Question

0 Required information To investigate the inheritance of color variegation in four-o'clocks, Carl Correns performed pairwise crosses between male (pollen) and female (ova) gametes from flowers growing on three types of branches: variegated, all white, and all green. Solid white branches are homoplasmic for mutant chloroplasts, solid green branches are homoplasmic for wild-type chloroplasts, and variegated branches are heteroplasmic for both types of chloroplasts. In a new species of variegated plant, color is determined by mutations in a chloroplast gene and chloroplasts are inherited from both parents. If all of the progeny from a cross are solid white, what can be concluded about the parent plants? Check All That Apply The ova could have come from a plant that was entirely white. The ova could have come from a branch that was solid white The ova could have come from a branch that was solid white or variegated, but not solid green

Answer 1

The solid green plants are homoplasmic and solid white are homoplasmic for the chloroplasts while variegated are heteroplasmic meaning they contain one allele from green and one from white. Hence if an offspring is solid white, then the ova can come from white plant or a variegated plant but not the green because it doesnt have any white allele and same goes for the pollen. Hence the correct options are:

The ova could have come from the branch that was solid white or variegated but not solid green
The pollen could have come from a plant that was entirely white
The pollen could have come from a branch that was solid white.
The pollen could have come from the branch that was solid white or variegated but not solid green

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