Pedigrees & Pattern of Gene Inheritance

Target #19- I can describe the layout & purpose of a pedigree Many human disorders are genetic in origin  Genetic disorders are medical conditions caused by alleles inherited from the parents  Diagrammed in a pedigree  Pedigree: a chart of a family’s history with regard to a particular genetic trait Males are designated as squares Females are designated as circles A line between a square and a circle represents a mating A vertical line going downward leads to a child of the mating Child are listed in age from left to right Generations are identified with a roman numeral  Purpose of a pedigree is to follow the inheritance pattern of a particular trait Affect individuals are usually shaded

Target #20- I can identify the genotypes of a pedigree

Target #21- I can differentiate between autosomal recessive and autosomal dominant disorders Autosomal recessive disorders  Can be carried by the parents, and expressed by the child  Parents are heterozygous for disorder  Examples Cystic fibrosis Tay-Sachs Sickle-cell anemia Autosomal dominant disorders  Can be expressed by parents if they are heterozygous and not passed to the child  Examples Marfan Syndrome Huntington disease