Biology S1002E (Summer 2002)
Notes for Week #4
Roger B. Blumberg

Wednesday, June 19th

• We'll begin with questions about Homework Set #1, which is due by Friday at noon.

• We continue reading Mendel's paper, rationally reconstructing his experiments and analyzing his findings. Here are a couple of questions to think about beforehand:
  • For each trait, what is the minimum number of phenotypic forms required to account for Mendel's findings? what is the minimum number of genotypic forms required?
  • What is the purpose of the Mendel's studying the multi-trait crosses in the latter sections of the paper?
  • What is the purpose of back-crossing a phenotypically dominant plant with a recessive?
  • Mendel's "laws" are sometimes described in textbooks as "The Law of Random Segregation" and "The Law of Independent Assortment". Where do we find the formulation or justification of either/each in Mendel's paper?

• For Next Time: Find an experiment in Mendel's paper in which all the reported data falls within 1 standard deviation of the mean.
• For Next Time2: Report on some aspect of the study of natural history or biology that changed considerably between 1865 and 1900.

Thursday, June 20th

• We'll finish our discussion of Mendel, and ask whether and to what extent Mendel's findings could hold for other traits in peas, and in plants and animals generally.

• Can Mendel's findings be given a clear interpretation in light of early 20th century studies of cells and chromosomes?

• What are some obvious next experimental questions to ask after Mendel? What questions could be answered by looking at cells? What questions could be answered only by looking at entire organisms?

• For Next Time: Read Morgan 1910 and Sturtevant 1913