Genomic analysis reveals variant association with high altitude adaptation in native chickens

Quantitative Assessment of PALB2 and BRIP1 Genes Expression in the Breast Cancer Cell Line under the Influence of Tamoxifen

BACKGROUND

Breast cancer is considered one of the leading causes of mortality in the world. Cancer incidence and consequently, drug consumption can strongly influence gene expressions at the transcriptome level. Therefore, the assessment of the candidate biomarkers' gene expression can accelerate the diagnosis process and increase the chance of treatment and remission. In this regard, the quantitative assessment of Partner and localizer of BRCA2 (PALB2) and BRCA1 Interacting Helicase 1 (BRIP1) genes expression in the breast cancer cell line under the treatment of Tamoxifen (TAM) was executed in this study.

MATERIALS AND METHODS

MCF7 cells were cultured as TAM-treated and control groups. RNA extraction and cDNA synthesis were performed based on the instructions of provided kits. qPCR Hi-ROX Master Mix kit was applied to the quantitative real-time polymerase chain reaction (Q-PCR). The outputs of Q-PCR were analyzed by REST statistical software.

RESULTS

Outcomes derived from data analysis of BRIP1 gene expression did not show any significant difference between the gene expression of control and TAM-treated groups. The expression of PALB2 was significantly higher in the TAM-treated group compared to the control group (P0.05).

CONCLUSION

Our findings showed a significant alteration between PALB2 gene expression in the TAM-treated breast cancer cell line and the control cell line. The quantitative assessment of mentioned genes as possible markers could be considered a non-invasive method for breast cancer in the processes of prognostic evaluations, screening, and treatment monitoring.

Novel genetic variants data for adaptation to hypoxia in native chickens

OBJECTIVE

The genomic response and the role of genetic variants in hypoxia condition are always interesting issues about adaption pathways at genomic level. Herein, we carried out a comparative genomic study between highland and lowland native chickens, in order to identify the adaptive variants in hypoxia condition. We generated more than 20 million genetic variants in highland and lowland chickens. Finally, 3877 SNVs including the mtDNA ones, were discovered as novel adaptive genetic variants. The generated data set can provide new insight about mechanism of adaptation to hypoxia at genomic level.

DATA DESCRIPTION

To investigate the role of genetic variants in adaptation to hypoxia, 10 whole-genome sequencing data sets associated to highland and lowland native chickens were provided. DNA was extracted by salting-out protocol. Paired-end 125 bp short reads were sequenced by Illumina Hiseq 2000. Variants calling of highland and lowland native chickens were performed by fix ploidy algorithm in CLC Genomic Workbench. Total genetic variants of highland chickens were compared to lowland chickens in order to identify the differential genetic variants (DGVs) between highland and lowland chickens. In this way, 3877 novel SNVs (VCF format) including the mtDNA ones, were deposited at EBI database ( https://identifiers.org/ena.embl:ERZ491574 ) for the first time.

The study of selection signature and its applications on identification of candidate genes using whole genome sequencing data in chicken - a review

Chicken is a major source of protein for the increasing human population and is useful for research purposes. There are almost 1,600 distinct regional breeds of chicken across the globe, among which a large body of genetic and phenotypic variations has been accumulated due to extensive natural and artificial selection. Moreover, natural selection is a crucial force for animal domestication. Several approaches have been adopted to detect selection signatures in different breeds of chicken using whole genome sequencing (WGS) data including integrated haplotype score (iHS), cross-populated extend haplotype homozygosity test (XP-EHH), fixation index (F_ST), cross-population composite likelihood ratio (XP-CLR), nucleotide diversity (Pi), and others. In addition, gene enrichment analyses are utilized to determine KEGG pathways and gene ontology (GO) terms related to traits of interest in chicken. Herein, we review different studies that have adopted diverse approaches to detect selection signatures in different breeds of chicken. This review systematically summarizes different findings on selection signatures and related candidate genes in chickens. Future studies could combine different selection signatures approaches to strengthen the quality of the results thereby providing more affirmative inference. This would further aid in deciphering the importance of selection in chicken conservation for the increasing human population.

Key miRNAs and Genes in the High-Altitude Adaptation of Tibetan Chickens

Tibetan chickens living at high altitudes show specific physiological adaptations to the extreme environmental conditions. However, the regulated base of how chickens adapt to high-altitude habitats remains largely unknown. In this study, we sequenced 96 transcriptomes (including 48 miRNA and 48 mRNA transcriptomes of heart, liver, lung, and brain) and resequenced 12 whole genomes of Tibetan chickens and Peng'xian yellow chickens. We found that several miRNAs show the locally optimal plastic changes that occurred in miRNAs of chickens, such as miR-10c-5p, miR-144-3p, miR-3536, and miR-499-5p. These miRNAs could have effects on early adaption to the high-altitude environment of chickens. In addition, the genes under selection between Tibetan chickens and Peng'xian yellow chickens were mainly related to oxygen transport and oxidative stress. The I-kappa B kinase/NF-kappa B signaling pathway is widely found for high-altitude adaptation in Tibetan chickens. The candidate differentially expressed miRNAs and selected genes identified in this study may be useful in current breeding efforts to develop improved breeds for the highlands.

Comparative analysis of long noncoding RNA and mRNA expression provides insights into adaptation to hypoxia in Tibetan sheep

Tibetan sheep have lived on the Qinghai-Tibetan Plateau for thousands of years and have good adaptability to the hypoxic environment and strong disease resistance. However, the molecular mechanism by which Tibetan sheep adapt to this extreme environment, especially the role of genetic regulation, is still unknown. Emerging evidence suggests that long noncoding RNAs (lncRNAs) participate in the regulation of a diverse range of biological processes. To explore the potential lncRNAs involved in the adaptation to high-altitude hypoxia of Tibetan sheep, we analysed the expression profile of lncRNAs and mRNAs in the liver and lung tissues of sheep using comparative transcriptome analysis between four Tibetan sheep populations (high altitude) and one Hu sheep population (low altitude). The results showed a total of 7848 differentially expressed (DE) lncRNA transcripts, and 22,971 DE mRNA transcripts were detected by pairwise comparison. The expression patterns of selected mRNAs and lncRNAs were validated by qRT-PCR, and the results correlated well with the transcriptome data. Moreover, the functional annotation analysis based on the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases showed that DE mRNAs and the target genes of the lncRNAs were significantly enriched in organ morphogenesis, response to stimulus, haem binding, the immune system, arginine and proline metabolism, and fatty acid biosynthesis. The prediction of mRNA–mRNA and lncRNA–mRNA interaction networks further revealed transcripts potentially involved in adaptation to high-altitude hypoxia, and the hub genes DDX24, PDCD11, EIF4A3, NDUFA11, SART1, PRPF8 and TCONS_00306477, TCONS_00306029, TCONS_00139593, TCONS_00293272, and TCONS_00313398 were selected. Additionally, a set of target genes, PIK3R1, IGF1R, FZD6, IFNB2, ATF3, MB, CYP2B4, PSMD13, and TGFB1, were also identified as candidate genes associated with high-altitude hypoxia adaptation. In conclusion, a collection of novel expressed lncRNAs, a set of target genes and biological pathways known to be relevant for altitude adaptation were identified by comparative transcriptome analysis between Tibetan sheep and Hu sheep. Our results are the first to identify the characterization and expression profile of lncRNAs between Tibetan sheep and Hu sheep and provide insights into the genetic regulation mechanisms by which Tibetan sheep adapt to high-altitude hypoxic environments.

Transcriptome resequencing data for rock pigeon (Columba livia)

OBJECTIVE

How do birds navigate their way? It is one of the interesting question about homing pigeons, however the genetic of navigation has reminded as a puzzle. Optic lobe, olfactory bulb, hippocampus and cere were collected for RNA sampling. The generated RNA-seq represent RNA resequencing data for racing homer (homing) pigeon and other rock pigeon breeds. The obtained data set can provide new insight about hippocampus role and GSR contribution to pigeon magnetoreception.

DATA DESCRIPTION

To investigate the navigation ability of rock pigeon breeds, 60 whole transcriptome sequence data sets related to homing pigeon, Shiraz tumblers, feral pigeons and Persian high flyers were obtained. RNA extraction was performed from three brain regions (optic lobe, olfactory bulb, hippocampus) and cere. Paired-end 150 bp short reads (Library size 350 bp) were sequenced by Illumina Hiseq 2000. In this way, about 342.1 Gbp and 130.3 Gb data were provided. The whole transcriptome data sets have been deposited at the NCBI SRA database (PRJNA532674). The submitted data set may play critical role to describe the mechanism of navigation ability of rock pigeon breeds.

Genetic diversity and signatures of selection for heat tolerance and immune response in Iranian native chickens

Background

Understanding how evolutionary forces relating to climate have shaped the patterns of genetic variation within and between species is a fundamental pursuit in biology. Iranian indigenous chickens have evolved genetic adaptations to their local environmental conditions, such as hot and arid regions. In the present study, we provide a population genome landscape of genetic variations in 72 chickens representing nine Iranian indigenous ecotypes (Creeper, Isfahan, Lari, Marand, Mashhad, Naked neck, Sari, Shiraz and Yazd) and two commercial lines (White Leghorn and Arian). We further performed comparative population genomics to evaluate the genetic basis underlying variation in the adaptation to hot climate and immune response in indigenous chicken ecotypes. To detect genomic signatures of adaptation, we applied nucleotide diversity (θπ) and F_ST statistical measurements, and further analyzed the results to find genomic regions under selection for hot adaptation and immune response-related traits.

Results

By generating whole-genome data, we assessed the relationship between the genetic diversity of indigenous chicken ecotypes and their genetic distances to two different commercial lines. The results of genetic structure analysis revealed clustering of indigenous chickens in agreement with their geographic origin. Among all studied chicken groups, the highest level of linkage disequilibrium (LD) (~ 0.70) was observed in White Leghorn group at marker pairs distance of 1 Kb. The results from admixture analysis demonstrated evidence of shared ancestry between Arian individuals and indigenous chickens, especially those from the north of the country. Our search for potential genomic regions under selection in indigenous chicken ecotypes revealed several immune response and heat shock protein-related genes, such as HSP70, HSPA9, HSPH1, HSP90AB1 and PLCB4 that have been previously unknown to be involved in environmental-adaptive traits. In addition, we found some other candidate loci on different chromosomes probably related with hot adaptation and immune response-related traits.

Conclusions

The work provides crucial insights into the structural variation in the genome of Iranian indigenous chicken ecotypes, which up to now has not been genetically investigated. Several genes were identified as candidates for drought, heat tolerance, immune response and other phenotypic traits. These candidate genes may be helpful targets for understanding of the molecular basis of adaptation to hot environmental climate and as such they should be used in chicken breeding programs to select more efficient breeds for desert climate.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-022-08434-7.

Landscape genomics of the streamside salamander: Implications for species management in the face of environmental change

Understanding spatial patterns of genetic differentiation and local adaptation is critical in a period of rapid environmental change. Climate change and anthropogenic development have led to population declines and shifting geographic distributions in numerous species. The streamside salamander, Ambystoma barbouri, is an endemic amphibian with a small geographic range that predominantly inhabits small, ephemeral streams. As A. barbouri is listed as near-threatened by the IUCN, we describe range-wide patterns of genetic differentiation and adaptation to assess the species' potential to respond to environmental change. We use outlier scans and genetic-environment association analyses to identify genomic variation putatively underlying local adaptation across the species' geographic range. We find evidence for adaptation with a polygenic architecture and a set of candidate SNPs that identify genes putatively contributing to local adaptation. Our results build on earlier work that suggests that some A. barbouri populations are locally adapted despite evidence for asymmetric gene flow between the range core and periphery. Taken together, the body of work describing the evolutionary genetics of range limits in A. barbouri suggests that the species may be unlikely to respond naturally to environmental challenges through a range shift or in situ adaptation. We suggest that management efforts such as assisted migration may be necessary in future.

Using weighted gene co-expression network analysis (WGCNA) to identify the hub genes related to hypoxic adaptation in yak (Bos grunniens)

BACKGROUND

As a mammal living at the highest altitude in the world, the yak has strong adaptability to the harsh natural environment (such as low temperature, scarce food, especially low oxygen) of Qinghai-Tibet Plateau (QTP) after a long process of natural selection.

OBJECTIVE

Here, we used Weighted Correlation Network Analysis (WGCNA), a systematic biology method, to identify hypoxic adaptation-related modules and hub genes. The research of the adaptability of yak against hypoxia is of great significance to identify the genetic characteristics and yak breeding.

METHODS

Based on the transcriptome sequencing data (PRJNA362606), the R package DESeq2 and WGCNA were conducted to analyze differentially expressed genes (DEGs) and construct the gene co-expression network. The module hub genes were identified and characterized by the correlation of gene and trait, module membership (kME). In addition, GO and KEGG enrichment analyses were used to explore the functions of hub genes.

RESULTS

Our results revealed that 1098, 1429, and 1645 DEGs were identified in muscle, spleen, and lung, respectively. Besides, a total of 13 gene co-expression modules were detected, of which two hypoxic adaptation-related modules (saddlebrown and turquoise) were found. We identified 39 and 150 hub genes in these two modules. Functional enrichment analyses showed that 12 GO terms and 18 KEGG pathways were enriched in the saddlebrown module while 85 GO terms and 22 KEGG pathways were enriched in the turquoise module. The significant pathways related to hypoxia adaptation include FoxO signaling pathway, Thermogenesis pathway, and Retrograde endocannabinoid signaling pathway, etc. CONCLUSIONS: In this study, we obtained two hypoxia-related specific modules and identified hub genes based on the connectivity by constructing a weighted gene co-expression network. Function enrichment analysis of two modules revealed mitochondrion is the most important organelle for hypoxia adaptation. Moreover, the insulin-related pathways and thermogenic-related pathways played a major role. The results of this study provide theoretical guidance for further understanding the molecular mechanism of yak adaptation to hypoxia.

Gene network analysis to determine the effect of hypoxia-associated genes on brain damages and tumorigenesis using an avian model

BACKGROUND

Hypoxia refers to the condition of low oxygen pressure in the atmosphere and characterization of response to hypoxia as a biological complex puzzle, is challenging. Previously, we carried out a comparative genomic study by whole genome resequencing of highland and lowland Iranian native chickens to identify genomic variants associated with hypoxia conditions. Based on our previous findings, we used chicken as a model and the identified hypoxia-associated genes were converted to human's orthologs genes to construct the informative gene network. The main goal of this study was to visualize the features of diseases due to hypoxia-associated genes by gene network analysis.

RESULTS

It was found that hypoxia-associated genes contained several gene networks of disorders such as Parkinson, Alzheimer, cardiomyopathy, drug toxicity, and cancers. We found that biological pathways are involved in mitochondrion dysfunctions including peroxynitrous acid production denoted in brain injuries. Lewy body and neuromelanin were reported as key symptoms in Parkinson disease. Furthermore, calmodulin, and amyloid precursor protein were detected as leader proteins in Alzheimer's diseases. Dexamethasone was reported as the candidate toxic drug under the hypoxia condition that implicates diabetes, osteoporosis, and neurotoxicity. Our results suggested DNA damages caused by the high doses of UV radiation in high-altitude conditions, were associated with breast cancer, ovarian cancer, and colorectal cancer.

CONCLUSIONS

Our results showed that hypoxia-associated genes were enriched in several gene networks of disorders including Parkinson, Alzheimer, cardiomyopathy, drug toxicity, and different types of cancers. Furthermore, we suggested, UV radiation and low oxygen conditions in high-altitude regions may be responsible for the variety of human diseases.

Identifying Candidate Genes for Hypoxia Adaptation of Tibet Chicken Embryos by Selection Signature Analyses and RNA Sequencing

The Tibet chicken (Gallus gallus) lives on the Qinghai-Tibet Plateau and adapts to the hypoxic environment very well. The objectives of this study was to obtain candidate genes associated with hypoxia adaptation in the Tibet chicken embryos. In the present study, we used the fixation index (Fst) and cross population extended haplotype homozygosity (XPEHH) statistical methods to detect signatures of positive selection of the Tibet chicken, and analyzed the RNA sequencing data from the embryonic liver and heart with HISAT, StringTie and Ballgown for differentially expressed genes between the Tibet chicken and White leghorn (Gallus gallus, a kind of lowland chicken) embryos hatched under hypoxia condition. Genes which were screened out by both selection signature analysis and RNA sequencing analysis could be regarded as candidate genes for hypoxia adaptation of chicken embryos. We screened out 1772 genes by XPEHH and 601 genes by Fst, and obtained 384 and 353 differentially expressed genes in embryonic liver and heart, respectively. Among these genes, 89 genes were considered as candidate genes for hypoxia adaptation in chicken embryos. ARNT, AHR, GSTK1 and FGFR1 could be considered the most important candidate genes. Our findings provide references to elucidate the molecular mechanism of hypoxia adaptation in Tibet chicken embryos.