Convergent evolution of hemoglobin switching in jawed and jawless vertebrates

BMC Evolutionary Biology

Research Article

Margaret F. Docker¹  Kim Rohlfing²  Friederike Stuhlmann²  Thorsten Burmester² 

[1] Department of Biological Sciences, University of Manitoba, 50 Sifton Road, R3T 2N2, Winnipeg, MB, Canada;Institute of Zoology, University of Hamburg, Martin-Luther-King-Platz 3, D-20146, Hamburg, Germany;

关键词: Agnatha;    Ammocoete;    Gene family;    Hemoglobin switching;    Myoglobin;    Ontogeny;    Oxygen;    Phylogeny;   

DOI  :  10.1186/s12862-016-0597-0

 received in 2015-10-12, accepted in 2016-01-19,  发布年份 2016

来源: Springer

【 摘 要 】

BackgroundDuring development, humans and other jawed vertebrates (Gnathostomata) express distinct hemoglobin genes, resulting in different hemoglobin tetramers. Embryonic and fetal hemoglobin have higher oxygen affinities than the adult hemoglobin, sustaining the oxygen demand of the developing organism. Little is known about the expression of hemoglobins during development of jawless vertebrates (Agnatha).ResultsWe identified three hemoglobin switches in the life cycle of the sea lamprey. Three hemoglobin genes are specifically expressed in the embryo, four genes in the filter feeding larva (ammocoete), and nine genes correspond to the adult hemoglobin chains. During the development from the parasitic to the reproductive adult, the composition of hemoglobin changes again, with a massive increase of chain aHb1. A single hemoglobin chain is expressed constitutively in all stages. We further showed the differential expression of other globin genes: Myoglobin 1 is most highly expressed in the reproductive adult, myoglobin 2 expression peaks in the larva. Globin X1 is restricted to the embryo; globin X2 was only found in the reproductive adult. Cytoglobin is expressed at low levels throughout the life cycle.ConclusionBecause the hemoglobins of jawed and jawless vertebrates evolved independently from a common globin ancestor, hemoglobin switching must also have evolved convergently in these taxa. Notably, the ontogeny of sea lamprey hemoglobins essentially recapitulates their phylogeny, with the embryonic hemoglobins emerging first, followed by the evolution of larval and adult hemoglobins.

【 授权许可】

CC BY   
© Rohlfing et al. 2016