Portable plastic syringe as a self-actuated pump for long-distance uniform delivery of liquid inside a microchannel and its application for flow-through polymerase chain reaction on chip

A strategy for realizing self-actuated pumping with uniform flow rate over a long distance is introduced using hands-on operation of disposable syringe, and was applied for on-chip flow-through PCR inside a serpentine PMMA microchannel.

Development of a passive micromixer based on repeated fluid twisting and flattening, and its application to DNA purification

We have developed a three-dimensional passive micromixer based on new mixing principles, fluid twisting and flattening. This micromixer is constructed by repeating two microchannel segments, a "main channel" and a "flattened channel", which are very different in size and are arranged perpendicularly. At the intersection of these segments the fluid inside the micromixer is twisted and then, in the flattened channel, the diffusion length is greatly reduced, achieving high mixing efficiency. Several types of micromixer were fabricated and the effect of microchannel geometry on mixing performance was evaluated. We also integrated this micromixer with a miniaturized DNA purification device, in which the concentration of the buffer solution could be rapidly changed, to perform DNA purification based on solid-phase extraction.

On the genetic uniqueness of the Ami aborigines of Formosa

In the attempt to reconstruct the prehistory of Pacific and Indian Ocean populations, Taiwan's aborigines appear to be of particular interest. Linguistic and archeological evidence indicates that the dispersal of Austronesian speakers throughout the islands of Oceania and Southeast Asia may have originated from Taiwan about 5,000 years ago. The Ami are Taiwan's largest aboriginal group. Here, we report on six polymorphic point mutation loci in Ami individuals and compare allelic frequencies to worldwide populations. In order to examine the genetic characteristics and relationships of the Ami aborigines, we used the allelic frequency data to generate expected heterozygosities, power of discrimination values, maximum likelihood phylogenetic trees, principal component maps, and centroid gene flow plots. These analyses argue for the genetic isolation and uniqueness of the Ami people. Data supportive of limited gene flow and/or small population size, as well as genetic similarities to Native Americans, were observed.

Distribution of the HLA-DQA1 and polymarker alleles in the Basque population of Spain

HLA-DQA1 and polymarker (LDLR, GYPA, HBGG, D7S8, and GC) genotypic and allelic frequencies are determined for a population sample of 102 unrelated Basque individuals using PCR-based methodology. All six loci met Hardy-Weinberg expectations in at least two of the three analyses performed (HLA-DQA1 failed to meet Hardy-Weinberg requirements in the heterozygote deficiency test). Three linkage analysis programs (GDA, GENEPOP and LINKDOS) detected possible linkage disequilibrium between LDLR and HBGG and results from one (GDA) indicated a possible non-random association between HBGG and HLA-DQA1 as well. Allelic data for the six loci are compared to that previously established for other populations (18 for polymarker alone, 16 for polymarker plus HLA-DQA1) to determine homogeneity between the Basque sample and these groups. According to the results of G-tests based on these loci, the Tadjik, a nomadic Caucasian group from western Asia, and the Basque residents are the only sample populations surveyed that are homogenous with the Basque sample. Phylogenetic analysis places the Basque sample correctly within the Caucasian cluster.

Jordanian population data on the PCR-based loci: LDLR, GYPA, HBGG, D7S8 and GC

Genotype and allele frequency distributions for PM polymerase chain reaction (PCR)-based genetic markers were determined in a Jordanian sample population. Results were obtained using the AmpliType PM PCR Amplification and typing kit. All loci were in agreement with the Hardy-Weinberg equilibrium expectations. The predominant alleles for LDLR, GYPA, HBGG, D7S8 and GC loci were B, A, B, A and C respectively. No statistically significant variation was detected in allele frequencies of these loci in Jordanians compared to that in Israeli Arab, U.S Caucasian and Japanese populations. Data presented here can be used to estimate the frequency of a specific DNA profile in the Jordanian population for forensic analyses and paternity testing.

HLA DQ alpha genotype and allele frequencies in Qatari population

Genotype and allele frequencies of HLA DQ alpha locus were determined in a Qatari population sample using polymerase chain reaction (PCR) amplified DNA fragment and hybridization to allele specific oligonucleoid probes in a reversed dot blot format. Among the 200 individuals studied 21 genotypes representing products of 6 HLA DQ alpha alleles have been differentiated, and the frequencies ranged from 0.0775 to 0.2825. The observed and expected genotypes values provide a complete fit to the Hardy-Weinberg equilibrium. The power of discrimination is 0.9321 and chance of paternity exclusion is 60.9% in the Qatari population.

Distribution of HLA-DQA1 alleles in Arab and Pakistani individuals from Dubai, United Arab Emirates

PCR-based typing of the HLA-DQA1 locus, using allele specific oligonucleotide (ASO) probes and reverse dot blot methodology was used to determine allelic distributions and construct a database for Arab and Pakistani individuals living in Dubai. Genotype and allelic frequencies were calculated, and the data were tested for departures from Hardy-Weinberg (HWE) equilibrium. The most frequent HLA-DQA1 alleles among Dubaian Arabs are DQA1 4 and 1.2. Among Pakistanis, the most frequent allele is also DQA1 4. No significant deviations from HWE were detected.

Frequencies of the five PCR-based genetic markers LDLR, GYPA, HBGG, D7S8 and GC in the population of Asturias (North Spain)

Allele and genotype frequencies of the loci LDLR, GYPA, HBGG, D7S8 and GC (PM loci) were investigated in a population sample of 215 unrelated individuals from Asturias (North Spain). Multiplex amplification and simultaneous typing of the five loci was carried out using the polymarker PCR amplification and typing kit. All loci met Hardy-Weinberg expectations. The Asturian sample does not differ significantly from other Caucasians, but significant differences were observed between this population and SW Hispanic, Afro-american and Korean populations.

Population data on the PCR-based loci LDLR GYPA, HBGG, D7S8, Gc, HLA-DQA1, and D1S80 from Arabs from Dubai

Population data were generated for the loci LDLR, GYPA, HBGG, D7S8, Gc, HLA-DQA1, and D1S80 from 180 Arabs from Dubai. Except for D7S8 (P = 0.003), the genotype frequency distributions for the loci do not deviate from Hardy Weinberg expectations. There was no evidence for departures from expectations of independence between the loci. Using a test for homogeneity, the loci LDLR, GYPA, D7S8, and Gc were similar between the Dubaian Arab population sample and an Arab population sample from Palestine and the occupied territories, while the loci HBGG (P = 0.003), DQA1 (P < 10(-3)), and D1S80 (P = 0.020) were statistically different.

Human phylogenetic relationships according to the D1S80 locus

By analyzing the allelic frequencies at the D1S80 locus in 43 human populations, we show that the locus is polymorphic globally and that it can be used to discriminate between major racial groups and subpopulations through phylogenetic analysis. Although the use of informative multiple loci generally provides more accurate phylogenetic relationships, in instances where time and/or target DNA availability is limited, D1S80 could provide useful data to discriminate between human groups. Also, knowledge of which loci independently provide accurate phylogenetic relationships, such as the D1S80, can be used to design more accurate multi-locus combinations. In addition, allele frequencies at the locus are reported, for the first time, for Bahamian individuals of African origin and for Chimila, Bari, and Navajo (Cañoncito Valley) native Americans. Allelic data was obtained using standard polymerase chain reaction (PCR) techniques. In the four new populations, 65 genotypes and 20 segregating alleles were observed. All populations conformed to Hardy-Weinberg expectations except the Chimila.