The evolutionary history of globin genes: Insights from marsupials and monotremes

Abstract

Haemoglobin, which is required for oxygen transportation in the blood, is encoded by members of the alpha (α) and beta (β) globin gene families. They are highly regulated throughout different stages of development in a tissue-specific manner. The number and type of α- and β-globin genes varies between jawed vertebrates. In teleosts and amphibians α- and β-like globin genes are clustered together, but in birds and mammals these genes form distinct clusters on different chromosomes. This chapter reviews how data from marsupials and monotremes have contributed in discovering novel globin genes, which in turn has clarified how globin genes have evolved throughout amniote evolution. We also provide a detailed view of how the duplication of a single primordial globin gene (about 500 million years ago) along with other subsequent events have resulted in more complex α- and β-globin clusters in extant vertebrates. In addition, how this has impacted the current fate and regulation of α- and β-genes in mammals will also be discussed.