how does gene expression change over time do plant genes change why is it necessary to measure gene expression at different times of day what is the difference between genetic variation and environmental variation can i measure gene expression over time when each plant can be sampled a once why are plants only sampled once can a plant only be sampled once will fertilizer kill your plants how does gene expression change over time why do plants only get samples for each day how does gene expression change over time what is the difference between gene expression for different environments? how do we test gene expression in plants why do plants need to be sampled once how do we know if a plant will be killed why does plant gene expression change over time? why do we need to measure gene expression how do you measure gene expression on a cactus when can a plant be sampled only once?