Presentation is loading. Please wait.

Presentation is loading. Please wait.

The Chemosensory Recognition of Genetic Individuality Beauchamp, Yamazaki and Boyse.

Similar presentations

Presentation on theme: "The Chemosensory Recognition of Genetic Individuality Beauchamp, Yamazaki and Boyse."— Presentation transcript:

1 The Chemosensory Recognition of Genetic Individuality Beauchamp, Yamazaki and Boyse

2 Odor and Genes  The individual odor of an animal is in part determined by its genes  Genes in a chromosomal region in all mammals plays a major part in immunologic recognition  Largely decides the fate of transplanted organs and tissues  MHC = Major Histocompatibility Complex  Mice = H2  Dogs = DLA  Humans = HLA

3 Olfactory Recognition of Genetic Identity  H-2k and H-2d  k and d stand for the alleles  Alleles = alternative forms of these genes  Places in the genome where mutations occur with remarkable frequency  Two unrelated individual animals are extremely unlikely to have identical MHC types  Why it is difficult to find MHC-matched human organ donors and recipients, except within families  The proteins synthesized by cells of different individuals from instructions encoded by MHC genes are also diverse

4 Olfactory Recognition of Genetic Identity  Proteins products have carbohydrate chemical groups added = glycoproteins  Inserted into the outer membrane to form surface antigens

5 Mice Breeding  Inbred Strains  Derived by serial brother-to-sister matings over many generations  To the point of genetic uniformity  Congenic Strains  Derived by first crossing one inbred strain to another  Mate the progeny through many succeeding generations back to mice of the first inbred strain  Then select progeny in each backcross generation for a defined genetic difference  The result is two strains of mice that differ in only one segment of the genetic material  For MHC the congenic strains would be genetically identical except for the region of chromosome 17 that bears the MHC (H-2) group of genes

6 Congenic Mice ReceiverDonor

7 Filial Generations  The parental generation is the first set of parents crossed.  The F1 (first filial) generation consists of all the offspring from the parents - their children.  The F2 (second filial) generation consists of the offspring from allowing the F1 individuals to interbreed - the grandchildren of the parental generation.

8 F2 Linkage Test  A pair of H-2 congenic strains (genetically identical except for H-2) is crossed to produce the F1 generation  F1 – first filial (children)  The F1 population consists of genetically uniform mice that are H-2 heterozygotes  Every F1 mouse carries both the paternal and maternal H-2 alleles  The F1 H-2 heterozygotes are then crossed to give the F2 generation (grandchildren)  The F2 consists of two groups of H-2 homozygotes, each genetically identical with the respective inbred grandparent strain


10 Mating Preferences  Although the F2 homozygotes are genetically identical with the respective grandparents, they have experienced a different environment with respect to H-2  The H-2 mating preferences of F2 homozygotes were not in all cases identical with the preferences of genetically identical mice of the grandparental strains  The MHC-related mating preferences of mice are at least in part the result of familiar chemosensory imprinting

11 Basis of Mating Preferences  Mice can sense one another’s H2 types  Favoring partners that differ from themselves at the H2 locus  This bias favors outbreeding and H2 heterozygosity  Promotes diversity of H2 genes  May help the immune system adapt to new threats

12 Odor  It is well to remember that readily distinguishable compound odors can be generated simply by varying the proportions of the chemical constituents of a given mixture of odorants  Variations in the output of odorous metabolites arising from MHC genetic variation might alone account for individual odors related to MHC types

Download ppt "The Chemosensory Recognition of Genetic Individuality Beauchamp, Yamazaki and Boyse."

Similar presentations

Ads by Google