Lecture 19: Chromosomal Theory of Heredity

A review (along with self-test) can be found on the Cell biology page of the U of A biology project.

Walter Sutton (US grad student), Theodor Boveri (German Biologist) suggested that

Chromosomes contain the units of heredity

Sutton was motiviated by observations that sex seems to be determined by the presence/absence of a chromosome in the great lubber grasshopper (Brachystola magna)



Why? Because Mendel's particles parallel the behavior of chromosomes at meiosis

• Showed independent assortment of chromosomes using observations of a heteromorphic chromosome pair (from a grasshopper) at anaphase

Studies strains of Jimsonweed


Strains of containing different extra chromosomes different in fruit appearance. 12 stains containing different extra chromosomes and 12 different appearances.

• Used red and white-eyed mutants in Drosophila, see pg. 99- 102 (you will not be responsible for this reading, but it is interesting)
  

  X^R = red, X^r = white; Red dominant

  In females:

  X^R X^R , X^R X^r = red-eye female

  X^r X ^r = white-eyed females

  In males:

  X^R Y = red-eye male

  X^r Y = white-eyed male