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Building a better mouse -- rodent, that is
Analysis/Humor
Scientists at Emory University announced this week that they
successfully transferred a
sequence of genes from a species of rodent called a vole (field mouse)
to that of an average
mouse. The effect was astounding. The resulting mouse displayed
affiliation, pair-bonding, and
paternal care, like the monogamous vole, and so unlike the antisocial
lab rodent.
Of course, this writer promptly fired off an email asking the spokeswoman at Emory to identify the
animal sociologist on staff. But, like other pointed questions untimely
asked, his query found no
takers, and he was tempted to go out and purchase the August issue of
Nature magazine to
fathom the secret.
The gist of an answer, however, lies in the core of Emory's
press release. The animal under study represents a new species
of "transgenic" creature, an animal derived from the genes of
two separate species. The process involves inserting a snippet
of DNA from one animal into the genome of another. Since genes
are chains of chemical bonds, a new chain can be inserted within
the existing chain, resulting in a longer, more complex, chain
with the attributes of both. In the case of the mouse, the
inserted chain gave instructions to produce receptors for
the chemical vasoprossin which, distributed and "turned on"
in the new animal's brain, compelled the social behavior sought.
From polygamous and antisocial, the transgenic mice went
on to be monogamous and gregarious. (This also goes to show
that the best laid plans of mice and men sometimes work out happily.)
Perhaps the most interesting part of the experiment
involved the layering of causal factors. One, mice and
vole have been observed to be different and suspected
to respond differently to the chemical vasopressin,
produced in their brains. Two, DNA from the vole was
inserted into the nucleus of mouse eggs, leading to
physically vole-like mice. Three, in the presence of
vasopressin, the activity of mice, as evidenced by
their responses to environmental factors like the company
of females and kin, showed vole-like traits.
Doubtless, the originally polygamous mice now enjoy life a bit less,
miss living on the edge, and pine for the Faustian thrill of breaking the rules --
but they probably earn more and can afford plush vacations and better
furniture. The research was funded by the National Institute of
Mental Health, which supports a continuing plot to
tinker with the genome of mice.
August 28, 1999
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