Genetics and inheritance

• Recessive inheritance

  -the trait skips a generation

  -two parents with the trait must have offspring who also have the trait
• Dominant inheritance

  -the trait doesn’t skip a generation

  -two affected parents can have a non-affected child —>parents heterozygous.
• Autosomal inheritance

  -Equal numbers of males and females are affected.

  -two unaffected parents can have both sons and daughters with the trait.
• X-linked inheritance

  -more males affected than females

  -affected females will pass on trait to all sons —> if trait is recessive

  -affected males will only pass on allele to daughters —> sons only receive Y chromosome from their fathers.

  -two unaffected people can only have an affected son.
• Heterozygous -> hybrid 


  The inheritance of different alleles (Aa)
• Homozygous -> purebred 


  The inheritance of two of the same allele (AA, aa)
• What is genetic counseling?

  A form of advise where they examine the incidence of a disorder is a family tree, the probability that a particular condition will occur can sometimes be determined.