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Plants Defy Mendel's Inheritance Laws, May Prompt Textbook Changes

Nature, 24 Mar. 2005

Contrary to inheritance laws that the scientific world has accepted for more than 100 years, some plants revert to normal traits carried by their grandparents, bypassing genetic abnormalities carried by both parents.

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Active Reading Questions

  1. Assume that two Arabidopsis plants are bred together. Both plants are homozygous for a mutant trait that makes the flowers fuse into a tight ball rather than opening as they should. What do you expect the offspring of these plants to look like?
    a) The offspring should have flowers fused into a tight ball like their parents.
    b) One fourth of the offspring should show the fused flowers, and three fourths of the offspring should have normal flowers.
    c) Three fourths of the offspring should show fused flowers, and one fourth of the offspring should have normal flowers.
    d) The offspring should have flowers that appear normal.
  2. Scientists did the cross as described in the question above, but found that some of the offspring had normal flowers rather than mutant flowers. How did the scientists explain this phenomenon?
    a) The scientists believe that there was accidental crossing with other experimental plants.
    b) The scientists believe that the plants are retaining the correct copy of the genetic information from the grandparent generation of plants.
    c) When homozygous recessive plants are bred, you get homozygous dominant offspring.
    d) One of the parents was actually heterozygous.
  3. The article refers to Mendel’s laws. Using your book, define Mendel’s two laws relating to inheritance.
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