Gorilla RH-like genes and antigens

Area of Science:

• Genetics and Molecular Biology
• Immunology
• Primate Blood Group Systems

Background:

• Human IgG monoclonal D-specific antibodies identify a gorilla polymorphism (Dgor-positive/negative).
• Previous studies established the existence of Dgor antigen on gorilla red blood cells (RBCs).

Purpose of the Study:

• To characterize the Dgor antigen expression and its genetic basis in gorillas.
• To compare the genetic mechanisms of Dgor polymorphism with human RhD system.

Main Methods:

• Quantitative indirect immunofluorescence assay and quantitative immunoblotting to assess Dgor antigenic site density.
• Immunoblotting with an anti-Rh polypeptide reagent to identify Rh-like polypeptides.
• Southern blot analysis using a human RHCE probe and polymerase chain reaction (PCR) to investigate genetic variations (intron length, polymorphic bands).

Main Results:

• Dgor antigenic site density on gorilla RBCs varies significantly, comparable to or higher than human RhD-positive cells.
• All gorillas possess 33,000 relative molecular mass Rh-like polypeptides.
• Dgor expression correlates with specific polymorphic bands (Southern blot, RHCE probe) and intron 3 length polymorphism (PCR), but not with intron 4 length polymorphism (Alu-Sx element).

Conclusions:

• Gorilla genome contains at least two RH-like genes; one is responsible for the observed Dgor polymorphism.
• The genetic basis of Dgor polymorphism in gorillas shows parallels with human RhD system, particularly regarding intron 4.
• Phylogenetic analysis of human and gorilla RH genes, based on intron 4 sequences, provides insights into their evolutionary relationship.