Inheritance and Pedigree Charts

Co-Dominance
1. both alleles are dominant and expressed equally in the phenotype
2. Example - ABO blood grouping, both alleles A and B are Dominant and so are co-dominant,allele O is recessive
Incomplete Dominance
1. One allele is dominant but not completely.
2. the other allele will show in the phenotype, but not to the same extent.
3. Example - Sickle Cell Anemia, HH (normal), HsHs (sickle-cell anemia), HHs (sickle cell trait - 30%)
Sex - Linkage
1. Genes attached to X chromosome are sex linked genes as Y chromosome carries almost no genes.
2. Conditions will likely show in the phenotype of males
3. Examples - Red/Green colour blindness, Haemophilia, Muscular Dystrophy.
Pedigree Charts
1. Autosomal Dominant Inheritance.
  1. *Parents who are unaffected have unaffected children. * the characteristic is seen in every generation. *Both sexes are equally affected.
2. Autosomal Recessive Inheritance
  1. *Parents who are both heterozygous can have affected children. *Children of affected parents always inherit the recessive allele. *both sexes are equally affected. * can skip generations
3. Sex - linked Inheritance
  1. *Many more males then females are affected. *only female can be carriers. *can skip generations.

Resource summary

	Created by Emma.h.watt over 9 years ago