I wrote back, basically saying we were sequencing the genome but alas our data might not be useful for his question since most of what we were doing at the time was predicting gene splice sites not actually determining them for real. And I said, in fact, much of the data in Genbank was also predictions not real cDNAs.
I expected him to be a bit disappointed. But instead, he wrote back to Peter:
Peter:What I was struck with was his sense of humor and warmth, which emanated from this and a few other simple email messages. Based on these communications, I was looking forward to interacting with him again as we are now writing up a paper including all of our new cDNA data (real sequences, not predictions). I am sorry to see him go.
Thank you! Jonathan's response confirms that I was right to ask an expert. For if I had gone fishing in the gene bank pool, I should probably have drowned. I shall wait, calmly.