Human Traits

 I. Pedigrees  Pedigrees are a graphic representation of human inheritance.

  Traits that are inherited by having 2 recessive alleles.  Ex: Cystic Fibrosis- a disease that results in the formation and accumulation of thick mucus in the lungs and digestive tract.  (A video on Cystic Fibrosis) II. Simple Recessive Heredity

 C = normalCC & Cc = normal c = cystic fibrosiscc = CF Example of Inheritance: Cc x Cc GR: 1CC: 2Cc: 1cc PR: 3 normal : 1 cystic fibrosis Cystic Fibrosis Cc CCCCc c cc

  Tay Sach’s Disease- A recessive disorder of the central nervous system. Children born with this die at an early age due to lack of an enzyme that breaks down lipids that then accumulate in cells. (Tay Sach’s Video) More Simple Recessive Inheritance

  Phenylketonuria- a recessive disease that does not allow people to convert a specific amino acid properly, causing mental retardation. Can be treated by avoiding phenylalanine in the diet. (PhenylketonuriaVideo) More Simple Recessive Inheritance

  Traits that are inherited by having just one dominant allele.  Ex: Huntington’s Disease: a lethal genetic disorder that effects the neurological function of a person, generally between the ages of  (Video on Huntington’s Disease) II. Simple Dominant Heredity

 h = normalHH & Hh= Huntington’s H = Huntington’shh = normal Example of Inheritance: Hh x Hh GR: 1HH: 2Hh: 1hh PR: 3 Huntington’s : 1 normal Huntington’s Disease Hh HHHHh h hh