Abundance categories of the common genes in human and baboon CD34⁺ cells.

A total of 15 407 cDNAs whose expression varies less than 3-fold between human and baboon CD34⁺ RNAs were arbitrarily grouped into 4 relative expression categories, from low to very high abundance. The categories, based on the signal intensity of the human RNA relative to filter background, are as follows: no expression (< 3-fold), low abundance (3-fold to < 10-fold), intermediate (10-fold to < 25-fold), high 25-fold to < 100-fold), and very high abundance (100-fold and higher).