Phylogenetic Distribution of the Change in Hemoglobin Forms with Morphogenesis

In amphibians the switch from synthesis of fetal hemoglobins to synthesis of adult hemoglobins is unquestionably under the control of thyroxin, like other processes of metamorphosis (Moss and Ingram, 1965), although this takes place at the level of erythro-poiesis and not at the level of young circulating erythrocytes, which continue to synthesize in accordance with their predetermined program. 

A number of comparative studies have been made of fetal and adult hemoglobins of chickens and other domestic birds (Fraser, 1961 Wilt, 1962 Manwell et al., 1963). 

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