Putting It Together: History of Life

The illustration shows a Dalbergia sissoo plant, which is short with pods and teardrop-shaped leaves.

Figure 1. Dalbergia sissoo

At the start of this module, we stated that if a plant contains a compound that is effective in treating disease, scientists might want to examine all of the relatives of that plant for other useful drugs. Let’s take a look at one example of this.

Dalbergia sissoo (D. sissoo) is in the Fabaceae, or legume family. A research team in China identified a segment of DNA that was thought to be common to some medicinal plants in the family Fabaceae (Figure 1). They then worked to identify which species had this segment. After testing plant species in this family, the team found a DNA marker (a known location on a chromosome that enabled them to identify the species) present.

Then, using the DNA to uncover phylogenetic relationships, the team could identify whether a newly discovered plant was in this family and assess its potential medicinal properties.

Subsequently, scientists found that D. sissoo  and other species with this DNA marker did, in fact, share fungicidal activity, supporting the idea that DNA markers can be used to screen for plants with potential medicinal properties.


It is tempting to view different topics as completely separate, but in fact the ideas we cover in this course are often connected to one another. If you don’t retain the vocabulary from module to module, those connections can be missed. As you continue on, remember to come back and review the terms you’ve learned in order to increase your depth of knowledge.