. Plant breeders studying genes influencing leaf shape in the plant Arabidopsis
thaliana identified six independent recessive mutations that resulted in plants that
had unusual leaves with serrated rather than smooth edges. The investigators started
to perform complementation tests with these mutants, but some of the tests could
not be completed because of an accident in the greenhouse. The results of the
complementation tests that could be finished are shown in the table that follows.
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1-+-+
2
3
4
5
9
+
a. Exactly what experiment was done to fill in individual boxes in the table with a
plus (+) or a minus (-)? What does + represent? What does represent? Why
are some boxes in the table filled in green?
b. Assuming no complications, what do you expect for the results of the
complementation tests that were not performed? That is, complete the table by
placing a + or a - in each of the blank boxes.
How many genes are represented among this collection of mutants? Which