Morgan's criticism of Stevens' and Wilson's sex determination theory.
Stevens' and Wilson's sex determination work: who was first to make the discovery?
A description of the "Chromosome debate" that took place during Morgan's time.
Summary of the Chromosome "theory" pre-Morgan.
How & why Drosophila became the experimental model of choice in Morgan's laboratory.
Thomas Hunt Morgan's talent as a laboratory group leader.
Morgan's three "star" students: Sturtevant, Bridges, and Muller.
Human chromosome number and the "notion" of chromosomes.
The genesis of the idea of crossing over.
The experimental evidence for crossing over.