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| Modern Genetic Analysis Chapter 4. The Inheritance of Genes Inheritance of Organelle Genes Figure 4-30. Leaf variegation in Mirabilis jalapa, the four-o'clock plant. (a) Flowers may form on any branch (varie-gated, green, or white), and these flowers may be used in crosses. (b) In crosses between flowers on different-colored branches, color of the zygote and resulting plant is deter-mined by maternal inheritance. The first two crosses shown here exhibit strict maternal inheritance. If the maternal branch is variegated, three types of zygotes can result, depending on whether the egg cell contains only white, only green, or both green and white chloroplasts. Maternal inheritance still applies in all three types, but in the variegated zygotes, a process of cytoplasmic segregation during subsequent cell divisions produces a mosaic of all-green and all-white cells, hence, a variegated plant.

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