterozygous for a given haplotype at the pair of marker loci that are each in linkage disequilibrium with the disease gene with the further possibility of a second-order linkage disequilibrium are considered. The number of times such parents transmit the given haplotype to their affected offspring is counted and compared with the frequencies of haplotypes that are not transmitted. This is done separately for the coupling and repulsion phases of doubly heterozygous genotypes. Expectations of the counts for each of the sixteen cells possible with four-marker gametic types (transmitted vs not transmitted) are derived. Based on a test of symmetry in a square 4 x 4 contingency table, chi-square tests are proposed for the null hypothesis of no linkage between the markers and the disease gene. The power of the tests is discussed in terms of the corresponding non-centrality parameters for the alternative hypothesis that both the markers are linked with the disease locus. The results indicate that the power increases with the decrease in recombination probability and that it is higher for a lower frequency of the disease gene. Taking a pair of markers in an interval for exploring the linkage with the disease gene seems to be more informative than the single-marker case since the values of the non-centrality parameters tend to be consistently higher than their counterparts in the single-marker case. Limitations of the proposed test are also discussed.

Genuine Bayesian multiallelic significance test for the Hardy-Weinberg equilibrium law

Statistical tests that detect and measure deviation from the Hardy-Weinberg equilibrium (HWE) have been devised but are limited when testing for deviation at multiallelic DNA loci is attempted. Here we present the full Bayesian significance test (FBST) for the HWE. This test depends neither on asymptotic results nor on the number of possible alleles for the particular locus being evaluated. The FBST is based on the computation of an evidence index in favor of the HWE hypothesis. A great deal of forensic inference based on DNA evidence assumes that the HWE is valid for the genetic loci being used. We applied the FBST to genotypes obtained at several multiallelic short tandem repeat loci during routine parentage testing; the locus Penta E exemplifies those clearly in HWE while others such as D10S1214 and D19S253 do not appear to show this.

Heterozygosities of 735 microsatellite markers and background linkage disequilibrium in the Korean population

Suitability of a specific population for linkage disequilibrium mapping studies of complex traits may be assessed by investigating the background linkage disequilibrium (BLD). We are unaware of studies for quantifying the degree of BLD in the Korean population, although the population may be a good candidate for mapping of complex trait genes through whole-genome association studies. It is useful to investigate the properties of genetic isolates in East Asia and to compare them to genetic isolates in Europe. We analyzed the extent of BLD in the Korean population using 735 microsatellite markers and compared the results with the Icelander population, which is one of the European expanded genetic isolates. The Korean population exhibited a level of BLD comparable with the Icelander population. The inference of population structure using the model with admixture showed that each individual has allele copies originating from K populations in equal proportions. Therefore, we believe that factors other than genetic distance, such as recent admixture, have not contributed to the level of BLD. Our results showed that the Korean population, which is an expanded population with no evidence of admixture, has a BLD level comparable with the Icelander population. Therefore, the Korean population can be used for fine mapping of either complex traits or monogenic diseases.

Variación y distribución genética de los SNP's 19, 43 y 63 del gen de susceptibilidad de diabetes tipo 2 Calpaina 10 (Capn10) en la población peruana / Variation and genetic distribution of SNP's 19, 43 y 63 of the susceptibility gene calpain 10 (Capn10) for the type 2 diabetes in the peruvian population

La diabetes tipo 2 es una enfermedad compleja que tiene un componente genético. Calpaina 10 (CAPN10) es un gen de susceptibilidad para este gen y está localizado en 2q37.3. Pacientes de algunas poblaciones de origen amerindio presentan las frecuencias alélicas de los SNP19, 43 y 63 del gen CAPN10, que sugiere una relación causal entre este gen y la biabetes tipo 2. El origen filogenético común, nos permite suponer que CAPN10 también sería un gen de susceptibilidad en la población peruana nativa y mestiza, lo cual nos motivó a investigar esta relación en nuestra población. Se obtuvieron resultados de la frecuencia alélica de los SNP19, 43 y 63 de CAPN10 en 129 controles normales de Lima, la mayoría de origen mestizo. Además de la prueba del equilibrio de Hardy-Weinberg (H-W) para determinar si la población tiene una distribución genéticamente homogénea en dichos marcadores. Se puede concluir que la prueba de H-W sugiere fuertemente que nuestra población control es adecuada para un estudio de asociación y desequilibrio de ligamiento en pruebas caso-control. Esto a su vez es la base para futuros estudios de asociación y desequilibrio de ligamiento, postulando a CAPN10 como gen de susceptibilidad de diabetes tipo 2 en la población peruana.

Type 2 diabetes is a complex genetic disorder, where the gene calpain 10 (CAPN10) located in 2q37.3, plays an important role. Allele frequencies of SNP19, 43 and 63 are present in affected Amerindian populations and might suggest a possible relationship between CAPN10 and type 2 diabetes. The fact that Amerindian populations has a common phyllogenetic origin was our main motivation for studying this possible relation, because it would suggest' that CAPN10 is a susceptibility gene for native and admixed Peruvian populations. Allelic frequencies of SNP19, 43 and 63 of calpain 10 was obtained of 129 normal controls from Lima, most of them admixed population. Hardy-Weinberg test (H-W) was used in order to determine if the population had a genetically homogenous distribution for the employed molecular markers. It can be concluded that the H-W test strongly suggests that the control population is adequate for an association and linkage disequilibrium in case-control studies. Furthermore, this would mean be thstart of future association and linkage disequilibrium studies where CAPN10 would be considered as a susceptibility gene for type 2 diabetes in Peruvian population.

Estudio de asociación por desequilibrio de ligamiento entre los genes TGFA, RARA, y BCL3 y fisura labiopalatina no sindrómica (FLPNS) en la población chilena / Possible association due to linkage disequilibrium of TGFA, RARA and BCL3 with nonsyndromic cleft lip with or without cleft palate in the Chilean population

Background: Nonsyndromic cleft lip/palate (NSCLP) is a congenital malformation with the characteristics of a complex genetic trait. Based on experimental evidences as well as on association and linkage studies candidate genes TGFA, RARA and BCL3 have been postulated as being involved in the genetic etiology of this pathology. Aim: To test the possible association due to linkage disequilibrium between microsatellite markers located at less than 1cM from the three candidate genes and nonsyndromic cleft lip/palate using the case-parents trio design. Patients and Methods: The sample consisted of 58 case-parents trios. Two microsatellite markers, flanking each one of the candidate genes were analyzed by means of the polymerase chain reaction (PCR) with fluorescent labeled microsatellite markers. Electrophoresis of the PCR products was performed on a laser-fluorescent automatic DNA sequencer. Nonparametric ETDT was used to analyze the genotype data. Results: Significant linkage disequilibrium was detected between D2S443 (TGFA) and NSCLP. Significance was almost reached between D17S800 (RARA) and NSCLP. Alleles 239bp (D2S443) and 172bp (D17S800) showed significant preferential transmission from heterozygous parents to affected offspring. In the case of BCL3 both markers showed no significant results. Conclusions: The results of the present study do not show clear evidence that TGFA or RARA could be involved in the genetic etiology of NSCLP. Even though the importance of retinoic acid in the development of the embryo is well documented the results obtained for RARA are difficult to analyze. In relation to the possible role of BCL3 in NSCLP, recent information postulates that other genes located in the same chromosome region could be involved in NSCLP.

A priori choice of hybrid parents in plants

Plant breeding deals with high-yielding genotypes. However, how best to choose parents of these genotypes remains an unsolved question. Here, we focus on a priori choice based on parental distances by means of agronomic and molecular data. Despite numerous theoretical and empirical studies, a priori choice continues to be a controversial procedure. Both success and failure are commonly reported. We looked at these ambiguous results in order to investigate their possible causes. A total of 139 articles on genetic divergence were sampled to examine aspects such as type and number of markers utilized. We suggest that the mean number of 160, 281 and 25 for RAPD and RFLP markers, and SSR loci, respectively, which we found in these papers, should be increased for accurate analysis. A second sample composed of 54 articles was used to evaluate the divergence-heterosis association. Most of them (28) detected positive divergence-heterosis association, whereas 26 revealed negative or inconclusive results. We examined several causes that influence a priori choice positively and negatively.