BIO 111: FOUNDATIONS OF BIOLOGY

LECTURE 11: "Mendelian Heredity"

Assumed Knowledge:

none

Study Questions for Chapter 14:

• List Mendel's four postulates, clearly and specifically stating his 'first principle' of heredity.
• Why is a test cross an effective way of determining the genotype of an individual?
• Determine the genotypic and phenotypic ratios from the following crosses. Assume dominance of capital letter:

      a.  AA x AA

      b.  AA  x Aa

      c.  Aa  x  Aa

      d.  Aa x  aa

      e.  aa x aa

• Why did Mendel conduct reciprocal crosses?
• Why did Mendel conduct an F1 x F1 cross (the second generation of crosses)?
• How did the results from the reciprocal crosses suggest that both parents must contribute genetic information?
• What question was Mendel aswering with his dihybrid cross?
• How did the results lead him to hypothesize that the traits must be inherited independently?
• State Mendel's second principle.
• Consider this cross:     (male) AaBbCcDD   x    (female) AaBBccDD

      -   Assume independent assortment and dominance (capital is dominant to lower case) at each gene.

      - How many types of gametes can each parent make with respect to these traits?

      - How many genotypes and phenotypes are possible in the progeny?

      - What fraction of offspring would you expect to express the ABCD phenotype?