During the maturation of HE to pre-HSC/HSC, concomitant with decreasing Notch1 and increasing Notch2 expression, expression of Notch target genes Hey1/Hey2, required for arterial EC fates41, are downregulated, and Notch target gene Cdca7, which regulates HSC emergence56, is increased. Here, HEY2 is linked to hereditary elliptocytosis.