Why is the study of haemoglobin's primary structure important for understanding evolutionary relationships?

The study of haemoglobin's primary structure is crucial for understanding evolutionary relationships because it provides insight into the genetic changes and mutations that have occurred over time across different species. The primary structure of haemoglobin, which consists of the sequence of amino acids in its polypeptide chains, can vary between species due to evolutionary processes. By comparing these sequences, scientists can identify specific mutations and infer how closely related different species are to one another. This molecular evidence can complement fossil records and morphological data, providing a clearer picture of evolutionary lineages and the divergence of species.

In this context, examining haemoglobin sequences can help establish phylogenetic trees, revealing common ancestors and evolutionary paths. Such comparisons also highlight how certain adaptations in haemoglobin, possibly related to variations in oxygen transport efficiency, align with different environmental pressures experienced by various species.