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1.
The major histocompatibility complex (MHC) of cattle is known as the bovine leukocyte antigen (BoLA) and is located on chromosome 23. BoLA has been linked to variation in resistance to disease including bovine leukemia virus‐induced lymphoma and mastitis. Moreover, BoLA appears to influence other traits such as milk yield, growth and reproduction, which are not often measured in humans, and variations in individual immune response to antigen. The BoLA appears to be organized in a similar way to the MHC region in humans, but there are notable differences. A major rearrangement within the class II region has led to the division of the BoLA into two distinct subregions of chromosome 23 separated by about a third of the chromosome’s length. The class IIa subregion contains functionally expressed DR and DQ genes, while the class IIb subregion contains the genes of undefined status such as DYA, DYB, DMA, DMB, DOB, DOA, TAP1, TAP2, LAP2 and LMP7. In addition, one pair of human class II genes (DP) does not appear to have an equivalent in cattle, and there is one pair of DY genes that seem to be found only cattle, sheep and goats. In humans, three classical, polymorphic class I genes (HLA‐A, ‐B and ‐C ) are each present on all haplotypes. However, in cattle, none of the four (or more) classical class‐I genes identified are consistently expressed, and haplotypes differ from one to another in both the gene number and composition. These variations in both class I and II are likely to play an important role in cattle immune responses. This review summarizes current knowledge of the structural and functional features and disease association of BoLA genes.  相似文献   

2.
The highly polymorphic genes within the major histocompatibility complex (MHC) not only play a major role in immunity resistance, but also seem to provide hints for mate choice in some animal populations. In the present study we investigated MHC‐related mate choice in a small natural population (group size 40–55 individuals) of a polygynous primate, the Sichuan snub‐nosed monkey (Rhinopithecus roxellana). We found that there was no evidence either for MHC‐disassortative mating, or for females to mate with males based on MHC heterozygosity or specific alleles. Nevertheless, of the 11 alleles identified, we found that the frequencies of 2 alleles, Rhro‐DRB2 (P < 0.01) and Rhro‐DRB5 (P < 0.05) were higher in offspring than in their parents. These findings suggest that MHC‐DRB in this population of R. roxellana is unlikely to be associated with mating preferences. Limited female opportunities for mate choice are likely due, in part, to the harem breeding structure present in R. roxellana, and the relatively small number of resident adult males in our study band (N = 4–6). In addition, we suggest that differences in the frequency of particular alleles across generations may be linked to parasite resistance in a fluctuating environment; however, confirmation of this finding requires further study.  相似文献   

3.
The major histocompatibility complex (MHC) is a gene complex closely linked to the vertebrate immune system due to its importance in antigen recognition and immune response to pathogens. To improve our understanding of the MHC and disease resistance in dairy cattle, we gathered 5119 test day records of somatic cell count (SCC) and performance traits of 262 Holstein dairy cows to determine whether the DRB region of the MHC contains alleles that are associated with elevated SCC, milk yield, protein and fat percent of milk. To this purpose, genotyping of animals for DRB3 gene was investigated by polymerase chain reaction‐based restriction fragment length polymorphism (PCR‐RFLP) assay. A two‐step PCR was carried out so as to amplify a 284 base‐pair fragment of exon 2 of the target gene. Second PCR products were treated with three restriction endonuclease enzymes RsaI, BstYI and HaeIII. Twenty‐eight BoLA‐DRB3 alleles were identified including one novel allele (*40). The results in general are in good accordance with allele frequencies of Holstein cattle populations reported by previous studies. Analyses of associations were modeled based on repeated measurement anova and generalized logistic linear methods for production traits and SCC data, respectively. The results of this study showed a significant relationship between the elevated SCC reflecting an increased probability of occurrence to subclinical mastitis and DRB3.2 allele *8 (p < 0.03). The results also revealed significant positive relationships of alleles*22 (p < 0.01) and allele*11 (p < 0.05) with milk fat percent as well as of alleles*24 (p < 0.03) and *22 (p < 0.05) with protein percent. The present study failed to find any association between milk yield and tested alleles. Because of the lack of consistency among results of similar studies, we suggest further investigations to determine the precise nature of these associations with the high polymorphic bovine MHC region to be performed based on haplotypes.  相似文献   

4.
The genetic variation at four milk protein loci αs1‐casein (CSN1S1), β‐casein (CSN2), κ‐casein (CSN3) and β‐lactoglobulin (LGB) was investigated in 358 animals belonging to seven populations well adapted to hot climatic conditions, reared in Africa and Italy. Bos taurus (Somba, Lagune and Modicana), Bos indicus (Sudanese Zebu Peul, Azaouak and Adamawa), and B. taurus × B. indicus (Borgou) were studied by adapting different molecular methodologies to evaluate their genetic variability. All loci were polymorphic and a new CSN2 synonymous variant, named A2′, was detected and characterized. Noteworthy differences in the distribution of alleles and haplotypes were observed between zebuine and taurine cattle showing that milk protein polymorphism is suited for discriminating B. taurus from B. indicus efficiently, and also taurine breeds. Milk protein loci, being positively selected loci, can also provide information about the occurrence of germplasm particularly useful for breeding strategies and production improvement.  相似文献   

5.
Liver‐expressed antimicrobial peptide 2 (LEAP‐2) is a cationic peptide that plays an important role in innate immunity for host defense. The aim of this study was to characterize the LEAP‐2 gene in the Japanese quail (Coturnix japonica). Japanese quail LEAP‐2 (CjLEAP‐2) was identified from the Japanese quail draft genome database by a local BLAST analysis using chicken LEAP‐2 (GgLEAP‐2). The exon‐intron structure of CjLEAP‐2, analyzed from three quails, is composed of three exons, as is the chicken LEAP‐2 homolog (GgLEAP‐2). An analysis of the coding sequence revealed that CjLEAP‐2 is 231 bp long, like GgLEAP‐2, and 93% identical to GgLEAP‐2 at the nucleic acid level. The predicted amino acid sequence of CjLEAP‐2 contained the liver‐expressed antimicrobial peptide 2‐precursor domain and four cysteine residues characteristic of the LEAP‐2 protein. The amino acid sequence of the mature peptide of CjLEAP‐2 was 100% identical to that of GgLEAP‐2. We confirmed that CjLEAP‐2 was transcribed in at least seven tissues, including the digestive system. Additionally, the mature peptide region of CjLEAP‐2 exhibited no polymorphisms in 99 quails from six strains. Taken together, these findings indicate that CjLEAP‐2 is non‐polymorphic and therefore, it likely plays an important role in the innate immunity of quail as it does in chicken.  相似文献   

6.
Major histocompatibility complex (MHC) class I genes encode highly polymorphic molecules that are expressed on virtually every cell type, and have been identified in all but the most primitive vertebrates. They play a number of crucial roles in the immune response to infectious disease. Most information regarding MHC genes has been generated from humans and mice but, because of the great variability found in the MHC system, it is not always possible to extrapolate from these to other species. Many strategies have evolved to maximise the ability of the MHC to protect individuals and populations against pathogens. Cattle MHC class I genes exhibit a number of unusual features. Evidence from mapping studies, haplotype and phylogenetic analyses suggests the presence of six classical class I loci, in contrast to the more usual two or three, and these are expressed in various combinations of one, two or three on different haplotypes. Although it remains difficult to assign alleles to loci, it appears that none of the loci are expressed on all haplotypes. There is currently limited information relating to polymorphism, but various approaches suggest diversity is high, and may vary between breeds/populations. Functional consequences of variable MHC haplotype composition are discussed. Identifying unique features of the MHC in cattle will lead to new insights into evolution of the immune system.  相似文献   

7.
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8.
Seoul National University (SNU) miniature pigs represent a closed colony with 24 founder pigs and a well preserved pedigree. Characterization using mRNA sequence analysis was conducted for 6 swine leukocyte antigen (SLA) loci in parental or founder pigs, and 17 defined alleles were detected. Based on these complete coding sequences, 17 sequence specific primers (SSPs) were designed for polymorphic sites. To validate the specificity of each allele SSP, the PCR‐SSP was conducted with defined allele clones as templates. PCR‐SSP was conducted with the hot start polymerase and touch‐down PCR. The parental or found SNU miniature pigs showed overall SLA class I and II heterozygotes. Using the established PCR‐SSP method, we conducted SLA typing for breeding stock including 2 pedigreed pigs and identified the novel SLA class II homozygote haplotye (DRA*0201, DRB1*0403, DQA*0102 and DQB1*0701) and 2 SLA homozygote pig lines: SLA class I Hp‐3.0 and class II Hp‐0.3, and SLA class I Hp‐2.0 and class II Hp‐0.2. We thought that our PCR‐SSP SLA typing method could be applicable for new SLA homozygote line establishment by assignment and scheduled breeding.  相似文献   

9.
Red‐crowned cranes (Grus japonensis) were classified as an endangered species by the International Union for Conservation of Nature, but recently, their population has decreased dramatically. For the purpose of conserving this endangered species, 18 microsatellite markers were developed, including 12 newly isolated ones from a genomic library and 6 modified from another crane species. The markers were characterized in 26 red‐crowned cranes. As a result, these markers displayed 3–13 alleles, and the observed and expected heterozygosities ranged from 0.462 to 1.000 and from 0.483 to 0.884, respectively. The marker suite averaged 6.390 alleles per locus with an average polymorphic information content of 0.631. The combined exclusion probability (PE‐1) was 0.9985, and the combined exclusion probability (PE‐2) was 0.9999. Three of the 18 microsatellite loci presented significant deviations from Hardy–Weinberg Equilibrium (P < 0.05), likely due to sampling bias and unknown founder relatedness in a semi‐free population. Our results show that microsatellite loci can provide a standard protocol for genetic information in red‐crowned crane populations upon which strategies for effective conservation and management may be based.  相似文献   

10.
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11.
选用鹌鹑上的12个微卫星位点,对随机选取朝鲜鹌鹑的40个个体进行多态性检测,共检测到55个等位基因,每个座位平均等位基因数为4.583个。该群体平均多态信息含量和平均杂合度分别为0.6945和0.7111,表明朝鲜鹌鹑属多态性较丰富的群体。  相似文献   

12.
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13.
Natural infections with influenza viruses have been reported in a variety of animal species including humans, pigs, horses, sea mammals, mustelids and birds. Occasionally, devastating pandemics occur in domestic chickens (broiler and layers) and in humans. From November 2003 to March 2004 in many countries in Asia, there were outbreaks of H5N1 avian influenza virus, causing death of infected patients, and devastating the poultry industry. Some groups of Thai indigenous chickens survived and were therefore classified as resistant. These traits were related to immunogenetics, in particular, the major histocompatibility complex (MHC) class I and class II molecules. The chicken MHC class I were investigated as candidate genes for avian influenza virus disease resistance. Seven hundred and thirty Thai indigenous chickens from smallholder farms in the rural area of avian influenza virus disease outbreaks in the central part of Thailand were used in the present study. They were separated into two groups, 340 surviving chickens and 390 dead chickens (resistant and susceptible). Genomic DNA were precipitated from blood samples and feathers. The DNA were used to amplify the MHC class I gene. Data were analyzed using χ2 analysis to test significant differences of influences of MHC class I haplotypes on avian influenza virus disease traits. The results represented nine MHC class I haplotypes: A1, B12, B13, B15, B19, B21, B2, B6, and BA12, and included 10 of their heterozygotes. The homozygous B21 from these collected samples had a 100% survival rate and they were the major survival group. In addition, the heterozygous B21 also had a high survival rate because of co‐dominant expression of these genes. In contrast, the homozygous B13 had a 100% mortality rate and they were the major mortality group. These results confirmed that MHC class I haplotypes influence avian influenza virus disease‐resistant traits in Thai indigenous chicken. The MHC genes can be used as genetic markers to improve disease‐resistant traits in chicken.  相似文献   

14.
Up to 173 African sires belonging to 11 different subpopulations representative of four cattle groups were analysed for six Y‐specific microsatellite loci and a mitochondrial DNA fragment. Differences in Y‐chromosome and mtDNA haplotype structuring were assessed. In addition, the effect of such structuring on contributions to total genetic diversity was assessed. Thirty‐five Y‐chromosome and 71 mtDNA haplotypes were identified. Most Y‐chromosomes analysed (73.4%) were of zebu origin (11 haplotypes). Twenty‐two Y‐haplotypes (44 samples) belonged to the African taurine subfamily Y2a. All mtDNA haplotypes belonged to the “African” taurine T1 haplogroup with 16 samples and nine haplotypes belonging to a recently identified subhaplogroup (T1e). Median‐joining networks showed that Y‐chromosome phylogenies were highly reticulated with clear separation between zebu and taurine clusters. Mitochondrial haplotypes showed a clear star‐like shape with small number of mutations separating haplotypes. Mitochondrial‐based FST‐statistics computed between cattle groups tended to be statistically non‐significant (p > .05). Most FST values computed among groups and subpopulations using Y‐chromosome markers were statistically significant. AMOVA confirmed that divergence between cattle groups was only significant for Y‐chromosome markers (ΦCT = 0.209). At the mitochondrial level, African sires resembled an undifferentiated population with individuals explaining 94.3% of the total variance. Whatever the markers considered, the highest contributions to total Nei's gene diversity and allelic richness were found in West African cattle. Genetic structuring had no effect on patterns of contributions to diversity.  相似文献   

15.
We carried out a genetic association study between five nucleotide polymorphisms (5′UTR microsatellite ((TG)n), nt‐7(C>A), L24V, DelR242 and Intron 1 microsatellite) of the GHSR1a gene and growth and carcass traits in 1285 steers sired by 117 Japanese Black bulls in a progeny testing program. We report herein, a significant association between the 5′UTR microsatellite and nt‐7(C>A) loci and growth and carcass traits. We also propose a translational hypothesis that the association is due to differences in the secondary structure of GHSR1b mRNA (the non‐spliced type with the 5′UTR microsatellite) among the GHSR1a gene haplotypes. Furthermore, we predicted the potential increase in profitability due to increased carcass weight in cow‐calf fattening enterprises through planned matings based on DNA testing of the 5′UTR microsatellite. Statistical analysis revealed that the 5′UTR microsatellite locus had a significant additive effect on carcass weight (CW) and average daily gain (ADG), but not on beef marbling score (BMS). One of the four major microsatellite alleles (19‐TG allele) with an allele frequency of 0.145, had a significantly (P < 0.0007) desirable effect on CW and ADG. We concluded that the 19‐TG allele could potentially be economically useful nucleotide markers for growth and carcass traits in Japanese Black cattle.  相似文献   

16.
1. The importance of MHC genes and background genes in controlling disease resistance, including resistance to avian coccidiosis, has not been clarified in meat‐type chickens.

2. The role of class IV MHC genes in resistance to Eimeria acervulina was assessed in F2 progeny of a cross between 2 meat‐type lines, selected divergently for immune response to Escherichia coli.

3. Disease susceptibility was assessed by lesion score, body weight, packed cell volume and carotene absorption.

4. Chickens with the “K” class IV MHC haplotype had lower lesion scores than chickens with “F” and “A” haplotypes.

5. Plasma carotene concentrations were higher in chickens with “K” haplotype and lower in chickens with “F” and “A” haplotypes whereas body weight and packed cell volume were less sensitive measures of Eimeria infection.

6. Eimeria acervulina resistance appears to be associated with MHC class IV genes; information about MHC haplotypes may be useful in selecting for increased resistance of meat‐type chickens to coccidiosis.  相似文献   


17.
Chickens and Japanese quail (Coturnix japonica) have traditionally been the primary avian models in developmental biology research. Recently, the blue‐breasted quail (Coturnix chinesis), the smallest species in the order Galliformes, has been proposed as an excellent candidate model in avian developmental studies owing to its precocious and prolific properties. However, data on the embryonic development of blue‐breasted quail are scarce. Here, we developed a normal developmental series for the blue‐breasted quail based on developmental features. The blue‐breasted quail embryos take 17 days to reach the hatching period at 37.7°C. We documented specific periods of incubation in which significant development occurred, and created a 39‐stage developmental series. The developmental series for the blue‐breasted quail was almost identical to that for chickens and Japanese quail in the earlier stages of development (stages 1–16). Our staging series is especially useful at later stages of development (stages 34–39) of blue‐breasted quail embryos as a major criterion of staging in this phase of development was the weight of embryos and the length of third toes.  相似文献   

18.
本研究以33头广西巴马小型猪为研究对象,利用19个微卫星标记,通过估算其等位基因数(N)、多态信息含量(PIC )和近交系数(F)等参数,对广西巴马小型猪近交群F10~F15世代进行了遗传学检测。试验结果显示,19个微卫星座位上共检测到31个等位基因,其中F10~F15分别具有27、29、28、27、26和25个等位基因,平均每个位点分别仅有1.42、1.53、1.47、1.42、1.37和1.32个等位基因;6个世代群体平均多态信息含量为0.1044。广西巴马小型猪F10~F15世代的平均近交系数分别为0.8070、0.8263、0.8491、0.8710、0.8904、0.9118。结果表明,广西巴马小型猪近交群体的基因多态性低、近交程度高,是一个遗传性稳定的群体。  相似文献   

19.
Comparative genomics of the poultry major histocompatibility complex   总被引：5，自引：0，他引：5  
This review summarizes the latest findings regarding the avian major histocompatibility complex (MHC), focusing particularly on the genomics of MHC in the Japanese quail (Cotrnix japonica) and other birds, as well as haplotype, genomics, function and disease resistance in the chicken (Gallus gallus). This information provides important insight into the breeding of disease resistance in poultry, natural selection of disease resistance in wild birds, and the effects of recombination and hitchhiking on the evolution of multiple MHC gene families.  相似文献   

20.
We present here the first genome‐wide characterization of linkage disequilibrium (LD) in the French Blonde d'Aquitaine (BLA) breed, a well‐muscled breed renowned for producing high‐yielding beef carcasses. To assess the pattern and extent of LD, we used a sample of 30 unrelated bulls and 36 923 single nucleotide polymorphisms (SNPs) covering all cattle autosomes. The squared correlation of the alleles at two loci (r2) was used as a measure of LD. The analysis of adjacent marker pairs revealed that the level of LD decreases rapidly with physical distance between SNPs. Overall mean r2 was 0.205 (±0.262). Strong LD (r2 > 0.8) and useful LD (measured as r2 > 0.2) were observed within genomic regions of up to 720 and 724 kb, respectively. We analysed the genetic structure of the BLA population and found stratification. The observed genetic sub‐structuring is consistent with the known recent demographic history that occurred during BLA breed formation. Our results indicate that LD mapping of phenotypic traits in the BLA population is feasible; however, because of this sub‐structuring, special care is needed to reduce the likelihood of false‐positive associations between marker loci and traits of interest.  相似文献   

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