just scientific factors but also the practical aspects, such as how likely it is that funding can be secured for sequencing a genome.

FINDING THE BALANCE BETWEEN SCIENTIFIC INTEREST AND PRACTICAL NEEDS

One of the most important things in identifying which genomes to sequence, O’Brien said, is to maintain a balance between the purely scientific interest in various genomes and the practical benefits that can be gained from sequencing them. “If we’re going to get the resources for sequencing, we cannot be so academic and ideal as to ignore the fact that it is taxpayers or pharmaceutical companies who will have to write tens of millions of dollars in checks. We need to have benefits that will pay them back for their investment. So there’s always going to have to be a balance between scientific relevance and things that have a payoff in other ways.”

Medical Relevance

In terms of funding potential, the most important practical criterion is medical relevance, O’Brien noted, since that is what the NIH is most interested in, and it is the NIH that to date has been the major source of funds for genome sequencing. To appeal to the NIH, researchers interested in sequencing the genomes of domestic animals will have to consider which work will address issues of human health.

“The most important aspect, then,” O’Brien said, “is what can we do with a species?” O’Brien noted how the mouse, for example, was selected in part for its versatility for genetic manipulation. Scientists can develop lines or families of mice by inducing mutations by “knocking out” genes (Knockouts are the deactivation of specific genes, and are often created in laboratory organisms such as yeast or mice so that scientists can study the knockout organism as a model for a particular disease). They also can be used to develop stem cells to be delivered for medical research. Due to their small size and fast generation time, mice are easy to breed and sustain in captivity and are inexpensive to maintain in laboratories (compared to other mammals). These features allow researchers to derive inbred lines for studies of genetic disorders. Mice also are used for drug and vaccine trials. More recently, researchers have been able to develop transgenic versions for even more research and investigation.

“Which of those things can we say about cattle?” asked O’Brien. Which of those things can we say about the elephant? Which of those things can we say about the other species we nominate?”

“In these terms, the pig genome is a natural choice for sequencing because growth and development in the pig follows a very similar path to



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