“…In this context, adult mammals (Braunitzer et al, 1961;Leclercq et al, 1981) and birds (Rücknagel et al, 1984;Oberthür et al, 1983;Oberthür et al, 1986) have been reported to have one kind of β-globin, but adult frogs (Knöchel et al, 1983;Patient et al, 1983) contained two subtypes of β-globin chains. Due to an inconsistency in the number of subtypes of adult β-type globin-chains among amphibians, reptiles, birds and mammals, reinvestigations are needed, especially, in regards to the evolution of Tetrapoda (Benton, 1990;Hardison, 1998).…”