To do a DNA extraction and then start sequencing in the field.

我们要提取DNA，然后开始在农田里进行测序。”

So the first thing that we did was we had to do a DNA extraction.

所以我们做的第一件事就是必须进行 DNA 提取。

One of the biggest challenges in doing a DNA extraction is it usually requires very expensive equipment, and takes hours.

进行 DNA 提取的最大挑战之一是它通常需要非常昂贵的设备，并且需要数小时。