Dear All, using affy package latest release I noticed something odd with rma function. Performing statistical tests on expression levels I found few genes having exactly the same value, for example like these, 202117_at 10.124479 10.124479 10.124479 10.124479 10.124479 207451_at 5.539533 5.539533 5.539533 5.539533 5.539533 207481_at 4.135484 4.135484 4.135484 4.135484 4.135484 207494_s_at 7.522122 7.522122 7.522122 7.522122 7.522122 207576_x_at 5.764695 5.764695 5.764695 5.764695 5.764695 207588_at 3.613649 3.613649 3.613649 3.613649 3.613649 I was wondering what's the meaning of this result. If anybody have any experience on it I would thank some help. Bye Ale [[alternate HTML version deleted]]