Give an account of genetic control of Rh factor ?

Explanation

Fisher and Race hypothesis : Rh factor involves three different pairs of alleles located on three located on three different closely linked loci on the chromosome pair . This system ismore commonly in use today , and uses the ,Cde . nomenclature .
In the given figure , three pairs of Rh alleles (Cc , Dd and Ee) occur at 3 different loci on homologous chromosome parir - 1 . The possible genotypes will be one C or c , one D or d, one E or e from each chroomosome . For e.g CDE/cde , CdE/cDe , cde/cde ,CDe/CdE etc . All genotypes carrying a dominant .D. allele will produce `Rh^(+)` positive phenotype and double recessive genotype .dd. will give rise to Rh negative phenotype .
Wiener Hypothesis
Wiener proposed the existance of eight alleles `(R^(1),R^(2),R^(0),R^(z),r,r^(1),r^(11),r^(y))` at a single Rh locus . All genotypes carrying a dominant .R allele . `(R^(1),R^(2),R^(0),R^(z))` will produce .Rh - positive . phenotype and double recessive genetypes` (rr,rr^(1),rr^(11),rr^(y))` will give rise to Rh - negative phenotype .