Skin Pigmentation Differences between Mongolian, Korean, and Uzbekistan Ancient Human DNA Samples

Background. This study reports the use of real-time PCR to identify the SNP rs1545397 in the intron region on the OCA2 gene from ancient and degraded DNA isolated from ancient human bones from Mongolia, Korea, and Uzbekistan. This SNP is a marker for skin pigmentation. LightCycler-based probes (HybProbes) were designed. A LightCycler (version 2.0) system was used for the real-time PCR. Results. The results of the real-time PCRs of three different genotypes of SNP rs1545397 were compared with those of the direct sequencing. Melting curve analysis was used for genotype determination. Three genotypes were distinguished: the homozygous T (T/T) SNP type formed a distinct melting peak at 53.3±0.14°C, the homozygous A (A/A) SNP type formed a distinct melting peak at 57.8±0.12°C, and the heterozygous A/T SNP type formed two distinct melting peaks at 53.3±0.17°C and 57.8±0.15°C. Mongolian aDNA samples tested in this study carried all three types of the SNP (A/T, A/A, and T/T) with no distinctly predominant type observed. In contrast, Korean aDNA samples carried the Asian genotype (T/T), while the Uzbekistan aDNA samples carried the European genotype (A/A) more often than the Asian genotype (T/T). Conclusions. Human Mongolian aDNA samples had A/T, A/A, and T/T SNP rs1545397 with no distinct predominant genotype. When combined with the archeological and aDNA studies of other coupling morphologies with aDNA, our results infer that Mongolia’s prehistoric population had considerable heterogeneity of skin color and morphological traits and that in the Neolithic period, a Eurasian or mixed population inhabited the western part of Mongolia.

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SIMPLIFYING CELIAC DISEASE PREDISPOSING HLA-DQ ALLELES DETERMINATION BY THE REAL TIME PCR METHOD

Arquivos de Gastroenterologia ◽

10.1590/s0004-28032015000200013 ◽

2015 ◽

Vol 52 (2) ◽

pp. 143-146 ◽

Cited By ~ 6

Author(s):

Nicole SELLESKI ◽

Lucas Malta ALMEIDA ◽

Fernanda Coutinho de ALMEIDA ◽

Lenora GANDOLFI ◽

Riccardo PRATESI ◽

...

Keyword(s):

Celiac Disease ◽

Real Time ◽

Internal Control ◽

Real Time Pcr ◽

Melting Curve ◽

Melting Curve Analysis ◽

Specific Primers ◽

The Real ◽

Hla Dq ◽

Pcr Method

Background Celiac disease is an autoimmune enteropathy triggered by the ingestion of gluten in genetically susceptible individuals. Genetic susceptibility is associated with two sets of alleles, DQA1*05 - DQB1*02 and DQA1*03 - DQB1*03:02, which code for class II MHC DQ2 and DQ8 molecules, respectively. Approximately 90%-95% of celiac patients are HLA-DQ2 positive, and half of the remaining patients are HLA-DQ8 positive. In fact, during a celiac disease diagnostic workup, the absence of these specific DQA and DQB alleles has a near perfect negative predictive value. Objective Improve the detection of celiac disease predisposing alleles by combining the simplicity and sensitivity of real-time PCR (qPCR) and melting curve analysis with the specificity of sequence-specific primers (SSP). Methods Amplifications of sequence-specific primers for DQA1*05 (DQ2), DQB1*02 (DQ2), and DQA1*03 (DQ8) were performed by the real time PCR method to determine the presence of each allele in independent reactions. Primers for Human Growth Hormone were used as an internal control. A parallel PCR-SSP protocol was used as a reference method to validate our results. Results Both techniques yielded equal results. From a total of 329 samples the presence of HLA predisposing alleles was determined in 187 (56.8%). One hundred fourteen samples (61%) were positive for a single allele, 68 (36.3%) for two alleles, and only 5 (2.7%) for three alleles. Conclusion Results obtained by qPCR technique were highly reliable with no discordant results when compared with those obtained using PCR-SSP.

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