Transition from Gamma to Beta globin during pre- and post-partum development
Hemoglobin is a tetrameric oxygen-transport molecule, in adults comprising two alpha chains (
) and two beta chains (
). In early fetal ciruclation, hemoglobin tetramers include the gamma globin (
) chainin place of the beta. The gamma is part of the same gene family as beta, and provides more optimal O2 binding under the partial pressure conditions of the fetal circulation. The beta globin replaces the gamma globin
towards and shortly after birth: one difficulty faced by premature
infants is the suboptimal composition of circulating hemoglobin. Note
that other globin types are present in very early development: the zeta chain (
) is replaced by alpha, and the epsilon chain (
) by gamma, then beta.
) and two beta chains (). In early fetal ciruclation, hemoglobin tetramers include the gamma globin () chainin place of the beta. The gamma is part of the same gene family as beta, and provides more optimal O2 binding under the partial pressure conditions of the fetal circulation. The beta globin replaces the gamma globin
towards and shortly after birth: one difficulty faced by premature
infants is the suboptimal composition of circulating hemoglobin. Note
that other globin types are present in very early development: the zeta chain () is replaced by alpha, and the epsilon chain () by gamma, then beta.Figure © 2000 by Griffiths et al. ; text © 2006 by Steven M. Carr