be controlled by a semi-dominant gene

例句：

1. 1. The disease iscontrolled by a semi-dominant gene that makes it hardto spread.
   这种疾病是由一种半支配基因控制的，很难传播。
2. 2. The scientist believes thatthe virus is controlled by a semi-dominant gene.
   科学家认为这种病毒是由一种半支配基因控制的。
3. 3. The researcher discovered that the bacteria was controlled bya semi-dominant gene.
   研究人员发现这种细菌是由一种半支配基因控制的。