Inheritance

*Enduring understanding 3.A: Heritable information provides for continuity of life.

-Essential knowledge 3.A.3: The chromosomal basis of inheritance provides an understanding of the pattern of passage (transmission) of genes from parent to offspring.

• a. Rules of probability can be applied to analyze passage of single gene traits from parent to offspring. b. Segregation and independent assortment of chromosomes result in genetic variation. Evidence of student learning is a demonstrated understanding of each of the following:
  • 1. Segregation and independent assortment can be applied to genes that are on different chromosomes.
  • 2. Genes that are adjacent and close to each other on the same chromosome tend to move as a unit; the probability that they will segregate as a unit is a function of the distance between them.
  • 3. The pattern of inheritance (monohybrid, dihybrid, sex-linked, and genes linked on the same homologous chromosome) can often be predicted from data that gives the parent genotype/phenotype and/or the offspring phenotypes/genotypes.
• c. Certain human genetic disorders can be attributed to the inheritance of single gene traits or specific chromosomal changes, such as nondisjunction.
• d. Many ethical, social and medical issues surround human genetic disorders.
  • Learning Objectives:
    • LO 3.12 The student is able to construct a representation that connects the process of meiosis to the passage of traits from parent to offspring. [See SP 1.1, 7.2]
    • LO 3.13 The student is able to pose questions about ethical, social or medical issues surrounding human genetic disorders. [See SP 3.1]
    • LO 3.14 The student is able to apply mathematical routines to determine Mendelian patterns of inheritance provided by data sets. [See SP 2.2]

-Essential knowledge 3.A.4: The inheritance pattern of many traits cannot be explained by simple Mendelian genetics.

• a. Many traits are the product of multiple genes and/or physiological processes. Evidence of student learning is a demonstrated understanding of the following:
  • 1. Patterns of inheritance of many traits do not follow ratios predicted by Mendel’s laws and can be identified by quantitative analysis, where observed phenotypic ratios statistically differ from the predicted ratios.
• b. Some traits are determined by genes on sex chromosomes
• c. Some traits result from nonnuclear inheritance. Evidence of student learning is a demonstrated understanding of each of the following:
  • 1. Chloroplasts and mitochondria are randomly assorted to gametes and daughter cells; thus, traits determined by chloroplast and mitochondrial DNA do not follow simple Mendelian rules.
  • 2. In animals, mitochondrial DNA is transmitted by the egg and not by sperm; as such, mitochondrial-determined traits are maternally inherited.
    • Learning Objectives:
      • LO 3.15 The student is able to explain deviations from Mendel’s model of the inheritance of traits. [See SP 6.5]
      • LO 3.16 The student is able to explain how the inheritance patterns of many traits cannot be accounted for by Mendelian genetics. [See SP 6.3]
      • LO 3.17 The student is able to describe representations of an appropriate example of inheritance patterns that cannot be explained by Mendel’s model of the inheritance of traits. [See SP 1.2]