Sections of mouse embryos from E11 to E15 were labelled with probes derived from the common EGF-like region of the GGF gene.

This conclusion was supported by experimental observations in our laboratories indicating that probes derived from rat and mouse cDNAs yield inconsistent results in Northern blotting under stringent hybridization conditions (data not shown).

Our main results are the scatterplot showing microarray hybridization signals using a probe derived from muscle mRNA, versus the signals using only an oligo(dT) probe (Fig.

Let the signal obtained at spot number i from hybridization with the probe derived from muscle mRNA be denoted as H i .

For each of these genes, probes derived from the 5', middle and 3' portions of the genes are arrayed.

To circumvent these problems, we used techniques that allow us to carry out several hybridizations with probes derived from different tissues of a single animal.

The locations of repeated sequences within the heterochromatin have been studied using in situ hybridization of probes derived from known repeated elements to mitotic chromosomes [ 26, 27].

These oligos are then hybridized with labeled probe derived from a given tissue or cell line.

By using a probe derived from an NKG2 C clone, we identified a number of transcripts by Northern blot analysis (Fig.

Lane 1 contains free probe while lane 8 contains probe derived from the plasmid pBEND2 by BamHI digestion.