Chapter 2, Problem 11P

Some inbred strains of the weedy plant Arabidopsis thaliana flower early in the growing season, but other strains flower at later times. Four different Arabdiposis plants (1–4) were crossed, and the resulting progeny were tabulated as follows:

Mating	Progeny
1×2	77 late : 81 early
1×3	134 late
1×4	93 late : 32 early
2×3	111 late
2×4	65 late : 61 early
3×4	126 late

a.	Explain the genetic basis for the difference in flowering time. How do you know that among this group of plants, the flowering time trait is influenced by the action of a single gene? Which allele is dominant and which recessive?
b.	Ascribe genotypes to the four plants.
c.	What kinds of progeny would you expect if you allowed plants 1–4 to self-fertilize, and in what ratios?