Heterosis for brain myelin content in mice.

Biochemical evidence of heterosis (hybrid vigor) for brain myelin content is presented. The concentrations of cerebroside and GM1 ganglioside, two glycolipids known to be abundant in myelin, were higher in the brains of (C57BL/6J X DBA/2J) F1 hybrids than in the brains of either parental strain. Furthermore, brain water content, which is known to be inversely related to myelin content, was lower in the F1 hybrids, especially during the most active period of myelin synthesis. Heterosis was not observed, however, for total brain ganglioside concentration. Additionally, the results do not substantiate a direct developmental-genetic relationship between brain myelin content and susceptibility to audiogenic seizures.