Genetic heterogeneity

As heterogeneity is the phenomenon in genetics that the same feature ( phenotype) can be caused by different genes. Diseases that are caused heterogeneous, which can therefore go back to mutations in different genes are, for example albinism and hereditary deafness.

In heterogeneous diseases caused can, even if the disease-causing alleles are recessive, children of two ill parents be phenotypically healthy. If (A and B) disease-causing alleles (a and b ) occur for example when two genes, a concerned father with the genotype [ AAbb ] and also a concerned parent with the genotype [ aaBB ] can a healthy child with the genotype [ AABB ] testify.

Heterogeneity can significantly complicate the research on the causes of hereditary diseases, since it contributes in addition to the occurrence of different alleles and environmental factors to variations in the appearance of a disease.