Jiangwei Yan

Application of Next-generation Sequencing Technology in Forensic Science

Next-generation sequencing (NGS) technology, with its high-throughput capacity and low cost, has developed rapidly in recent years and become an important analytical tool for many genomics researchers. New opportunities in the research domain of the forensic studies emerge by harnessing the power of NGS technology, which can be applied to simultaneously analyzing multiple loci of forensic interest in different genetic contexts, such as autosomes, mitochondrial and sex chromosomes. Furthermore, NGS technology can also have potential applications in many other aspects of research. These include DNA database construction, ancestry and phenotypic inference, monozygotic twin studies, body fluid and species identification, and forensic animal, plant and microbiological analyses. Here we review the application of NGS technology in the field of forensic science with the aim of providing a reference for future forensics studies and practice.

Transcriptome dynamics during human erythroid differentiation and development

To explore the mechanisms controlling erythroid differentiation and development, we analyzed the genome-wide transcription dynamics occurring during the differentiation of human embryonic stem cells (HESCs) into the erythroid lineage and development of embryonic to adult erythropoiesis using high throughput sequencing technology. HESCs and erythroid cells at three developmental stages: ESER (embryonic), FLER (fetal), and PBER (adult) were analyzed. Our findings revealed that the number of expressed genes decreased during differentiation, whereas the total expression intensity increased. At each of the three transitions (HESCs-ESERs, ESERs-FLERs, and FLERs-PBERs), many differentially expressed genes were observed, which were involved in maintaining pluripotency, early erythroid specification, rapid cell growth, and cell-cell adhesion and interaction. We also discovered dynamic networks and their central nodes in each transition. Our study provides a fundamental basis for further investigation of erythroid differentiation and development, and has implications in using ESERs for transfusion product in clinical settings.

Whole transcriptome RNA-seq analysis: tumorigenesis and metastasis of melanoma

Melanoma is the most malignant cutaneous cancer and causes over 9000 deaths annually. Because fatality rates from malignant melanoma (MM) increase dramatically upon metastasis, we investigated tumorigenesis and metastasis of MM in transcriptome analyses of three distinct cell lines that correspond with the stages of MM pathogenesis: the normal stage (HEMn-LP), the onset of MM (A375), and the metastasis stage (A2058). Using next-generation sequencing (NGS) technology, we detected asymmetrical expression of genes among the three cell lines, notably on chromosomes 9, 11, 12, and 14, suggesting their involvement in tumorigenesis and metastasis of MM. These genes were clustered into 41 categories based on their expression patterns, and their biological functions were analyzed using Ingenuity Pathway Analysis. In the top cancer-associated category, HIF1A, IL8, TERT, ONECUT1, and FOXA1 directly interacted with either transcription factors or cytokines that are known to be involved in the tumorigenesis or metastasis of other malignant tumors. The present data suggest that cytokine regulatory pathways in macrophages predominate over other pathways during the pathogenesis of MM. This study provides new targets for the downstream mechanistic studies of the tumorigenesis and metastasis of MM and demonstrates a new strategy for studies of the progression of other malignant cancers.

Characterization of miRNomes in Acute and Chronic Myeloid Leukemia Cell Lines

Myeloid leukemias are highly diverse diseases and have been shown to be associated with microRNA (miRNA) expression aberrations. The present study involved an in-depth miRNome analysis of two human acute myeloid leukemia (AML) cell lines, HL-60 and THP-1, and one human chronic myeloid leukemia (CML) cell line, K562, via massively parallel signature sequencing. mRNA expression profiles of these cell lines that were established previously in our lab facilitated an integrative analysis of miRNA and mRNA expression patterns. miRNA expression profiling followed by differential expression analysis and target prediction suggested numerous miRNA signatures in AML and CML cell lines. Some miRNAs may act as either tumor suppressors or oncomiRs in AML and CML by targeting key genes in AML and CML pathways. Expression patterns of cell type-specific miRNAs could partially reflect the characteristics of K562, HL-60 and THP-1 cell lines, such as actin filament-based processes, responsiveness to stimulus and phagocytic activity. miRNAs may also regulate myeloid differentiation, since they usually suppress differentiation regulators. Our study provides a resource to further investigate the employment of miRNAs in human leukemia subtyping, leukemogenesis and myeloid development. In addition, the distinctive miRNA signatures may be potential candidates for the clinical diagnosis, prognosis and treatment of myeloid leukemias.

Dynamic transcriptomes of human myeloid leukemia cells

To identify the mechanisms controlling chronic myeloid leukemia (CML) and acute myeloid leukemia (AML) in humans, we analyzed genome-wide transcription dynamics in three myeloid leukemia cell lines (K562, HL-60, and THP1) using high-throughput sequencing technology. Using KEGG analysis, we found that the ERK/MAPK, JAK-STAT and ErbB pathways promoted proliferation and metabolism in CML. However, in AML, differentiation and apoptosis blocking resulted in the accumulation of blast cells in marrow. In addition, each cell type had unique characteristics. K562 cells are an ideal model for studying erythroid differentiation and globin gene expression. The chemokine signaling pathway and Fc gamma R-mediated phagocytosis were markedly upregulated in HL-60 cells. In THP1 cells, highly expressed genes ensured strong phagocytosis by monocytes. Further, we provide a new insight into myeloid development. The abundant data sets and well-defined analysis methods will provide a resource and strategy for further investigation of myeloid leukemia.

Genetic Analysis of 15 STR Loci in Chinese Han Population from West China

Allele frequencies for 15 short tandem repeat (STR) loci (D8S1179, D21S11, D7S820, CSF1PO, D3S1358, TH01, D13S317, D16S539, D2S1338, D19S433, vWA, TPOX, D18S51, D5S818, and FGA) were obtained from 7,636 unrelated individuals of Chinese Han population living in Qinghai and Chongqing, China. Totally 206 alleles were observed, with the corresponding allele frequencies ranging from 0.0001–0.4982. Chi-square test showed that all of the STR loci agreed with the Hardy-Weinberg equilibrium. We also compared our data with previously published population data of other ethnics or areas. The results are valuable for human identification and paternity testing in Chinese Han population.

Genetic diversity and haplotypic structure of Chinese Kazak ethnic group revealed by 19 STRs on the X chromosome

X-chromosomal short tandem repeats (X-STRs) have been widely used in forensic practices involving complicated ties of kinship over the past years, and also play an increasingly important role in population genetics. To study the genetic polymorphisms of 19 STR loci on X chromosome in Chinese Kazak ethnic group, we investigated the allelic and haplotypic frequencies of the 19 loci in 300 (149 males and 151 females) unrelated healthy individuals from Ili Kazak Autonomous Prefecture, Xinjiang Uigur Autonomous Region of China after having evaluated the forensic application value of these loci in forensic sciences, and then compared the population distinctions between the Kazak group and other reference groups. We observed a total of 240 alleles at these X-STR loci with the corresponding allelic frequencies ranging from 0.0017 to 0.5917. In the study, the highest polymorphism was found at DXS10135 locus. The combined power of discrimination in females was 0.999999999999999999999985 and in males 0.999999999999968. The present study indicates that the 19 X-STR loci are very useful for both forensic identification cases and kinship analyses involving a female offspring.

Genetic variation and forensic efficiency of autosomal insertion/deletion polymorphisms in Chinese Bai ethnic group: phylogenetic analysis to other populations

Thirty insertion/deletion loci were utilized to study the genetic diversities of 125 bloodstain samples collected from Bai group in Yunnan Dali region, China. The observed heterozygosity and expected heterozygosity of the 30 loci ranged from 0.1520 to 0.5680, and 0.1927 to 0.4997, respectively. No deviations from Hardy-Weinberg equilibrium tests after Bonferroni correction were found at all 30 loci in Bai group. The cumulative probability of exclusion and combined discrimination power were 0.9859 and 0.9999999999887, respectively, which indicated the 30 loci could be used as complementary genetic markers for paternity testing and were qualified for personal identification in forensic cases. We found the studied Bai group had close relationships with Tibetan, Yi and Han groups from China by the population structure, principal component analysis, population differentiations, and phylogenetic reconstruction studies. Even so, for a better understanding of Bai ethnicitys genetic milieu, DNA genotyping at various genetic markers is necessary in future studies.

Study of genetic diversity of killer cell immunoglobulin-like receptor loci in the Tujia ethnic minority

The aim of this study was to analyze the genetic profiles of 14 killer cell immunoglobulin-like receptor (KIR) genes and 2 pseudogenes of 124 individuals from Tujia ethnic minority residing in Enshi Tujia and Miao autonomous prefecture of Hubei province of China and investigate the genetic relationships between the Tujia ethnic minority and other reported groups for the first time. Sequence specific primer amplification (PCR-SSP) methods were used to genotype the 14 KIR genes and 2 pseudogenes. The observed carrier frequencies (OF) and the gene frequencies (GF) of the KIR genes were measured. Neighbor-joining (N-J) tree and the principal component analysis (PCA) plot were constructed. All individuals were typed positive for the three framework loci KIR3DL3, 2DL4 and 3DL2, as well as for pseudogene KIR3DP1. The gene frequencies of the other KIR genes ranged from 9% in KIR2DS2 to 98% in KIR2DP1 and KIR3DL1. The present study of the KIR genes may be a powerful tool for enriching the Chinese ethnical gene information resources of the KIR gene pool, as well as for the anthropological research.

Concurrent copy number variations on chromosome 8 and 22 combined with mutation at FGA locus revealed in a parentage testing case

Copy number variations (CNVs) are one of the major sources of human genetic diversity and are associated with rare genomic disorders as well as complex traits and diseases. A copy number variation was observed at the D8S1179 locus during routine STR based parentage testing, in which the child exhibited three alleles, 13, 15, 16, with the putative father a homozygous 15 and the mother homozygous 13. In addition, in the same testing case, there was a one-step mutation at the STR locus FGA, in which the putative father was a 22, 24, the mother was a 22, 25, and the child was a 22, 23. After further investigations by re-amplified with different primer sets, clone-based sequencing, karyotype analysis and whole-genome SNP analysis, the results showed that the child had the CNVs at chromosome 8q24.3 and 22q11.21. In conclusion, for parentage testing cases encountered with tri-allele patterns, more testings, such as cloning sequencing, karyotyping, or even whole genome analysis, as well as more appropriate statistical estimations might be conducted to further confirm or exclude the relationship.