blood_mn: The MN blood system
In coda.base: A Basic Set of Functions for Compositional Data Analysis

blood_mn

R Documentation

The MN blood system

Description

In humans the main blood group systems are the ABO system, the Rh system and the MN system. The MN blood system is a system of blood antigens also related to proteins of the red blood cell plasma membrane. The inheritance pattern of the MN blood system is autosomal with codominance, a type of lack of dominance in which the heterozygous manifests a phenotype totally distinct from the homozygous. The possible phenotypical forms are three blood types: type M blood, type N blood and type MN blood. The frequencies of M, N and MN blood types vary widely depending on the ethnic population. However, the Hardy-Weinberg principle states that allele and genotype frequencies in a population will remain constant from generation to generation in the absence of other evolutionary influences. This implies that, in the long run, it holds that

\frac{x_{MM}x_{NN}}{x_{MN}} = \frac{1}{4}

where xM M and xN N are the genotype relative frequencies of MM and NN homozygotes, respectively, and xM N is the genotype relative frequency of MN heterozygotes. This principle was named after G.H. Hardy and W. Weinberg demonstrated it mathematically.