We started the… the story talking about the… our interest in polymorphisms and how they relate to disease susceptibility, and that was the initiation of the research and it's kind of characterized the research, our research, on hepatitis and I think those of others as well, and there's… there's a lot of… a kind of message from… from this approach that I think is very important now at… at a time when so much is… progress is being made in genomics and proteomics. A consequence of this view of things is that, you know, a gene, in a sense, never operates, or nearly never operates, on its own. There are some genes that are highly deterministic and although there's… if you have the gene, the probability of getting an associated phenomena, an associated disease is… is extremely high. But those… there are many of those but they tend to be rare, and the total sum they contribute to the disease load of humans is relatively small compared to things like heart disease, stroke, you know, diabetes, infections; they're a small part of the load. Now, the genetics that's involved with these really big diseases that kill a lot of people and the ones that most people are concerned about, they tend to be these sort of susceptibility genes which means they're not highly deterministic and that their interactions with other genes in the same environment, with environmental factors and with behavior, is extremely important and you have to understand the whole complex. So the bottom line is biology isn't destiny and you can change the effects of your genes and that's what doctors do all the time; you know, if you have diabetes and your insulin's not being processed properly, or you're not producing enough of it, they give you insulin. That's interfering with the effects of the genes. If you're… if you have genes that make you susceptible… susceptible to hepatitis B virus and we've identified, we and others, have identified multiple loci, well, you get the vaccine and you don't get hepatitis. So the effect of the genes is… is inconsequential there.

Now, the other interesting thing is that the very same genes that make you susceptible to hepatitis B virus also make you susceptible to specific other organisms and we developed a… a approach to that, in which we developed a classification of infectious agents based on the fact that each of the agents in this particular category, this… the classification, are related to the same susceptibility gene. Now, in some… in some cases, a allele that makes you susceptible to one of those agents will make you resistant to another, so you can't talk about good genes and bad genes. You have to talk about a good in what way, or bad in what way, and… and as a consequence, by the way, this notion of gene substitution therapy, the idea you get a bad gene, you get it out and put… or… or change its impact, and then put a big gene in, another gene, quotation marks, ‘good gene’, I think it's not… it's not going to work and it hasn't worked, you know, there's no substitutional gene therapy, because it goes ahead on the notion that the main function of the gene, which is usually the first one that's found, is the only function. Well, it's patent… you know, genes have multiple functions. Now, part of the reasons that they have multiple functions is that nature doesn't throw genes away. Nature tends to conserve them, and, you know,  that's very… that can be studied quantitatively by looking at the conservation parts of the gene or different genes and they come to us from… from species, you know, that are earlier on the evolutionary scale than humans, and I think one of the most amazing biological findings of the past century was that mammals share a third of their genes with archaea. Now, archaea are… are, it's thought, the… one of the organisms, a group of organisms, bacteria-like organisms that differ in their gene sequences and a variety of other ways from bacteria, that they are… they're very early in the scale of living matter and they may conceivably have been the first living things. And then there, by the way, there are viruses in archaea and I'll get to that later when we talk about space. So we share genes. Well, those genes still have… still contain the potential of the organisms from which they came, and in a way we… it's very hard to know what those are because they were expressed in very different environmental situations. Well, nobody knows… can foretell the future; we're actually… we are foretelling the future now we're considering climate change and it's going to, you know, which independent… well, climate change with human cause attached to it. Well how are we going to respond to that new environment? And one of my current interests, or a major current interest, is how earth-bound organisms respond to being in space. And as I said, I'll get to that later, but I… but I did want to make this point that we continue… we never gave up our interest in this inherited susceptibility to disease and… and the work on hepatitis really — subsequent work — really made that patently clear.