Thursday, April 30, 2009

A novel strain of kat-transgenic mice that make nothing

Magdalena Fonseca and Jesús Cansado
Instituto Federal del Trabajo, Puebla, Mexico

Chronic laziness is one of the major burdens at modern society, with harmful consequences for industry (absenteeism), academy (school failure), and home (dishing quarrels) environments. Here, we have studied the molecular basis of chronic laziness using castrated, well-fed domestic cats as a paradigm of passive organisms in the Animal Kingdom. Comparative genomics on domestic cats which had been suffered preventive castration, versus those from wildlife-relatives, including American puma and Iberian lynx, revealed the presence on domestic cats of an unique set of genes, arranged in tandem, which were named as kat (kinetic-absent tandem) genes. The number of kat genes fluctuated from a few of them to several dozens, depending on the animals, indicating frequent gene duplications and/or deletions during adaptation of the cats to their particular home niche. In addition, kat genes shared the feature of being highly repetitive and with an extremely boring nucleotide sequence. To assess the physiological function of the kat genes products, transgenic mice strains were engineered that integrated in their genomes several copies of kat genes. Sets of kat genes (kit-kats) were cloned in integrative vectors under the control of the rodent yawn promoter, and microinjected in mice embryos. No particular morphological or pathological phenotype was observed on the kat-transgenic mice, which gained weight steadily after birth and looked quite healthy, with the exception of an exacerbated mating unwillingness in the male transgenic animals, even when highly receptive non-transgenic females were around. In line with this apparent lack of sexual appetite, the kat-transgenic mice displayed a fancifully penetrant behavioural phenotype, which essentially consisted in the mice making nothing, all day and night long. These results demonstrate that kat genes are responsible for passive behaviour and inactivity in domestic cats. Our preliminary investigations reveal the presence of active kat-like genes in humans that watch TV serials on a regular basis. We propose the kat-transgenic mice here described as a suitable animal model to test new non-alcoholic drugs against human chronic laziness and acute boredom.

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