Patterning of the central nervous system is regulated by a signaling center located at the midbrain-hindbrain boundary (MHB), or isthmus organizer. Fibroblast growth factors secreted from the MHB are required and sufficient to direct the ordered growth and regionalization of the midbrain and anterior hindbrain. In an unbiased secretion cloning screen of Xenopus gastrula embryos we identified a novel gene, which we designated as Isthmin (xIsm) due to its prominent expression at the MHB. xIsm encodes a secreted protein of 449 amino acids containing one copy of the thrombospondin type 1 repeat (TSR). We also found orthologous Isthmin genes in human (hIsm) and mouse (mIsm), as well as a gene encoding an Isthmin-like human unknown protein (hIsm-l). The conservation of a unique carboxy-terminal region between hIsm and hIsm-l suggests that Isthmin is the founding member of a new family of secreted proteins. xIsm was strongly expressed maternally in the Xenopus egg and showed zygotic expression in the ventral blastopore lip, notochord, and MHB. Additional expression domains were detected in neural crest, ear vesicle, and developing blood islands. Interestingly, xIsm was co-expressed with Fibroblast growth factor-8 (xFgf-8) at multiple sites including the MHB, indicating that these two genes are part of a synexpression group which also includes sprouty and sef homologs.

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Given the attentional and motivational saliency of infant faces, triggered by a set of perceptual baby schema features, other‐ethnicity infant faces may overcome the processing differences associated with the other‐race effect (ORE). Using an attentional bias paradigm, we found that while there was a same‐ethnicity attentional bias for adult faces, there was no difference in attention to same‐ and other‐ethnicity infant faces, suggesting that other‐ethnicity infant faces are equally salient and not subject to the same bias as other‐ethnicity adult faces. To directly measure the ORE, we used a recognition memory test to measure differences between same‐ and other‐ethnicity infant and adult faces. Regardless of age, same‐ethnicity faces were better remembered than other‐ethnicity faces. Further, regardless of ethnicity, adult faces were better remembered than infant faces, a finding consistent with an Other Age Effect. Taken together, these experiments suggest that the saliency of baby schema does not fully overcome the social or perceptual factors leading to the ORE.