Effects of temperature, dissolved oxygen, current velocity, and byssogenesis status on gene expression in the zebra mussel foot using cDNA microarray analysis. The figure displays the different treatment combination selected as per the loop design approach. Each arrow represents one microarray hybridization. The start of the arrow stands for the sample labelled with dye Alexa 647 while the end point of an arrow represents the sample labelled with dye Alexa 555. L stands for low temperature (4°C) while R stands for a higher temperature (22°C); S stands for static water while F means flow water stirred by magnetic stirring bars; H represents the low dissolved oxygen level (5 mg/L) while the N represents the normal dissolved oxygen level (10 mg/L); A and D stand for attachment and detachment status, respectively.