Search

Abstract 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.

Abstract 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.

Abstract 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.

Abstract Objective Navigation is the most important feature of homing pigeons, however no integrated response to genetic mechanism of navigation has been reported. The generated data herein represent whole-genome resequencing data for homing pigeon and three other breeds of rock pigeons. Selective sweep analysis between homing pigeon and other breeds of rock pigeon can provide new insight about identification of candidate genes and biological pathways for homing pigeon ability. Data description Whole-genomes sequence data related to 95 birds from four breeds of rock pigeons including, 29 feral pigeons, 24 Shiraz tumblers, 24 Persian high flyers and 18 homing pigeons were provided. More than 6.94 billion short reads with coverage (average ≈7.50 x) and 407.1 Gb data were produced. Whole genome sequencing was carried out on the Illumina Hiseq 2000 platform using a 350 bp library size and 150 bp paired-end read lengths. The whole genome sequencing data have been submitted at the NCBI SRA Database (PRJNA532675). The presented data set can provide useful genomic information to explain the genetic mechanism of navigation ability of homing pigeons and also testing other genetic hypothesis by genomic analysis.

Abstract Background Species domestication is generally characterized by the exploitation of high-impact mutations through processes that involve complex shifting demographics of domesticated species. These include not only inbreeding and artificial selection that may lead to the emergence of evolutionary bottlenecks, but also post-divergence gene flow and introgression. Although domestication potentially affects the occurrence of both desired and undesired mutations, the way wild relatives of domesticated species evolve and how expensive the genetic cost underlying domestication is remain poorly understood. Here, we investigated the demographic history and genetic load of chicken domestication. Results We analyzed a dataset comprising over 800 whole genomes from both indigenous chickens and wild jungle fowls. We show that despite having a higher genetic diversity than their wild counterparts (average π, 0.00326 vs. 0.00316), the red jungle fowls, the present-day domestic chickens experienced a dramatic population size decline during their early domestication. Our analyses suggest that the concomitant bottleneck induced 2.95% more deleterious mutations across chicken genomes compared with red jungle fowls, supporting the “cost of domestication” hypothesis. Particularly, we find that 62.4% of deleterious SNPs in domestic chickens are maintained in heterozygous states and masked as recessive alleles, challenging the power of modern breeding programs to effectively eliminate these genetic loads. Finally, we suggest that positive selection decreases the incidence but increases the frequency of deleterious SNPs in domestic chicken genomes. Conclusion This study reveals a new landscape of demographic history and genomic changes associated with chicken domestication and provides insight into the evolutionary genomic profiles of domesticated animals managed under modern human selection.