Introduction

Phylogenetic trees are important tools for understanding the evolutionary history of species. One method for creating these trees is the Unweighted Pair Group Method with Arithmetic Mean (UPGMA) algorithm. In this article, we will discuss how to create a UPGMA tree for five plants.

Step 1: Collect Data

The first step in creating a UPGMA tree is to collect data on the plants you are interested in analyzing. This can include physical characteristics such as leaf shape and size, flower color, or genetic information such as DNA sequences.

Step 2: Measure Similarities between Plants

Once you have collected your data, you need to determine the similarities between each pair of plants. This can be done using various methods such as comparing physical characteristics or analyzing genetic sequences.

Step 3: Create a Matrix

Next, you will need to create a matrix that lists the similarities between each pair of plants. You can use a spreadsheet program like Excel to create this matrix.

Step 4: Calculate the Distance Matrix

Once you have your similarity matrix, you can use it to calculate a distance matrix. The UPGMA algorithm requires a distance matrix as input. The distance between two plants is calculated by subtracting the similarity score from 1.

Step 5: Find the Smallest Value

The next step is to find the smallest value in the distance matrix. This will be the pair of plants that are most closely related. You will then merge these two plants into a single node on the tree.

Step 6: Update the Distance Matrix

After merging the two plants, you will need to update your distance matrix to reflect the new relationships. The distance between the new node and the remaining plants is calculated as the average of the distances from each of the individual plants to the new node.

Step 7: Repeat Steps 5 and 6

You will then repeat steps 5 and 6, finding the smallest value in the updated distance matrix and merging the corresponding nodes, until all the plants are part of the same tree.

Step 8: Draw the Tree

The final step is to draw the UPGMA tree. The length of each branch on the tree represents the distance between the related plants. You can use various software programs such as PhyloTree to create a visual representation of your UPGMA tree.

Conclusion

In conclusion, the UPGMA algorithm is a useful tool for creating phylogenetic trees. By following the steps outlined above, you can create a UPGMA tree for five plants and gain a better understanding of their evolutionary relationships.