Observation and analysis of STR loci mutation among 1 786 cases of paternity test in Guangxi area / 重庆医学

Objective To observe and analyze the mutation characteristics of 17 STR loci among the paternity test cases in Guangxi area .Methods Among 1 786 cases of non—exclusion parentage ,1 430 cases were parental triplet and 356 cases were uniparental diad ,1 001 persons were Han people ,2 102 persons were Zhuang people and 113 persons were other ethnic group in the parents .The genome DNA was extracted by Chelex-100 method .17 short tandem repeat (STR) loci were detected by Power Plex ? 18D System Kit .The paternity testing containing mutant STR loci were screened out from 1786 cases .The locus-specific ,specificity of paternal and maternal ,and allele-specific mutation rates were observed and analyzed ,respectively .The characteristics of the muta-tions were studied .Results In total ,75 mutations events were observed at 16 of the 17 loci .Among them ,73 (97 .34% ) times were one step mutation ,onece(1 .33% ) was two—step mutation ,and once(1 .33% ) was three—step mutation ,no mutation was found at the TPOX locus .The mutation rates ranged 0 .031 1% —0 .404 2% ,and the mean mutation rate was 0 .145 8% .The proportion of the paternal mutations and the maternal mutations was 5 .4:1 .0 ,the difference had statistical significance(P0 .05) .Conclusion STR loci mutation is common phenomenon in paternity test .The data of STR loci mutations should be constantly accumulated for selecting the genetic characteristics in line with the Guangxi population and the genetic markers of STR loci with high identification ability to ensure ac-curate and reliable identification results .

Genotipificación de Mycobacterium leprae colombiano para la determinación de patrones de transmisión de la enfermedad / Genotyping colombian Mycobacterium leprae for determining disease transmission patterns

Objetivo Evaluar la variabilidad de VNTR (variable-number tandem repeat) de Mycobacterium leprae de pacientes colombianos con y sin tratamiento previo para identificar posibles fuentes de infección y entender los patrones de transmisión de la enfermedad. Metodología Estudio transversal descriptivo, en donde mediante un muestreo electivo a conveniencia se tomaron 161 biopsias de pacientes multibacilares de lepra, que habían sido solicitadas para diagnóstico y seguimiento de la enfermedad, de las cuales se realizó extracción de ADN de M. leprae y usando la técnica de PCR para VNTRs de M. leprae estandarizada, se establecieron los genotipos y los diferentes clusters mediante el agrupamiento apareado UPGMA. Resultados En las 161 muestras totales se hallaron 22 genotipos VNTRs diferentes, de las cuales 100 muestras (62,1 por ciento) pertenecían al genotipo único VNTRU, y de los genotipos restantes, los mayoritarios, es decir los que dieron lugar a formación de grupos o clusters fueron VNTR17 (5,6 por ciento), VNTR20 (4,3 por ciento), VNTR18 (4,3 por ciento), VNTR14 (4,3 por ciento) y VNTR13 (3,7 por ciento). Conclusión En este estudio se evidencia por análisis de agrupamiento que se pueden detectar clones con diferente grado de virulencia/agresividad, lo cual implica la necesidad de incrementar varias de las actividades del programa de control que darán como resultado la verdadera disminución de la transmisión del microorganismo.

Objective Assessing VNTR (variable-number tandem repeat) variability of Mycobacterium leprae from Colombian patients with and without prior treatment to identify potential sources of infection and to understand the patterns of disease transmission. Methodology This was a descriptive cross-sectional study where a convenience sample of biopsies was taken from 161 multibacillary leprosy patients; diagnosis and monitoring of the disease had been requested for these patients. DNA was extracted from M. leprae and standardised using the PCR technique for M. leprae VNTR, ge­notypes were established and different clusters grouped by unweighted pair group method with arithmetic mean (UPGMA). Results 22 different VNTR genotypes were found from 161 samples, of which 100 samples (62.1 percent) had a single u-VNTR genotype and the remaining genotypes were VNTR 17 (5.6 percent), VNTR 20 (4.3 percent), VNTR 18 (4.3 percent), VNTR 14 (4.3 percent) and VNTR 13 (3.7 percent), namely those forming groups or clusters. Conclusion This study showed that clones can be detected with varying degrees of virulence / aggressiveness by cluster analysis, implying the need for more monitoring programme activities which will result in a real decline in microorganism transmission.