Is the Gram staining result a good indicator of the phylogen

Is the Gram staining result a good indicator of the phylogenetic relationship between bacteria? Explain.

Solution

Gram staining is a very routinely used common practise to distinguish morphologically between different types of bacteria. In this staining, gram positive cells stain blue whereas gram negative cells stain pinkish red based upon the composition of their cell wall. Hence, this also gives an indication about their physiological functions and phylogenetic relationships.

Studies have shown that decendents of primitive gram positive or negative bacteria stain in a similar way as expected shown a clear phylogenetic decendency among these microbes. However, there are indeed certain exceptions to it which can be misleading. For example, certain archaeal bacteria stain false gram positive owing to their differential composition of cell membrane. Similarly, some bacteria expected to be gram negative stain gram positive for similar reasons.

Thus, although gram staining is a very informative process, it should always be combined with some more robust and supportive methods to identify a microbe and establish a phylogenetic relationship among microbes.