Multiple sequence alignment of the conserved N-terminal region of labrid vitellogenins (Crvtg: goldsinny wrasse, Cevtg: rock cook; Lmvtg: cuckoo wrasse) in relation to expressed variants in chicken (GgvtgI, GgvtgII, GgvtgIII) and medaka (OlvtgAa1, OlvtgAa2, OlvtgAb, OlvtgC). Sequences are arranged according to orthology (VtgII/VtgAa, VtgIII/VtgAb, VtgI/VtgC). The boxed residues represent the Vtg receptor minimal interaction domain identified for tilapia by Li et al. . See materials and methods for explanation of the novel OlvtgAa2 sequence, and Additional file 1 for accession numbers used in the study.