The pilot study of the phasing method for STR haplotypes / 中国法医学杂志

Referring to the statistical model for the SNP haplotype phasing which was based on the allele frequencies and advised by Browning SR, we investigated and deduced the phasing method of STR haplotype with linkage disequilibrium inpaternity testing preliminarily. Haplotype phasing of two X-STRs in linkage disequilibrium were illustrated. This method provides an idea for the haplotype phasing of STR markers, which is helpful for interpreting the typing results of STR more scientifically and accurately.

Short Reads Phasing to Construct Haplotypes in Genomic Regions That Are Associated with Body Mass Index in Korean Individuals

Genome-wide association (GWA) studies have found many important genetic variants that affect various traits. Since these studies are useful to investigate untyped but causal variants using linkage disequilibrium (LD), it would be useful to explore the haplotypes of single-nucleotide polymorphisms (SNPs) within the same LD block of significant associations based on high-density variants from population references. Here, we tried to make a haplotype catalog affecting body mass index (BMI) through an integrative analysis of previously published whole-genome next-generation sequencing (NGS) data of 7 representative Korean individuals and previously known Korean GWA signals. We selected 435 SNPs that were significantly associated with BMI from the GWA analysis and searched 53 LD ranges nearby those SNPs. With the NGS data, the haplotypes were phased within the LDs. A total of 44 possible haplotype blocks for Korean BMI were cataloged. Although the current result constitutes little data, this study provides new insights that may help to identify important haplotypes for traits and low variants nearby significant SNPs. Furthermore, we can build a more comprehensive catalog as a larger dataset becomes available.

SAD phasing with in-house Cu Kα radiation using barium as anomalous scatterer.

Phasing of lysozyme crystals using co-crystallized barium ions was performed using single-wavelength anomalous diffraction (SAD) method using Cu Kα radiation with in-house source of data collection. As the ion binding sites vary with respect to the pH of the buffer during crystallization, the highly isomorphic forms of lysozyme crystals grown at acidic and alkaline pH were used for the study. Intrinsic sulphur anomalous signal was also utilized with anomalous signal from lower occupancy ions for phasing. The study showed that to solve the structure by SAD technique, 2.8-fold data redundancy was sufficient when barium was used as an anomalous marker in the in-house copper X-ray radiation source for data collection. Therefore, co-crystallization of proteins with barium containing salt can be a powerful tool for structure determination using lab source.

A Program for Efficient Phasing of Three-Generation Trio SNP Genotype Data

Here, we report a computer program written in Python, which phases SNP genotypes and infers inherited deletions based on the pattern of Mendelian inheritance within a trio pedigree. When tiered trio genotypes that encompass three generations are available, it narrows a recombination event down to a region between two consecutive heterozygous markers. In addition, the phase information that is inferred from the upper trio that is formed by one of the parents and grandparents can be propagated to phase the genotypes of the lower trio that is formed by the parents and an offspring.