Meixia Fang

The genetic effects of the dopamine D1 receptor gene on chicken egg production and broodiness traits.

BackgroundThe elevation of egg production and the inhibition of incubation behavior are the aims of modern poultry production. Prolactin (PRL) gene is confirmed to be critical for the onset and maintenance of these reproductive behaviors in birds. Through PRL, dopamine D1 receptor (DRD1) was also involved in the regulation of chicken reproductive behavior. However, the genetic effects of this gene on chicken egg production and broodiness have not been studied extensively. The objective of this research was to evaluate the genetic effects of the DRD1 gene on chicken egg production and broodiness traits.ResultsIn this study, the chicken DRD1 gene was screened for the polymorphisms by cloning and sequencing and 29 variations were identified in 3,342 bp length of this gene. Seven single nucleotide polymorphism (SNPs) among these variations, including a non-synonymous mutation (A+505G, Ser169Gly), were located in the coding region and were chosen to analyze their association with chicken egg production and broodiness traits in 644 Ningdu Sanhuang individuals. Two SNPs, G+123A and C+1107T, were significantly associated with chicken broody frequency (P < 0.05). Significant association was also found between the G+1065A - C+1107T haplotypes and chicken broody frequency (P < 0.05). In addition, the haplotypes of G+123A and T+198C were significantly associated with weight of first egg (EW) (P = 0.03). On the other hand, the distribution of the DRD1 mRNA was observed and the expression difference was compared between broodiness and non-broodiness chickens. The DRD1 mRNA was predominantly expressed in subcutaneous fat and abdominal fat of non-broodiness chicken, and then in heart, kidney, oviduct, glandular stomach, hypothalamus, and pituitary. In subcutaneous fat and abdominal fat, the level of non-broodiness was 26 to 28 times higher than that of broodiness. In pituitary, it was 5-fold higher. In heart, oviduct, and kidney, a 2-3 times decrease from non-broodiness to broodiness was displayed. In glandular stomach and hypothalamus, the level seen in non-broodiness and broodiness was almost the same.ConclusionThe polymorphisms of the DRD1 gene and their haplotypes were associated with chicken broody frequency and some egg production traits. The mRNA distribution was significant different between broodiness and non-broodiness chickens.

Analysis of Muscle and Ovary Transcriptome of Sus scrofa: Assembly, Annotation and Marker Discovery

Pig (Sus scrofa) is an important organism for both agricultural and medical purpose. This study aims to investigate the S. scrofa transcriptome by the use of Roche 454 pyrosequencing. We obtained a total of 558 743 and 528 260 reads for the back-leg muscle and ovary tissue each. The overall 1 087 003 reads give rise to 421 767 341 bp total residues averaging 388 bp per read. The de novo assemblies yielded 11 057 contigs and 60 270 singletons for the back-leg muscle, 12 204 contigs and 70 192 singletons for the ovary and 18 938 contigs and 102 361 singletons for combined tissues. The overall GC content of S. scrofa transcriptome is 42.3% for assembled contigs. Alternative splicing was found within 4394 contigs, giving rise to 1267 isogroups or genes. A total of 56 589 transcripts are involved in molecular function (40 916), biological process (38 563), cellular component (35 787) by further gene ontology analyses. Comparison analyses showed that 336 and 553 genes had significant higher expression in the back-leg muscle and ovary each. In addition, we obtained a total of 24 214 single-nucleotide polymorphisms and 11 928 simple sequence repeats. These results contribute to the understanding of the genetic makeup of S. scrofa transcriptome and provide useful information for functional genomic research in future.

Transcriptome comparison in the pituitary-adrenal axis between Beagle and Chinese Field dogs after chronic stress exposure.

Chronic stress can induce a series of maladjustments, and the response to stress is partly regulated by the hypothalamus-pituitary-adrenal axis. The aim of this study was to investigate the genetic mechanisms of this axis regulating stress responsiveness. The pituitary and adrenal cortex of Beagle and Chinese Field Dog (CFD) from a stress exposure group [including Beagle pituitary 1 (BP1), CFD pituitary 1 (CFDP1), Beagle adrenal cortex 1 (BAC1), CFD adrenal cortex 1 (CFDAC1)] and a control group [including Beagle pituitary 2 (BP2), CFD pituitary 2 (CFDP2), Beagle adrenal cortex 2 (BAC2), CFD adrenal cortex 2 (CFDAC2)], selected to perform RNA-seq transcriptome comparisons, showed that 40, 346, 376, 69, 70, 38, 57 and 71 differentially expressed genes were detected in BP1 vs. BP2, CFDP1 vs. CFDP2, BP1 vs. CFDP1, BP2 vs. CFDP2, BAC1 vs. BAC2, CFDAC1 vs. CFDAC2, BAC1 vs. CFDAC1 and BAC2 vs. CFDAC2 respectively. NPB was a gene common to BAC1 vs. BAC2 and CFDAC1 vs. CFDAC2, indicating it was a potential gene affecting response to chronic stress, regardless of the extent of chronic stress induced. PLP1 was a gene common to BP1 vs. CFDP1 and BP2 vs. CFDP2, suggesting its important roles in affecting the stress-tolerance difference between the two breeds, regardless of whether there was stress exposure or not. Pathway analysis found 12, 4, 11 and 1 enriched pathway in the comparisons of BP1 vs. CFDP1, BP2 vs. CFDP2, CFDP1 vs. CFDP2 and BAC1 vs. BAC2 respectively. Glutamatergic synapse, neuroactive ligand-receptor interaction, retrograde endocannabinoid signaling, GABAergic synapse, calcium signaling pathway and dopaminergic synapse were the most significantly enriched pathways in both CFDP1 vs. CFDP2 and BP1 vs. CFDP1. GO, KEGG pathway and gene network analysis demonstrated that GRIA3, GRIN2A, GRIN2B and NPY were important in regulating the stress response in CFD. Nevertheless, ADORA1, CAMK2A, GRM1, GRM7 and NR4A1 might be critical genes contributing to the stress-tolerance difference between CFD and Beagle when subjected to stress exposure. In addition, RGS4 and SYN1 might play important roles both in regulating the stress response in CFD and in affecting the stress-tolerance difference in different breeds. These observations clearly showed that some genes in the adrenal cortex and pituitary could regulate the stress response in Beagle and CFDs, whereas some others could affect the stress-tolerance difference between these two breeds. Our results can contribute to a more comprehensive understanding of the genetic mechanisms of response to chronic stress.

Identification of TDRP1 Gene and Its Association with Pig Reproduction Traits

This study was performed to identify and characterize the pig TDRP1 gene and to investigate its association with reproduction traits. The obtained pig TDRP1 cDNA (713 base pair [bp]) comprises a 561-bp open reading frame, which encodes a peptide of 187 amino acids. The identities of pig TDRP1 cDNA were 84.6%, 75.7%, and 77.4% with its counterparts in human, rat, and mice, respectively. Real-time polymerase chain reaction indicated that pig TDRP1 gene was highly expressed in pituitary of male and uterus of female animals. The pig TDRP1 gene contains three exons and two introns. A total of 13 single-nucleotide polymorphisms (SNPs) and 1 indel were identified in the screened partial genomic sequence, with most polymorphisms in introns. Allelic frequencies of five SNPs among eight pig breeds were further investigated, and it indicated that Landrace had the lowest genetic diversity. In Yorkshire, three SNPs (c.215+144T>C, c.215+249A>G, and c.215+672T>C) exhibited complete linkage disequilibrium in one haplotype block, and association analyses showed that all of them were significantly associated with number born alive of first parity (NBA1) (p<0.05). c.215+672T>C was also significantly associated with NBA6 (p<0.05). In addition, these three SNPs and two other ones (c.215+1001G>A and c.215+1026C>T) were associated with total born alive of second parity (TBA2) and TBA6 at the suggestive level (0.05

Identification and characterization of the pig ABIN-1 gene and investigation of its association with reproduction traits

1Department of Laboratory Animal Science, Medical College of Jinan University, Guangzhou, Guangdong 510632, People’s Republic of China 2Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou 510642, Guangdong, People’s Republic of China 3School of Bioscience and Bioengineering, South China University of Technology, Guangzhou 510006, People’s Republic of China 4Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, Guangzhou 510642, People’s Republic of China 5College of Life Sciences, Sichuan University, Chengdu, 610064, People’s Republic of China

Comparison of miRNA expression profiles in pituitary–adrenal axis between Beagle and Chinese Field dogs after chronic stress exposure

MicoRNAs (miRNAs), usually as gene regulators, participate in various biological processes, including stress responses. The hypothalamus–pituitary–adrenal axis (HPA axis) is an important pathway in regulating stress response. Although the mechanism that HPA axis regulates stress response has been basically revealed, the knowledge that miRNAs regulate stress response within HPA axis, still remains poor. The object of this study was to investigate the miRNAs in the pituitary and adrenal cortex that regulate chronic stress response with high-throughput sequencing. The pituitary and adrenal cortex of beagles and Chinese Field dogs (CFD) from a stress exposure group (including beagle pituitary 1 (BP1), CFD pituitary 1 (CFDP1), beagle adrenal cortex 1 (BAC1), CFD adrenal cortex 1 (CFDAC1)) and a control group (including beagle pituitary 2 (BP2), CFD pituitary 2 (CFDP2), beagle adrenal cortex 2 (BAC2), CFD adrenal cortex 2 (CFDAC2)), were selected for miRNA-seq comparisons. Comparisons, that were made in pituitary (including BP1 vs. BP2, CFDP1 vs. CFDP2, BP1 vs. CFDP1 and BP2 vs. CFDP2) and adrenal cortex (including BAC1 vs. BAC2, CFDAC1 vs. CFDAC2, BAC1 vs. CFDAC1 and BAC2 vs. CFDAC2), showed that a total of 39 and 18 common differentially expressed miRNAs (DE-miRNAs) (Total read counts > 1,000, Fold change > 2 & p-value < 0.001), that shared in at least two pituitary comparisons and at least two adrenal cortex comparisons, were detected separately. These identified DE-miRNAs were predicted for target genes, thus resulting in 3,959 and 4,010 target genes in pituitary and adrenal cortex, respectively. Further, 105 and 10 differentially expressed genes (DEGs) (Fold change > 2 & p-value < 0.05) from those target genes in pituitary and adrenal cortex were obtained separately, in combination with our previous corresponding transcriptome study. Meanwhile, in line with that miRNAs usually negatively regulated their target genes and the dual luciferase reporter assay, we finally identified cfa-miR-205 might play an important role by upregulating MMD in pituitary and hippocampus, thus enhancing the immune response, under chronic stress exposure. Our results shed light on the miRNA expression profiles in the pituitary and adrenal cortex with and without chronic stress exposure, and provide a new insight into miR-205 with its feasible role in regulating chronic stress in the pituitary and hippocampus through targeting MMD.