Molecular Genetics

Proteins, such as the histocompatibility antigens, can serve as molecular markers for the genetic chromosome.

Facts

• When tissue is transplanted from one strain (A) of mouse to a genetically related strain (B), the tissue survives.
• However, when the tissue is transplanted to a different strain (C), the tissue is rejected.
• Two closely linked loci, part of the major histocompatibility complex of genes, are primarily responsible for the tissue compatibility or incompatibility.
• The loci code for cell surface proteins involved in cell-cell interactions and the presentation of antigens to the immune system.
• The loci are highly polymorphic.

Interpretations

• Because of the involvement of histocompatibility antigens in antigen presentation, some alleles of these loci are associated with resistance or susceptibility to particular diseases.
• Proteins can serve as molecular markers for the genetic chromosome.
• Highly polymorphic loci, such as those for the histocompatibility antigens, should be useful to the study of the genetics of populations.
• Such highly polymorphic loci can be used in forensics to establish identity of individuals or tissues.

Further information

• Proteins can also serve as molecular markers through their enzymatic activities.
• The mouse MHC region contains the H2 major histocompatibility loci.
• The human major histocompatibility antigens are the HLA proteins.