Hi All, I have a idiots doubt! I have a data files with R and G intensities. The layout in the slides is: 1 2 3 . . . 23 3 1 4 3 1 4 3 1 4 A 2 X 3 2 X 3 2 X 3 1 4 2 1 4 2 1 4 2 3 1 4 3 1 4 3 1 4 B 2 X 3 2 X 3 2 X 3 1 4 2 1 4 2 1 4 2 . . . N The data file is: Row Col Grid Dup label Gf Gb CV Rf Rb DV A 1 3 1 A-1:3 198 74 124 47 29 18 A 1 1 1 A-1:1 180 69 111 31 29 1 A 1 4 1 A-1:4 63 55 7 30 29 1 A 1 2 1 A-1:2 73 68 6 29 29 0 A 1 3 2 A-1:3 151 63 89 41 28 13 A 1 1 2 A-1:1 89 62 28 31 28 3 A 1 4 2 A-1:4 72 66 6 31 30 1 A 1 2 2 A-1:2 66 58 9 34 27 7 A 1 B B A-1:B 61 65 0 28 28 0 A 2 3 1 A-2:3 122 56 65 34 30 3 A 2 1 1 A-2:1 74 57 17 30 28 2 A 2 4 1 A-2:4 74 57 17 29 28 1 A 2 2 1 A-2:2 275 61 214 43 30 13 A 2 3 2 A-2:3 109 64 45 33 31 2 A 2 1 2 A-2:1 102 62 40 31 28 3 A 2 4 2 A-2:4 93 62 31 31 28 3 A 2 2 2 A-2:2 347 62 284 34 30 4 A 2 B B A-2:B 60 62 0 30 30 0 B=blank I have ngrid.r=3, ngrid.c=3, nspot.r=14, nspot.c=23, ndups=2, spacing=4, start="topleft". limma will duplicate spot each four spacing. But, when it found a "B", what it to do? Because blank spot dont have dup. How do I do to solve this problem? Or it dont have solution. Thanks in advanced. -- Marcelo Luiz de Laia, M.Sc. Dep. de Tecnologia, Lab. Bioqu?mica e de Biologia Molecular Universidade Estadual Paulista - UNESP Via de Acesso Prof. Paulo Donato Castelane, Km 05 14.884-900 - Jaboticabal, SP, Brazil PhoneFax: 16 3209-2675/2676/2677 R. 202/208/203 (trab.) HomePhone: 16 3203 2328 - www.lbm.fcav.unesp.br - mlaia@yahoo.com