Speaking of Cats

I enjoyed the editorial on cat domestication (C&EN, July 16, page 3). As the primary author on the original paper, I find it a relief that my several years of work garnered attention outside of my immediate colleagues.

I must, however, take exception to one small point. While it's true that I have a burning desire for doing science, I'm compelled to suggest several practical uses, both conservation- and human-health-related, for the research I did, as well as implications for more basic science into evolution and human cultural development.

Like mice, rats, or rabbits, cats are used as "model" organisms in research on human diseases. Cats are one of the best models we have for the study of virally mediated cancers such as feline leukemia virus (Felv). They are also used as models for many human genetic diseases (two that we study here are polycystic kidney disease and retinal atrophy), so the more we know about cats, the more accurate they will be as models.

What my study showed is that domestic cats throughout the world are related through a common ancestor. This means that, roughly, all cats are the same. This is important and comforting because it means that a researcher in the U.S., say, and China or the U.K. can compare their results without worrying about the confounding influence of different genetic backgrounds of their study organisms.

Conservation is the second practical benefit of this work. Because domestication is such a recent event—not just for cats but for all domesticates—the domestic derivatives and their wild ancestors are still capable of breeding together. This "intercrossing" breaks up adaptive gene complexes found in the wild and compromises the wild taxon's survival. The particular problem with cats is that domestication changed cats little morphologically but did so manifestly in terms of behavior.

The lack of morphological differentiation makes domestics and wildcats difficult if not impossible to distinguish in many cases, making conservation difficult. With this paper, I present several genetic markers useful in segregating the two that can be used to establish areas free of domestics where wildcats can breed without competition or intercrossing.

The remaining benefits are the least tangible. This is the first phylogeny of this species to have been done, and it shows us how this relatively young species has changed over the past 300,000 years. Beyond being intrinsically interesting, this result may help develop cats into a model of evolutionary research.

Furthermore, because cats themselves seem to have initiated domestication at a time and place when humans were becoming sedentary, cats are indicative of a human cultural adolescence when we were transitioning from hunting and gathering to agriculturally driven urbanization. This is interesting not just for its own sake, but it is also helpful in coloring in the outlines of our own species' maturation.

Carlos Driscoll
Frederick, Md.