In silico prediction of high-resolution Hi-C interaction matrices

The three-dimensional (3D) organization of the genome plays an important role in gene regulation bringing distal sequence elements in 3D proximity to genes hundreds of kilobases away. Hi-C is a powerful genome-wide technique to study 3D genome organization. Owing to experimental costs, high resolution Hi-C datasets are limited to a few cell lines. Computational prediction of Hi-C counts can offer a scalable and inexpensive approach to examine 3D genome organization across multiple cellular contexts. Here we present HiC-Reg, an approach to predict contact counts from one-dimensional regulatory signals. HiC-Reg predictions identify topologically associating domains and significant interactions that are enriched for CCCTC-binding factor (CTCF) bidirectional motifs and interactions identified from complementary sources. CTCF and chromatin marks, especially repressive and elongation marks, are most important for HiC-Reg’s predictive performance. Taken together, HiC-Reg provides a powerful framework to generate high-resolution profiles of contact counts that can be used to study individual locus level interactions and higher-order organizational units of the genome.

Gaussian Fuzzy Number for STR-DNA Similarity Calculation Involving Familial and Tribal Relationships

We performed locus similarity calculation by measuring fuzzy intersection between individual locus and reference locus and then performed CODIS STR-DNA similarity calculation. The fuzzy intersection calculation enables a more robust CODIS STR-DNA similarity calculation due to imprecision caused by noise produced by PCR machine. We also proposed shifted convoluted Gaussian fuzzy number (SCGFN) and Gaussian fuzzy number (GFN) to represent each locus value as improvement of triangular fuzzy number (TFN) as used in previous research. Compared to triangular fuzzy number (TFN), GFN is more realistic to represent uncertainty of locus information because the distribution is assumed to be Gaussian. Then, the original Gaussian fuzzy number (GFN) is convoluted with distribution of certain ethnic locus information to produce the new SCGFN which more represents ethnic information compared to original GFN. Experiments were done for the following cases: people with family relationships, people of the same tribe, and certain tribal populations. The statistical test with analysis of variance (ANOVA) shows the difference in similarity between SCGFN, GFN, and TFN with a significant level of 95%. The Tukey method in ANOVA shows that SCGFN yields a higher similarity which means being better than the GFN and TFN methods. The proposed method enables CODIS STR-DNA similarity calculation which is more robust to noise and performed better CODIS similarity calculation involving familial and tribal relationships.

Activation of individual L1 retrotransposon instances is restricted to cell-type dependent permissive loci

LINE-1 (L1) retrotransposons represent approximately one sixth of the human genome, but only the human-specific L1HS-Ta subfamily acts as an endogenous mutagen in modern humans, reshaping both somatic and germline genomes. Due to their high levels of sequence identity and the existence of many polymorphic insertions absent from the reference genome, the transcriptional activation of individual genomic L1HS-Ta copies remains poorly understood. Here we comprehensively mapped fixed and polymorphic L1HS-Ta copies in 12 commonly-used somatic cell lines, and identified transcriptional and epigenetic signatures allowing the unambiguous identification of active L1HS-Ta copies in their genomic context. Strikingly, only a very restricted subset of L1HS-Ta loci - some being polymorphic among individuals - significantly contributes to the bulk of L1 expression, and these loci are differentially regulated among distinct cell lines. Thus, our data support a local model of L1 transcriptional activation in somatic cells, governed by individual-, locus-, and cell-type-specific determinants.

Comparative efficacy of four candidate DNA barcode regions for identification of Vicia species

The genus Vicia L., one of the earliest domesticated plant genera, is a member of the legume tribe Fabeae of the subfamily Papilionoideae (Fabaceae). The taxonomic history of this genus is extensive and controversial, which has hindered the development of taxonomic procedures and made it difficult to identify and share these economically important crop resources. Species identification through DNA barcoding is a valuable taxonomic classification tool. In this study, four DNA barcodes (ITS2, matK, rbcL and psbA-trnH) were evaluated on 110 samples that represented 34 taxonomically best-known species in the Vicia genus. Topologies of the phylogenetic trees based on an individual locus were similar. Individual locus-based analyses could not discriminate closely related Vicia species. We proposed a concatenated data approach to increase the resolving power of ITS2. The DNA barcodes matK, psbA-trnH and rbcL were used as an additional tool for phylogenetic analysis. Among the four barcodes, three-barcode combinations that included psbA-trnH with any two of the other barcodes (ITS2, matK or rbcL) provided the best discrimination among Vicia species. Species discrimination was assessed with bootstrap values and considered successful only when all the conspecific individuals formed a single clade. Through sequencing of these barcodes from additional Vicia accessions, 17 of the 34 known Vicia species could be identified with varying levels of confidence. From our analyses, the combined barcoding markers are useful in the early diagnosis of targeted Vicia species and can provide essential baseline data for conservation strategies, as well as guidance in assembling germplasm collections.

Evidence for a genetic basis of urogenital carcinoma in the wild California sea lion

Although neoplasia is a major cause of mortality in humans and domestic animals, it has rarely been described in wildlife species. One of the few examples is a highly prevalent urogenital carcinoma in California sea lions (CSLs). Although the aetiology of this carcinoma is clearly multifactorial, inbreeding depression, as estimated using levels of microsatellite multilocus heterozygosity, is identified as predictive for this neoplasia. On further analysis, this relationship appears to be largely driven by one marker, suggesting that a single locus might be associated with the occurrence of this disease in CSLs. In a case–control study, carcinoma was significantly associated with homozygosity at the Pv11 microsatellite locus. Pv11 was mapped to intron 9 of the heparanase 2 gene ( HPSE2 ) locus, a very large gene encoding heparanase 2, which in humans is associated with multiple carcinomas. Correspondingly, immunohistochemical labelling in tissues was present in carcinoma cases within a single homozygous Pv11 genotype. To our knowledge, this is the first report of an individual locus being associated with cancer in any wildlife species. This adds emphasis to the study of HPSE2 in other species, including humans and will guide future studies on this sentinel species that shares much of its diet and environment with humans

Analysis of the Microsatellite Variation in the Common Hybrid Between Russian Sturgeon (Acipenser Gueldenstaedtii Brandt and Ratzeburg, 1833) and Siberian Sturgeon (Acipenser Baerii Brandt, 1869) from Aquaculture

ABSTRACT Sturgeons such as Acipenser baerii and Acipenser gueldenstaedtii are the most common species farm raised worldwide in aquaculture, because of the dwindling natural sources of caviar and meat. Also, these species can easily participate in the formation of an intraspecific hybrid with a great potential for growth in aquaculture. Microsatellites are nuclear markers consisting of short repetitive sequence, dispersed across the entire genome with characteristics such as relatively small size and high level of polymorphism. The aims of the present study were to optimize a protocol for microsatellite multiplexing and analysis of genetic diversity in hybrid sturgeons farmed in Romania. Genomic DNA was isolated from fins, and four pairs of primers were designed to amplify microsatellite loci: LS 19, LS 68, Aox 9, and Aox 45. Amplification of the microsatellite loci was carried out in one 3-Plex reaction for LS 19, LS 68, and Aox 9, and monoplex reaction for Aox 45. For an individual locus we obtained four alleles for Aox 45, eleven alleles for Aox 9, six alleles for LS 68, and eight alleles for LS 19. The results will be applied to test the broodstocks at Romanian hatcheries and to increase the efficiency of breeding.