Ethnic variation in the most common shade of anterior teeth among malaysian students: a cross-sectional study / Variación del tono más común de los dientes anteriores entre estudiantes malasios de diferentes etnias: un estudio transversal

Aim: Determination of the most common shade of anterior teeth in Malaysian students of different ethnicities. Materials and Methods: A total of 120 subjects, 40 each from different ethnicities (Malay, Chinese, and Indian) aged 18-22 years were evaluated for tooth shade using the VITA Classical shade guide. The subject was asked to sit in an up-right position with teeth at the clinician's eye level and the subject was instructed to remove makeup or tinted eyewear which may affect the result. The procedure was done in natural daylight. The shade tabs were positioned adjacent to the maxillary central incisor and the middle 1/3rd of the facial surface was assessed by experts to determine the correct tooth shade. The data was statistically analysed. Results: The differences in tooth shade were seen among the subjects of different ethnicities. The Malay ethnicity has B1 (37%) as the most common tooth shade whereas Chinese has C1 (27%) and Indian C1 (40%). Conclusions: Under the limitation of the study, it was found that there is a relationship between tooth color and ethnic background. Malay students tend to have brighter teeth as compared to Chinese and Indian students.

Objetivo: Determinar el tono más común de los dientes anteriores en estudiantes malasios de diferentes etnias. Materiales y Métodos: Se evaluó el color de los dientes de un total de 120 sujetos, 40 de diferentes etnias (malayos, chinos e indios) de edades comprendidas entre 18 y 22 años, utilizando la guía de colores VITA Classical. Se pidió al sujeto que se sentara en posición vertical con los dientes al nivel de los ojos del médico y se le indicó que se quitara el maquillaje o las gafas teñidas, lo que podría afectar el resultado. El procedimiento se realizó con luz natural. Las pestañas de color se colocaron adyacentes al incisivo central superior y expertos evaluaron el tercio medio de la superficie facial para determinar el tono correcto del diente. Los datos fueron analizados estadísticamente. Resultados: Se observaron diferencias en el color de los dientes entre los sujetos de diferentes etnias. La etnia malaya tiene el B1 (37%) como el color de dientes más común, mientras que los chinos tienen el C1 (27%) y los indios C1 (40%). Conclusión: Bajo las limitaciones del estudio, se encontró que existe una relación entre el color de los dientes y el origen étnico. Los estudiantes malayos tienden a tener dientes más brillantes en comparación con los estudiantes chinos e indios.

The groove configuration of mandibular molars of malaysians of mongoloid ancestry / Configuración del surco de los molares mandibulares de los malayos de ascendencia mongoloide

Aim: Variation in dental structures is widely accepted as a combination of multiple factors such as gender, environmental effects and genetics. However, the characterization of similarities and differences in dental morphology has been lacking in relation to the factors mentioned. This study aims to assess and compare the variations in traits in mandibular molars and the influence of gender and ethnicity in affecting these traits amongst the Malaysian population of Mongoloid ancestry. Materials and Methods: Our study population was 180 dental casts of patients, from 15 to 40 years old, comprising 56 Malays and 124 Chinese; 60 were males and 120 were females. Traits like groove pattern, number of cusps, protostylids and deflecting wrinkles were observed, scored, and recorded. Results: This study revealed that the most common mandibular first molar (M1) was characterized by 5 cusps and displayed 'Y' groove pattern, while the most common mandibular second molar (M2) had 4 cusps and exhibited a groove pattern that resembled a '+'. Notably, all the traits studied were bilaterally symmetrical, except for the groove pattern of M1, while sexual dimorphism was observed in groove patterns of M2. Conclusions: This study found that M1 had a preponderance of 5 cusps with 'Y' groove pattern, while M2 were typically 4-cusped with '+' groove pattern.

Objetivo: La variación en las estructuras dentales es ampliamente aceptada como el resultado de una combinación de múltiples factores como el género, los efectos ambientales y la genética. Sin embargo, ha faltado la caracterización de similitudes y diferencias en la morfología dental en relación a los factores mencionados. Este estudio tiene como objetivo evaluar y comparar las variaciones en los rasgos de los molares mandibulares y la influencia del género y la etnia al afectar estos rasgos entre la población malaya de ascendencia mongoloide. Materiales y Métodos: Nuestra población de estudio fue de 180 modelos dentales de pacientes, de 15 a 40 años,conformados por 56 malayos y 124 chinos; 60 eran hombres y 120 eran mujeres. Se observaron, puntuaron y registraron rasgos como el patrón de surcos, el número de cúspides, los protostílidos y las arrugas desviadas. Resultados: Este estudio reveló que el primer molar mandibular más común (M1) se caracterizaba por 5 cúspides y mostraba un patrón de ranura en 'Y', mientras que el segundo molar mandibular más común (M2) tenía 4 cúspides y exhibía un patrón de ranura que se parecía a un ' +'. En particular, todos los rasgos estudiados eran bilateralmente simétricos, excepto el patrón de surco de M1, mientras que se observó dimorfismo sexual en los patrones de surco de M2. Conclusión: Este estudio encontró que M1 tenía una preponderancia de 5 cúspides con un patrón de ranura en 'Y', mientras que M2 tenía típicamente 4 cúspides con un patrón de ranura '+'.

Neutrophil-lymphocyte ratios in the prognostication of primary non-metastatic nasopharyngeal carcinoma / Neutrophil-lymphocyte ratios in the prognostication of primary non-metastatic nasopharyngeal carcinoma

Abstract Introduction: Nasopharyngeal carcinoma is a geographically and racially variable disease which has a high incidence in Malaysia. Based on current concepts in tumour related inflammation the inflammatory marker, neutrophil-lymphocyte ratio was tested to find its relationship with prognosis in nasopharyngeal carcinoma. Objective: To investigate the effect of the neutrophil-lymphocyte ratio on prognosis in non-metastatic primary nasopharyngeal carcinoma patients and to further refine the cut off between high and low neutrophil-lymphocyte ratio values. Methods: The medical charts of patients with histologically confirmed nasopharyngeal carcinoma from 1st January 2005 until 31st December 2009 were reviewed retrospectively and theneutrophil-lymphocyte ratio was calculated to see if there was any association between their higher values with higher failure rates. Results: Records of 98 patients (n = 98) were retrieved and reviewed. Only neutrophil-lymphocyte ratio (p = 0.004) and tumor node metastasis staging (p = 0.002) were significantly different between recurrent and non-recurrent groups, with the neutrophil-lymphocyte ratio being independent of tumor node metastasis staging (p = 0.007). Treatment failure was significantly higher in the high neutrophil-lymphocyte ratio group (p = 0.001). Disease free survival was also significantly higher in this group (p = 0.000077). Conclusion: High neutrophil-lymphocyte ratio values are associated with higher rates of recurrence and worse disease free survival in non-metastatic nasopharyngeal carcinoma patients undergoing primary curative treatment.

Resumo: Introdução: O carcinoma de nasofaringe é uma doença variável geográfica e etnicamente, com alta incidência na Malásia. Baseado em conceitos atuais sobre inflamação relacionada a tumores, o marcador inflamatório relação neutrófilos/linfócitos foi testado para verificar sua relação com o prognóstico dessa condição clínica. Objetivo: Investigar o efeito do marcador neutrófilos/linfócitos no prognóstico de pacientes com primários não metastáticos de nasofaringe e refinar o ponto de corte entre valores altos e baixos da relação neutrófilos/linfócitos. Método: Os prontuários médicos dos pacientes com carcinoma de nasofaringe confirmado histologicamente de 1º de janeiro de 2005 até 31 de dezembro de 2009 foram revisados retrospectivamente e a relação neutrófilos/linfócitos foi calculada para verificar se havia alguma associação entre valores maiores e aumento na taxa de falha de tratamento. Resultados: Os dados de 98 pacientes (n = 98) foram revisados. Apenas a relação neutrófilos/linfócitos (p = 0,004) e o estadiamento TNM (p = 0,002) foram significantemente diferentes entre os grupos recorrentes e os não recorrentes, a relação neutrófilos/linfócitos foi independente do estadiamento TNM (p = 0,007). A falha de tratamento foi significantemente maior no grupo com relação neutrófilos/linfócitos alta (p = 0,001). A sobrevida livre de doença também foi significantemente maior nesse grupo (p = 0,000077). Conclusão: Os altos valores da relação neutrófilos/linfócitos estão associados a maiores taxas de recorrência e menor tempo de sobrevida livre de doença em pacientes com carcinomas não metastáticos de nasofaringe submetidos a tratamento curativo primário.

Neutrophil-lymphocyte ratios in the prognostication of primary non-metastatic nasopharyngeal carcinoma.

INTRODUCTION: Nasopharyngeal carcinoma is a geographically and racially variable disease which has a high incidence in Malaysia. Based on current concepts in tumour related inflammation the inflammatory marker, neutrophil-lymphocyte ratio was tested to find its relationship with prognosis in nasopharyngeal carcinoma. OBJECTIVE: To investigate the effect of the neutrophil-lymphocyte ratio on prognosis in non-metastatic primary nasopharyngeal carcinoma patients and to further refine the cut off between high and low neutrophil-lymphocyte ratio values. METHODS: The medical charts of patients with histologically confirmed nasopharyngeal carcinoma from 1st January 2005 until 31st December 2009 were reviewed retrospectively and theneutrophil-lymphocyte ratio was calculated to see if there was any association between their higher values with higher failure rates. RESULTS: Records of 98 patients (n=98) were retrieved and reviewed. Only neutrophil-lymphocyte ratio (p=0.004) and tumor node metastasis staging (p=0.002) were significantly different between recurrent and non-recurrent groups, with the neutrophil-lymphocyte ratio being independent of tumor node metastasis staging (p=0.007). Treatment failure was significantly higher in the high neutrophil-lymphocyte ratio group (p=0.001). Disease free survival was also significantly higher in this group (p=0.000077). CONCLUSION: High neutrophil-lymphocyte ratio values are associated with higher rates of recurrence and worse disease free survival in non-metastatic nasopharyngeal carcinoma patients undergoing primary curative treatment.

Association of glycemic control with progression of diabetic retinopathy in type 2 diabetes mellitus patients in Malaysia

Abstract The risk of having microvascular complication is high among Type 2 Diabetes Mellitus (T2DM) patients. However, factors associated with the glycemic control and progression of diabetic retinopathy (DR) in T2DM patients is limited. This study aims to determine association between anti-diabetic agents, glycemic control and progression of diabetic retinopathy in a Malaysian population. A retrospective study conducted in a tertiary teaching hospital in Malaysia, from January 2009 until March 2014. This study enrolled 104 patients aged 40-84 years, with a mean age 63.12 ± 9.18 years. patients had non-proliferative diabetic retinopathy (NPDR, 77%) and 35% had proliferative diabetic retinopathy (PDR). Diabetic macula edema (DME) was present in 20% of NPDR patients, compared with 7% in PDR. Alpha-glucosidase inhibitor (p=0.012), age (p=0.014) and number of antidiabetic agents used (p=0.015) were significantly associated with stages of diabetic retinopathy. Family history of T2DM (p=0.039) was associated with DME. Identifying factors influencing the progression of diabetic retinopathy may aid in optimizing the therapeutic effects of anti-diabetic agents in T2DM patients.

Demographic, clinical and lifestyle predictors for severity of erectile dysfunction and biomarkers level in Malaysian patients

The incidence of erectile dysfunction (ED) is rising worldwide and its prevalence is one of the main health concerns that affect overall men well-being in Malaysia. The cluster of demographic, clinical and lifestyle factors may have contributed to the severity of ED and changes in biomarkers level; nevertheless these have not been studied extensively. This cross sectional study involved a total of 276 patients with 138 was diagnosed with ED. The demographic, clinical, lifestyle factors and severity of ED were assessed using a set of questionnaire and the International Index of Erectile Function (IIEF-5). Meanwhile, Total Testosterone (TT) and Asymmetric dimethylarginine (ADMA) levels were determined using the enzyme-linked immunosorbant assay (ELISA). Binary logistic regression test was used to demonstrate the predictors of severity of ED, TT and ADMA levels. Significant predictors for worsening of severity of ED are self-employed [10.55 (0.43 - 257.06), p=0.004], pensioner [8.07 (0.19 - 352.45), p=0.026], non-government employee [1.16 (0.05 - 26.26), p=0.04] and TT [0.41 (0.25 - 0.69), p=0.001]. Nevertheless, pensioner [0.08 (0.01 - 0.87), p=0.038] and unemployed [0.04 (0.01 - 0.42), p=0.007], were the predictors that may influence the changes of TT levels. On the other hand, academic qualification (secondary) [4.51 (0.48 - 42.83), p=0.014] and intensity of physical activities (< 1 hour/day) [2.61 (0.65 - 10.48), p=0.008] were the predictors which were more likely to influence the changes of ADMA levels in ED patients. TT and ADMA levels were influenced by demographic and lifestyle factors whilst severity of ED was predicted by demographic and clinical factors in Malaysian ED population. These predictors may provide new knowledge on risk factors of severity of ED and help in management of ED. Thus, the predictive models could serve as a primary guidance to physicians to ensure ED being managed and treated more effectively.

Barriers to the provision of asthma services and perceived practice towards asthma management among urban community pharmacists in Selangor, Malaysia

This study aims to assess the perceived practice and barriers towards the provision of asthma management services among urban community pharmacists in Selangor, Malaysia. The study also highlights both pharmacist and patient-related barriers in asthma counseling. One hundred fifty urban community pharmacists in Selangor, Malaysia, were randomly selected and recruited for the present cross sectional baseline study. Previous studies have explored pharmacists' perception on their roles in asthma management in different parts of the world. The data was collected through self-explanatory questionnaires (containing 47 items). The extracted data from the completed questionnaires were analyzed descriptively and inferentially using Statistical Package for Social Science (SPSS) version 19. Results showed that pharmacists perceived their roles in asthma management along three major dimensions: 'patient self-management', 'medication use' and 'asthma control', mean (±SD) score of the perception towards asthma management was 99.29 ± 4.58 over a maximum possible score of 110 with 90.26%. There were significant differences between the pharmacy education level and perceived practice of asthma management while there were insignificant differences between age, gender, ethnicity, number of practicing year and perceived practice of asthma management among respondents. Most common barriers towards asthma counselling including lack of time, lack of asthma knowledge, lack of counselling space and cost of asthma drugs. Conclusively, urban community pharmacists in Selangor, Malaysia, demonstrate good perceived practice of better management of asthma with multidimensional dimensional role against in disease care.

Familiarity with Own Population's Appearance Influences Facial Preferences.

Previous studies have found that individuals from rural areas in Malaysia and in El Salvador prefer heavier women than individuals from urban areas. Several explanations have been proposed to explain these differences in weight preferences but no study has explored familiarity as a possible explanation. We therefore sought to investigate participants' face preferences while also examining the facial characteristics of the actual participants. Our results showed that participants from rural areas preferred heavier-looking female faces than participants from urban areas. We also found that the female faces from the rural areas were rated as looking heavier than the female faces from the urban areas. Our findings are consistent with the hypothesis that familiarity may be contributing to the differences found in face preferences between rural and urban areas given that people from rural and urban areas are exposed to different faces.

Experience of menopause in aboriginal women: a systematic review.

Every woman experiences the menopause transition period in a very individual way. Menopause symptoms and management are greatly influenced by socioeconomic status in addition to genetic background and medical history. Because of their very unique cultural heritage and often holistic view of health and well-being, menopause symptoms and management might differ greatly in aboriginals compared to non-aboriginals. Our aim was to investigate the extent and scope of the current literature in describing the menopause experience of aboriginal women. Our systematic literature review included nine health-related databases using the keywords 'menopause' and 'climacteric symptoms' in combination with various keywords describing aboriginal populations. Data were collected from selected articles and descriptive analysis was applied. Twenty-eight relevant articles were included in our analysis. These articles represent data from 12 countries and aboriginal groups from at least eight distinctive geographical regions. Knowledge of menopause and symptom experience vary greatly among study groups. The average age of menopause onset appears earlier in most aboriginal groups, often attributed to malnutrition and a harsher lifestyle. This literature review highlights a need for further research of the menopause transition period among aboriginal women to fully explore understanding and treatment of menopause symptoms and ultimately advance an important dialogue about women's health care.

Sex hormones in Malay and Chinese men in Malaysia: are there age and race differences?

OBJECTIVES: Variations in the prevalence of sex-hormone-related diseases have been observed between Asian ethnic groups living in the same country; however, available data concerning their sex hormone levels are limited. The present study aimed to determine the influence of ethnicity and age on the sex hormone levels of Malay and Chinese men in Malaysia. METHODS: A total of 547 males of Malay and Chinese ethnicity residing in the Klang Valley Malaysia underwent a detailed screening, and their blood was collected for sex hormones analyses. RESULTS: Testosterone levels were normally distributed in the men (total, free and non-sex hormone-binding globulin (SHBG) bound fractions), and significant ethnic differences were observed (p<0.05); however, the effect size was small. In general, testosterone levels in males began to decline significantly after age 50. Significant ethnic differences in total, free and non-SHBG bound fraction estradiol levels were observed in the 20-29 and 50-59 age groups (p<0.05). The estradiol levels of Malay men decreased as they aged, but they increased for Chinese men starting at age 40. CONCLUSIONS: Small but significant differences in testosterone levels existed between Malay and Chinese males. Significant age and race differences existed in estradiol levels. These differences might contribute to the ethnic group differences in diseases related to sex hormones, which other studies have found in Malaysia.

Sex hormones in Malay and Chinese men in Malaysia: are there age and race differences?

OBJECTIVES: Variations in the prevalence of sex-hormone-related diseases have been observed between Asian ethnic groups living in the same country; however, available data concerning their sex hormone levels are limited. The present study aimed to determine the influence of ethnicity and age on the sex hormone levels of Malay and Chinese men in Malaysia. METHODS: A total of 547 males of Malay and Chinese ethnicity residing in the Klang Valley Malaysia underwent a detailed screening, and their blood was collected for sex hormones analyses. RESULTS: Testosterone levels were normally distributed in the men (total, free and non-sex hormone-binding globulin (SHBG) bound fractions), and significant ethnic differences were observed (p<0.05); however, the effect size was small. In general, testosterone levels in males began to decline significantly after age 50. Significant ethnic differences in total, free and non-SHBG bound fraction estradiol levels were observed in the 20-29 and 50-59 age groups (p<0.05). The estradiol levels of Malay men decreased as they aged, but they increased for Chinese men starting at age 40. CONCLUSIONS: Small but significant differences in testosterone levels existed between Malay and Chinese males. Significant age and race differences existed in estradiol levels. These differences might contribute to the ethnic group differences in diseases related to sex hormones, which other studies have found in Malaysia.

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 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.

Lack of association between RANTES-28, SDF-1 gene polymorphisms and systemic lupus erythematosus in the Malaysian population.

Regulated on activation, normal T-cell expressed and secreted (RANTES) and stromal cell-derived factor 1 (SDF-1) are members of the CC- and CXC-chemokine families, respectively. Both genes have been postulated to be involved in the pathogenesis of systemic lupus erythematosus (SLE). We analyzed position 28 of the RANTES gene promoter region, as well as the SNP observed in the 3' UTR of the SDF-1 gene at position 801, in 130 patients presenting SLE at the Malaya University Medical Centre. Screening of 130 healthy volunteer controls using RFLP was also performed. RANTES-28 polymorphism analysis showed no significant (P = 0.3520) relationship, even though homozygous C/C was more frequent in SLE patients (OR = 1.4183) and heterozygous C/G was more frequent in healthy controls (OR = 0.7051). There were no significant (P = 0.2650) associations between A/A (OR = 0.783), G/G (OR = 1.5914) and G/A (OR = 0.8289) genotypes in the SDF-1 gene polymorphism with SLE. We conclude that there is no significant association of RANTES-28 and SDF-1 gene polymorphisms and occurrence of SLE in Malaysia.

Study of prosopic (Facial) index of Indian and Malaysian students / Estudio del índice prosopo (Facial) de estudiantes de la India y Malasia

For several generations physical anthropologists measured skulls in the belief that thereby they were likely to obtain results, this would enable them to trace the relationships between the races of mankind. It was believed that the form of the skull in particular remained constant in each race, and that different races typically showed different facial indices. Form of the head and face is now known to be subject to change through environmental influences. Measurement is necessary in order to obtain this kind of knowledge, and in order to be able to give as accurate a description of an individual or group of individuals as possible. The present study aimed at measuring facial index of both sex in Malaysian and Indian students. 300 students of both nations were measured for face length and face width and facial index was calculated. Malaysian males had a mean facial index of 85.72 and females had marginally higher value 87.71. Both belonged to Mesoprosopic face type and were statistically significant. Indian males had a mean facial index of 87.19 where as 86.75 in females. Both belonged to Mesoprosopic face type, and comparison of facial index was statistically not significant. Comparison between Indian and Malaysian subjects indicates that Indians (both sexes together) had a higher (87.04) mean facial index than Malaysians (86.76). However, this difference was statistically not significant.

Por muchas generaciones los antropólogos físicos han medido cráneos con la finalidad de obtener resultados permitiéndoles trazar relaciones entre diferentes razas de la humanidad. Se creía que la forma del cráneo se mantenía constante en cada raza, y que las diferentes razas mostraban diferentes índices faciales. En la actualidad se sabe que la forma de la cabeza y la cara están sujetas a cambios debido a las influencias ambientales. Las mediciones son necesarias para obtener este tipo de conocimiento, con el fin de poder dar la descripción más exacta de un individuo o grupo de personas. El presente estudio tuvo como objetivo medir el índice facial en estudiantes de ambos sexos de Malasia e India. 300 estudiantes de ambas naciones fueron medidos para determinar la longitud de la cara, el ancho de la cara y determinar el índice facial. Los hombres de Malasia tuvieron un promedio de índice facial de 85,72 y las mujeres tuvieron un valor ligeramente superior (87,71). Ambos pertenecieron al tipo de cara mesoprosópicas y las diferencias fueron estadísticamente significativas. Los hombres indios tuvieron un índice facial medio de 87,19, y las mujeres 86,75. Ambos pertenecieron al tipo de cara mesoprosópicas y la comparación del índice de la cara no fue estadísticamente significativa. La comparación entre sujetos de la India y Malasia indicó que los indios (de ambos sexos en conjunto) tuvieron mayor índice facial (87,04) que los malasios (86,76). Sin embargo, esta diferencia no fue estadísticamente significativa.

Genetic data for 15 STR loci in a Kadazan-Dusun population from East Malaysia.

Allele frequencies of 15 short tandem repeat (STR) loci, namely D5S818, D7S820, D13S317, D16S539, TH01, TPOX, Penta D, Penta E, D3S1358, D8S1179, D18S51, D21S11, CSF1PO, vWA, and FGA, were determined for 154 individuals from the Kadazan-Dusun tribe, an indigenous population of East Malaysia. All loci were amplified by polymerase chain reaction, using the Powerplex 16 system. Alleles were typed using a gene analyzer and the Genemapper ID software. Various statistical parameters were calculated and the combined power of discrimination for the 15 loci in the population was calculated as 0.999999999999999. These loci are thus, informative and can be used effectively in forensic and genetic studies of this indigenous population.

Phylogenetic relationships of the Orang Asli and Iban of Malaysia based on maternal markers.

Malaysia remains as a crossroad of different cultures and peoples, and it has long been recognized that studying its population history can provide crucial insight into the prehistory of Southeast Asia as a whole. The earliest inhabitants were the Orang Asli in Peninsular Malaysia and the indigenous groups in Sabah and Sarawak. Although they were the earliest migrants in this region, these tribes are divided geographically by the South China Sea. We analyzed DNA sequences of 18 Orang Asli using mitochondrial DNA extracted from blood samples, each representing one sub-tribe, and from five Sarawakian Iban. Mitochondrial DNA was extracted from hair samples in order to examine relationships with the main ethnic groups in Malaysia. The D-loop region and cytochrome b genes were used as the candidate loci. Phylogenetic relationships were investigated using maximum parsimony and neighbor joining algorithms, and each tree was subjected to bootstrap analysis with 1000 replicates. Analyses of the HVS I region showed that the Iban are not a distinct group from the Orang Asli; they form a sub-clade within the Orang Asli. Based on the cytochrome b gene, the Iban clustered with the Orang Asli in the same clade. We found evidence for considerable gene flow between Orang Asli and Iban. We concluded that the Orang Asli, Iban and the main ethnic groups of Malaysia are probably derived from a common ancestor. This is in agreement with a single-route migration theory, but it does not dismiss a two-route migration theory.

Linkage of schizophrenia with TPH2 and 5-HTR2A gene polymorphisms in the Malay population.

The serotoninergic system has been implicated in the etiology of schizophrenia and other behavioral disorders. Association studies have focused on the tryptophan hydroxylase 2 gene (TPH2) and the 5-hydroxytryptamine receptor 2A gene (5-HTR2A). We genotyped two single-nucleotide polymorphisms, A1438G of 5-HTR2A and intronic rs1386494 of TPH2 in the Malay population, using a sample size of 289 schizophrenic patients and 130 healthy controls. We found a significant association of A1438G of 5-HTR2A with schizophrenia in Malays. On the other hand, TPH2 polymorphism was not associated with schizophrenia. This is the first genetic association study concerning schizophrenia in the Malay population.