DNA polymorphism in the major histocompatibility complex of man and various farm animals.
Abstract: In the past few years it has been possible by combining enzymatic cleavage of genomic DNA and the Southern blot hybridization technique to explore the endonuclease recognition site polymorphism of the MHC. HLA class I and DR and DQ alpha and beta class II specific probes as well as human C4 and Bf class III probes were used. All these probes were shown to cross-hybridize with DNA from pigs, cattle, sheep and horses. Hybridization of human genomic DNA with a class I probe showed 15-25 bands per genome depending on the enzyme used. Distinct endonucleases generated clusters of restriction fragments (RF) in HLA-informative families which correlated with HLA specificities. While numerous clusters were found associated with HLA-A alleles almost no cluster was related to HLA B or C specificities. Similarly, class II probes provided a large number of clusters. The existence of these clusters suggested that some polymorphic restriction sites are found in strong linkage disequilibrium and that the underlying mechanism might be gene conversion with heteroduplex correction. Since the degree of polymorphism detected by RF appears to be greater than the polymorphism defined by more traditional methods stronger associations between RF and pathological conditions are to be expected. Southern blot analysis was applied to unrelated pigs and sheep, as well as to families. Preliminary studies have also been performed on a few unrelated cattle and horses. Depending on the endonuclease used the HLA class I probe hybridized with around 15 bands in MHC heterozygous pigs and ruminants while up to 20 bands were found in horses. Therefore, a several-fold greater number of potential class I genes exist compared to those actually expressed. With the class II beta probe, cattle and sheep showed around 10 bands whereas 15 were observed in pigs and around 20 in horses. Based on limited results obtained with DQ alpha and beta probes and with the DR alpha probe there appeared to be fewer of these respective genes. Only one C4 gene has been detected in pig and this gene maps within the SLA region. Hybridization with the human C4 probe in cattle, sheep and horses revealed two to four bands which could possibly account for two C4 genes. To date their linkage to the MHC has not been established. The Southern blot hybridization technique represents a powerful tool for future immunogenetic studies.(ABSTRACT TRUNCATED AT 400 WORDS)
Publication Date: 1986-01-01 PubMed ID: 2426996DOI: 10.1111/j.1365-2052.1986.tb00732.xGoogle Scholar: Lookup
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- Comparative Study
- Journal Article
Summary
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The research explores the genetic diversity present in the major histocompatibility complex (MHC) of humans and certain farm animals. Employing a combination of genomic DNA enzymatic cleavage and the Southern blot hybridization technique, the researchers unearth a higher degree of polymorphism than previously identified using traditional methods.
Understanding the Major Histocompatibility Complex (MHC)
- The MHC is a set of genes that plays a vital role in the immune system. The genes are responsible for manufacturing proteins that help the immune system recognize and respond to foreign substances.
- In this paper, the researchers analyze the DNA polymorphism in the MHC of humans and various farm animals including pigs, cattle, sheep, and horses. DNA polymorphism refers to the differences in the DNA sequence among individuals.
Techniques and Procedures
- The researchers used a combination of enzymatic cleavage of genomic DNA and the Southern blot hybridization technique to investigate the endonuclease recognition site polymorphism of the MHC. This process involves the fragmentation of DNA and subsequent analysis of those fragments to identify genetic variations.
- The team applied various human class I, II, and III specific probes, all of which were shown to cross-hybridize with DNA from the farm animals studied. This indicates the presence of similar genetic sequences across these species.
- They used several endonucleases, which are enzymes that cut DNA at specific recognition sites, resulting in distinct clusters of restriction fragments (RF), correlating with HLA (human leukocyte antigen) specificities. The HLA is the human version of the MHC.
Findings and Implications
- The researchers discovered that the degree of polymorphism identified through RF analysis was greater than the polymorphism defined by more traditional methods. This suggests that some polymorphic restriction sites exist in strong linkage disequilibrium, possibly due to gene conversion with heteroduplex correction.
- They also applied the Southern blot analysis to unrelated pigs, sheep, and families. Some preliminary studies were performed on a few unrelated cattle and horses.
- A major finding is that a significantly larger number of potential class I genes exist compared to those actually expressed. Class II genes exhibited a similar pattern.
- Ultimately, their findings underscore that the Southern blot hybridization technique represents a valuable tool for future immunogenetic studies in humans and certain species of farm animals.
Conclusion
The researchers in this study effectively illustrate how the Southern blot hybridization technique offers an enhanced understanding of the genetic diversity present within the MHC of humans and certain farm animals. The detection of higher degrees of polymorphism suggests future research could find stronger associations between RF analysis results and pathological conditions.
Cite This Article
APA
Vaiman M, Chardon P, Cohen D.
(1986).
DNA polymorphism in the major histocompatibility complex of man and various farm animals.
Anim Genet, 17(2), 113-133.
https://doi.org/10.1111/j.1365-2052.1986.tb00732.x Publication
Researcher Affiliations
MeSH Terms
- Animals
- Animals, Domestic
- Cattle
- DNA / metabolism
- DNA Restriction Enzymes
- Epitopes / analysis
- Genes
- Genetic Linkage
- H-2 Antigens / genetics
- Horses
- Humans
- Major Histocompatibility Complex
- Mice
- Nucleic Acid Hybridization
- Polymorphism, Genetic
- Sheep
- Species Specificity
- Swine
Citations
This article has been cited 4 times.- Bergmann T, Moore C, Sidney J, Miller D, Tallmadge R, Harman RM, Oseroff C, Wriston A, Shabanowitz J, Hunt DF, Osterrieder N, Peters B, Antczak DF, Sette A. The common equine class I molecule Eqca-1*00101 (ELA-A3.1) is characterized by narrow peptide binding and T cell epitope repertoires. Immunogenetics 2015 Nov;67(11-12):675-89.
- Tallmadge RL, Lear TL, Antczak DF. Genomic characterization of MHC class I genes of the horse. Immunogenetics 2005 Nov;57(10):763-74.
- Ansari HA, Hediger R, Fries R, Stranzinger G. Chromosomal localization of the major histocompatibility complex of the horse (ELA) by in situ hybridization. Immunogenetics 1988;28(5):362-4.
- Nesse LL, Paulsen G, Syed M, Ruff G. A human major histocompatibility complex (MHC) DNA probe recognizes goat genes. Acta Vet Scand 1988;29(2):193-8.
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