Heterosis for brain myelin content in mice

Biochemical evidence of heterosis (hybrid vigor) for brain myelin content is presented. The concentrations of cerebroside and G_M1 ganglioside, two glycolipids known to be abundant in myelin, were higher in the brains of (C57BL/6J × 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.