scholarly journals GENETIC DIVERSITY OF THE MAJOR HISTOCOMPATIBILITY COMPLEX BY USING LEI0258 MICROSATELLITE MARKER ASSOCIATED WITH PRODUCTIVE PERFORMANCE AND VIRAL DISEASES IN BROILER BREEDERS

2021 ◽  
Vol 41 (2) ◽  
pp. 279-297
Author(s):  
Farid Nassar
Keyword(s):  
Genetic Diversity ◽  
Major Histocompatibility Complex ◽  
Microsatellite Marker ◽  
Viral Diseases ◽  
Productive Performance ◽  
Major Histocompatibility ◽  
Broiler Breeders ◽  
Histocompatibility Complex

Genetic diversity at the Major Histocompatibility Complex class II DZB gene, and geographical distribution of alleles, in platypuses in a Tasmanian river catchment.

2019 ◽  
Vol 40 (2) ◽  
pp. 241-250
Author(s):  
J.W. Macgregor ◽  
C. Holyoake ◽  
S. Munks ◽  
J.H. Connolly ◽  
I.D. Robertson ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Major Histocompatibility Complex ◽  
Mhc Class Ii ◽  
Class Ii ◽  
Major Histocompatibility ◽  
Island Populations ◽  
Low Genetic Diversity ◽  
Histocompatibility Complex ◽  
Wildlife Populations ◽  
River Catchments

Genetic diversity at loci concerned with fitness is an important part of the ability of a wild population to adapt to changes in its environment, including climatic events, disease and pollution. Research into the effects of genetic diversity on the impacts of disease on wildlife populations has focussed on genes of the major histocompatibility complex (MHC). This study investigated the genetic diversity at the MHC class II DZB gene, as well as the distribution of alleles of the same gene, for platypuses Ornithorhynchus anatinus in the Seabrook Creek Catchment in northwest Tasmania. This study detected 10 previously identified alleles and two previously unreported alleles at the MHC Class II DZB locus in 18 platypuses from the Seabrook Creek Catchment. An additional sequence isolated from two individuals was consistent with a pseudogene. Alleles were reasonably well distributed geographically through the catchment, but there was evidence of a degree of isolation at one site. Consistent with evidence that smaller wildlife populations have relatively low genetic diversity, and that there is relatively slow gene flow between river catchments, the observed genetic diversity at the MHC Class II locus was lower than those in larger previously studied river catchments but higher than those in two island populations. Consequently, this population of platypuses may have a limited capacity to respond to new infectious challenges, such as the fungal disease mucormycosis.

scholarly journals Polymorphism in the major histocompatibility complex (MHC class II B) genes of the Rufous-backed Bunting (Emberiza jankowskii)

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e2917 ◽  
Author(s):  
Dan Li ◽  
Keping Sun ◽  
Yunjiao Zhao ◽  
Aiqing Lin ◽  
Shi Li ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Major Histocompatibility Complex ◽  
Mhc Class Ii ◽  
Nucleotide Diversity ◽  
Environmental Changes ◽  
Major Histocompatibility ◽  
High Genetic Diversity ◽  
Exon 2 ◽  
Histocompatibility Complex ◽  
Segregating Sites

Genetic diversity is one of the pillars of conservation biology research. High genetic diversity and abundant genetic variation in an organism may be suggestive of capacity to adapt to various environmental changes. The major histocompatibility complex (MHC) is known to be highly polymorphic and plays an important role in immune function. It is also considered an ideal model system to investigate genetic diversity in wildlife populations. The Rufous-backed Bunting (Emberiza jankowskii) is an endangered species that has experienced a sharp decline in both population and habitat size. Many historically significant populations are no longer present in previously populated regions, with only three breeding populations present in Inner Mongolia (i.e., the Aolunhua, Gahaitu and Lubei557 populations). Efforts focused on facilitating the conservation of the Rufous-backed Bunting (Emberiza jankowskii) are becoming increasingly important. However, the genetic diversity ofE. jankowskiihas not been investigated. In the present study, polymorphism in exon 2 of the MHCIIB ofE. jankowskiiwas investigated. This polymorphism was subsequently compared with a related species, the Meadow Bunting (Emberiza cioides). A total of 1.59 alleles/individual were detected inE. jankowskiiand 1.73 alleles/individual were identified inE.cioides. The maximum number of alleles per individual from the threeE. jankowskiipopulations suggest the existence of at least three functional loci, while the maximum number of alleles per individual from the threeE. cioidespopulations suggest the presence of at least four functional loci. Two of the alleles were shared between theE. jankowskiiandE. cioides. Among the 12 unique alleles identified inE. jankowskii, 10.17 segregating sites per allele were detected, and the nucleotide diversity was 0.1865. Among the 17 unique alleles identified inE. cioides, eight segregating sites per allele were detected, and the nucleotide diversity was 0.1667. Overall, compared to other passerine birds, a relatively low level of MHC polymorphism was revealed inE. jankowskii, which was similar to that inE. cioides. Positive selection was detected by PAML/SLAC/FEL analyses in the region encoding the peptide-binding region in both species, and no recombination was detected. Phylogenetic analysis showed that the alleles fromE. jankowskiiandE. cioidesbelong to the same clade and the two species shared similar alleles, suggesting the occurrence of a trans-species polymorphism between the twoEmberizaspecies.

scholarly journals Genetic diversity, evolution and selection in the major histocompatibility complex DRB and DQB loci in the family Equidae

BMC Genomics ◽  
2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Marie Klumplerova ◽  
Petra Splichalova ◽  
Jan Oppelt ◽  
Jan Futas ◽  
Aneta Kohutova ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Major Histocompatibility Complex ◽  
Positive Selection ◽  
Mhc Class Ii ◽  
Class Ii ◽  
Major Histocompatibility ◽  
Histocompatibility Complex ◽  
Depth Analysis ◽  
The Family ◽  
Antigen Presenting

Abstract Background The mammalian Major Histocompatibility Complex (MHC) is a genetic region containing highly polymorphic genes with immunological functions. MHC class I and class II genes encode antigen-presenting molecules expressed on the cell surface. The MHC class II sub-region contains genes expressed in antigen presenting cells. The antigen binding site is encoded by the second exon of genes encoding antigen presenting molecules. The exon 2 sequences of these MHC genes have evolved under the selective pressure of pathogens. Interspecific differences can be observed in the class II sub-region. The family Equidae includes a variety of domesticated, and free-ranging species inhabiting a range of habitats exposed to different pathogens and represents a model for studying this important part of the immunogenome. While equine MHC class II DRA and DQA loci have received attention, the genetic diversity and effects of selection on DRB and DQB loci have been largely overlooked. This study aimed to provide the first in-depth analysis of the MHC class II DRB and DQB loci in the Equidae family. Results Three DRB and two DQB genes were identified in the genomes of all equids. The genes DRB2, DRB3 and DQB3 showed high sequence conservation, while polymorphisms were more frequent at DRB1 and DQB1 across all species analyzed. DQB2 was not found in the genome of the Asiatic asses Equus hemionus kulan and E. h. onager. The bioinformatic analysis of non-zero-coverage-bases of DRB and DQB genes in 14 equine individual genomes revealed differences among individual genes. Evidence for recombination was found for DRB1, DRB2, DQB1 and DQB2 genes. Trans-species allele sharing was identified in all genes except DRB1. Site-specific selection analysis predicted genes evolving under positive selection both at DRB and DQB loci. No selected amino acid sites were identified in DQB3. Conclusions The organization of the MHC class II sub-region of equids is similar across all species of the family. Genomic sequences, along with phylogenetic trees suggesting effects of selection as well as trans-species polymorphism support the contention that pathogen-driven positive selection has shaped the MHC class II DRB/DQB sub-regions in the Equidae.

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