Domestication differentially affects cochlear nucleus subdivisions in the gerbil

We analyzed the effects of domestication on the subdivisions of the cochlea r nucleus in the gerbil (Meriones unguiculatus) by comparing their volumes and rostrocaudal extents in laboratory gerbils and in age-matched Fl offspr ing of gerbils caught in the wild. In addition, soma size was systematicall y analyzed in the anteroventral cochlear nucleus of both groups. Total coch lear nucleus volume and rostrocaudal extent were not significantly differen t between groups either for young (postnatal day 9) animals before the onse t of hearing or for young 4-month-old animals. However, the dorsal cochlear nucleus was significantly larger and the anteroventral cochlear nucleus wa s significantly smaller in young adults of the wild strain. Thus the relati ve proportions of the cochlear nucleus subdivisions differed between the gr oups. In addition, soma size was significantly larger in the low-frequency portion of the anterovental cochlear nucleus in domesticated gerbils compar ed to wild gerbils. To our knowledge, this is the first reported instance o f a well-defined brain structure (e.g., the antreovental cochlear nucleus) being larger in the domesticated than in the wild form. J. Comp. Neurol. 42 8:609-615, 2000. (C) 2000 Wiley-Liss, Inc.