AP Biology/Heredity

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Introduces how traits are passed down from one generation to the next.[1]

Objectives and Skills[edit | edit source]

Topics may include:[2]

  • The process and function of meiosis
  • The concepts genetic diversity
  • Mendel’s laws and probability
  • Non-mendelian Inheritance
  • Factors affecting inheritance and gene expression

Pedigree[edit | edit source]

  • Dominant - One of the parents must have the trait; every affected child of non-affected parents has one affected parent.
  • Recessive - Neither parents are required to have it as they're heterozygous; the male parent is affected, but there is an offspring with parents that are not affected; if any affected individual has 2 parents to which they're not affected, then it's recessive.
  • Autosomal - Both males and females are equally liked; parents aren't affected. Son or daughter is affected; affected son with an affected parent.
  • Sex-linked - Males are more affected.
  • X-linked - Carrier's female.
  • Polygenic traits - Traits controlled by multiple genes instead of just one gene.
  • Recombinant phenotypes - Combinations of traits that are different from either parent. Crossing over causes this.
  • Non-disjunction - Failure of the chromatids of the homologous chromosomes/sister chromatids to separate.
  • Polyploidy - A condition in which the cells of an organism have more than two paired (homologous) sets of chromosomes.
  • Trisomic - Down Syndrome
  • Monosomic - Turner's Syndrome
Alteration of chromosome structure
  • Deletion - Removes a chromosomal segment.
  • Duplication - Repeats a segment.
  • Inversion - Reverses a segment within a chromosome.
  • Translocation - Moves a segment from 1 chromosome to another, non-homologous one.
Inheritance from Dad

Deletion of a particular segment of chromosome 15 causes...

  • Prader-Willi Syndrome - Intellectual disability, catatonia, excessive weight gain, and small hands and feet.
  • Angelman syndrome - Uncontrollable laughter and jerk movements.

See Also[edit | edit source]

References[edit | edit source]