Biomaterial Database

Dynamics of Mhc evolution in birds and crocodilians: amplification of class II genes with degenerate primers. 1995

S V Edwards, and M Grahn, and W K Potts

Center for Mammalian Genetics, University of Florida, Gainesville 32610, USA.

Genes of the major histocompatibility complex (Mhc) are the most polymorphic functional loci in mammalian populations, but little is known of Mhc variability in natural populations of nonmammalian vertebrates. To help extend such studies to birds and relatives, we present a pair of degenerate primers that amplify polymorphic segments of one chain (the beta chain) of the class II genes from the major histocompatibility complex (Mhc) of archosaurs (birds+crocodilians). The primers target two conserved regions lying within portions of the antigen-binding site (ABS) encoded by the second exon and amplify multiple genes from both genomic DNA and cDNA. The pattern of nucleotide substitution in ABS codons of 51 sequences amplified and cloned from five species of passerine birds and an alligator (Alligator mississippiensis) indicates that archosaurian class II beta genes are subject to selective forces similar to those operating in mammalian populations. Hybridization of a genomic clone generated by the primers revealed highly polymorphic bands in a sample of Florida scrub jays (Aphelocoma coerulescens coerulescens). Because the primers amplify only part of the ABS from multiple class II genes, they will be useful primarily for generating species specific clones, thereby providing a critical inroad to more detailed structural and evolutionary studies.

UI	MeSH Term	Description	Entries
D008285	Major Histocompatibility Complex	The genetic region which contains the loci of genes which determine the structure of the serologically defined (SD) and lymphocyte-defined (LD) TRANSPLANTATION ANTIGENS, genes which control the structure of the IMMUNE RESPONSE-ASSOCIATED ANTIGENS, HUMAN; the IMMUNE RESPONSE GENES which control the ability of an animal to respond immunologically to antigenic stimuli, and genes which determine the structure and/or level of the first four components of complement.	Histocompatibility Complex,Complex, Histocompatibility,Complex, Major Histocompatibility,Complices, Histocompatibility,Complices, Major Histocompatibility,Histocompatibility Complex, Major,Histocompatibility Complices,Histocompatibility Complices, Major,Major Histocompatibility Complices
D008969	Molecular Sequence Data	Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.	Sequence Data, Molecular,Molecular Sequencing Data,Data, Molecular Sequence,Data, Molecular Sequencing,Sequencing Data, Molecular
D003001	Cloning, Molecular	The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.	Molecular Cloning
D005075	Biological Evolution	The process of cumulative change over successive generations through which organisms acquire their distinguishing morphological and physiological characteristics.	Evolution, Biological
D005784	Gene Amplification	A selective increase in the number of copies of a gene coding for a specific protein without a proportional increase in other genes. It occurs naturally via the excision of a copy of the repeating sequence from the chromosome and its extrachromosomal replication in a plasmid, or via the production of an RNA transcript of the entire repeating sequence of ribosomal RNA followed by the reverse transcription of the molecule to produce an additional copy of the original DNA sequence. Laboratory techniques have been introduced for inducing disproportional replication by unequal crossing over, uptake of DNA from lysed cells, or generation of extrachromosomal sequences from rolling circle replication.	Amplification, Gene
D005802	Genes, MHC Class II	Genetic loci in the vertebrate major histocompatibility complex that encode polymorphic products which control the immune response to specific antigens. The genes are found in the HLA-D region in humans and include H-2M, I-A, and I-E loci in mice.	Class II Genes,Genes, Class II,Genes, HLA Class II,MHC Class II Genes,Class II Gene,Gene, Class II
D000489	Alligators and Crocodiles	Large, long-tailed reptiles, including caimans, of the order Loricata.	Caimans,Crocodiles,Alligators,Caymans,Alligator,Caiman,Cayman,Crocodile,Crocodiles and Alligators
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001483	Base Sequence	The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.	DNA Sequence,Nucleotide Sequence,RNA Sequence,DNA Sequences,Base Sequences,Nucleotide Sequences,RNA Sequences,Sequence, Base,Sequence, DNA,Sequence, Nucleotide,Sequence, RNA,Sequences, Base,Sequences, DNA,Sequences, Nucleotide,Sequences, RNA
D001717	Birds	Warm-blooded VERTEBRATES possessing FEATHERS and belonging to the class Aves.	Aves,Bird