84 (Suppl EHA‐4), 1–3.
3 3 Palis J (2016) Hematopoietic stem cell‐independent hematopoiesis: emergence of erythroid, megakaryocytic, and myeloid potential in the mammalian embryo. FEBS Lett, 590, 3965–3974.
4 4 de Bruijn MF, Speck NA, Peeters MC and Dzierzak E (2000) Definitive hematopoietic stem cells first develop within the major arterial regions of the mouse embryo. EMBO J, 19, 2465–2474.
5 5 Ivanovs A, Rybtsov S, Welch L, Anderson RA, Turner ML and Medvinsky A (2011) Highly potent human hematopoietic stem cells first emerge in the intraembryonic aorta‐gonad‐mesonephros region. J Exp Med, 208, 2417–2427.
6 6 Ivanovs A, Rybtsov S, Anderson RA, Turner ML and Medvinsky A (2014) Identification of the niche and phenotype of the first human hematopoietic stem cells. Stem Cell Reports, 2, 449–456.
7 7 Marshall CJ and Thrasher AJ (2001) The embryonic origins of human haematopoiesis. Br J Haematol, 112, 838–850.
8 8 O’Byrne S, Elliott N, Rice S, Buck G, Fordham N, Crump NT et al. (2019) Discovery of a CD10 negative B‐progenitor in human fetal life identifies unique ontogeny‐related developmental programs. Blood, 134, 1059–1071.
9 9 Popescu D‐M, Botting RA, Stephenson E, Green K, Jardine L, Acres M et al. (2019) Decoding the development of the blood and immune systems during human fetal liver haematopoiesis. Nature, 574, 365–371.
10 10 Migliaccio, AG., Migliaccio AR, Petti S, Mavilio F, Russo G, Lazzaro D et al. (1986) Human embryonic hemopoiesis. Kinetics of progenitors and precursors underlying the yolk sac–liver transition. J Clin Invest, 78, 51–60.
11 11 Tavian M, Hallais MF and Peault B (1999) Emergence of intraembryonic hematopoietic precursors in the pre‐liver human embryo. Development, 126, 793–803.
12 12 Charbord P, Tavian M, Humeau L and Peault B (1996) Early ontogeny of the human marrow from long bones: an immunohistochemical study of hematopoiesis and its microenvironment. Blood, 87, 4109–4119.
13 13 Benz C, Copley MR, Kent DG, Wohrer S, Cortes A, Aghaeepour N et al. (2012) Hematopoietic stem cell subtypes expand differentially during development and display distinct lymphopoietic programs. Cell Stem Cell, 10, 273–283.
14 14 Yuan J, Nguyen CK, Liu X, Kanellopoulou C and Muljo SA (2012) Lin28b reprograms adult bone marrow hematopoietic progenitors to mediate fetal‐like lymphopoiesis. Science, 335, 1195–1200.
15 15 Copley MR, Babovic S, Benz C, Knapp DJHF, Beer PA, Kent DG et al. (2013) The Lin28b‐let‐7‐Hmga2 axis determines the higher self‐renewal potential of fetal haematopoietic stem cells. Nat Cell Biol, 15, 916–925.
16 16 Jardine L, Webb S, Goh I, Quiroga Londoño M, Reynolds G, Mather M et al. (2021) Intrinsic and extrinsic regulation of human fetal bone marrow haematopoiesis and perturbations in Down syndrome. Nature, 598, 327–331.
17 17 Roy A, Wang G, Iskander D, O’Byrne S, Elliott N, O’Sullivan J et al. (2021) Developmental stage‐ and site‐specific transitions in lineage specification and gene regulatory networks in human hematopoietic stem and progenitor cells. Cell Rep, 36, 109698.
18 18 Bowie MB, Kent DG, Dykstra B, McKnight KD, McCaffrey L, Hoodless PA and Eaves CJ (2007) Identification of a new intrinsically timed developmental checkpoint that reprograms key hematopoietic stem cell properties. Proc Natl Acad Sci U S A, 104, 5878–5882.
19 19 Ranzoni AM, Tangherloni A, Berest I, Riva SG, Myers B, Strzelecka PM et al. (2021) Integrative single‐cell RNA‐Seq and ATAC‐Seq analysis of human developmental hematopoiesis. Cell Stem Cell, 28, 472–487.e7.
20 20 Mascarenhas MI, Parker A, Dzierzak E and Ottersbach K (2009) Identification of novel regulators of hematopoietic stem cell development through refinement of stem cell localization and expression profiling. Blood, 114, 4645–4653.
21 21 Chou S, Flygare J and Lodish HF (2013) Fetal hepatic progenitors support long‐term expansion of hematopoietic stem cells. Exp Hematol, 41, 479–490.
22 22 Hock H, Hamblen MJ, Rooke HM, Schindler JW, Saleque S, Fujiwara Y and Orkin SH (2004) Gfi‐1 restricts proliferation and preserves functional integrity of haematopoietic stem cells. Nature, 431, 1002–1007.
23 23 Hock H, Meade E, Medeiros S, Schindler JW, Valk PJ, Fujiwara Y and Orkin SH (2004) Tel/Etv6 is an essential and selective regulator of adult hematopoietic stem cell survival. Genes Dev, 18, 2336–2341.
24 24 Kim I, Saunders TL and Morrison SJ (2007) Sox17 dependence distinguishes the transcriptional regulation of fetal from adult hematopoietic stem cells. Cell, 130, 470–483.
25 25 Mochizuki‐Kashio M, Mishima Y, Miyagi S, Negishi, Saraya A, Konuma T et al. (2011) Dependency on the polycomb gene Ezh2 distinguishes fetal from adult hematopoietic stem cells. Blood, 118, 6553–6561.
26 26 Pietras EM and Passegue E (2013) Linking HSCs to their youth. Nat Cell Biol, 15, 885–887.
27 27 Rice S, Jackson T, Crump NT, Fordham N, Elliott N, O’Byrne S et al. (2021) A human fetal liver‐derived infant MLL‐AF4 acute lymphoblastic leukemia model reveals a distinct fetal gene expression program. Nat Commun, 12, 6905.
28 28 Böiers C, Richardson SE, Laycock E, Zriwil A, Turati VA, Brown J et al. (2018) A human IPS model implicates embryonic B‐myeloid fate restriction as developmental susceptibility to B acute lymphoblastic leukemia‐associated ETV6‐RUNX1. Dev Cell, 44, 362–377.e7.
29 29 Jackson TR, Ling R and Roy A (2021) The origin of B‐cells: human fetal B cell development and implications for the pathogenesis of childhood acute lymphoblastic leukemia. Front Immunol, 12, 637975.
30 30 Yan H, Hale J, Jaffray J, Li J, Wang Y, Huang Y et al. (2018) Developmental differences between neonatal and adult human erythropoiesis. Am J Hematol, 93, 494–503.
31 31 Dame C, Fahnenstich H, Freitag P, Hofmann D, Abdul‐Nour T, Bartmann P and Fandray J (1998) Erythropoietin mRNA expression in human and neonatal tissue. Blood, 92, 3218–3225.
32 32 Teramo KA, Klemetti MM and Widness JA (2018) Robust increases in Hb by the hypoxic fetus is a response to protect the brain and other organs. Pediatr Res, 84, 807–812.
33 33 Tojo Y, Sekine H, Hirano I, Pan X, Souma T, Tsujita T et al. (2015) Hypoxia signaling cascade for erythropoietin production in hepatocytes. Mol Cell Biol, 35, 2658–2672.
34 34 Watts TL and Roberts IAG (1999) Haematological abnormalities in the growth‐restricted infant. Semin Neonatol, 4, 41–54.
35 35 Brugnara C and Platt OS (2009) The neonatal erythrocyte and its disorders. In: Orkin SH, Nathan DG, Ginsburg D, Look AT, Fisher DE and Lux SE (eds), Nathan and Oski’s Hematology of Infancy and Childhood, 7th edn. WB Saunders, Philadelphia, pp. 21–66.
36 36 Ohls RK (2002) Erythropoietin in extremely low birthweight infants: blood in versus blood out. J Pediatr, 141, 3–6.
37 37 Bain BJ (2020) Haemoglobinopathy Diagnosis, 3rd edn. Wiley Blackwell, Oxford, pp. 2–4.
38 38 King AJ and Higgs DR (2018) Potential new approaches to the management of the Hb Bart’s hydrops fetalis syndrome: the most severe form of α‐thalassemia. Hematology Am Soc Hematol Educ Program 2018, 2018, 353–360.
39 39 Bard H (1975) The postnatal decline in HbF synthesis in normal full‐time infants. J Clin Invest, 55, 395–398.
40 40 Phillips HM, Holland BM, Jones JG, Abdel‐Moiz AL, Turner TL and Wardrop CA (1988) Definitive estimate of rate of hemoglobin switching: measurement of percent hemoglobin F in neonatal reticulocytes. Pediatr Res, 23, 595–597.
41 41 Vinjamur DS, Bauer DE, Orkin SH (2018) Recent progress in understanding and manipulating haemoglobin switching for the haemoglobinopathies. Br J Haematol, 180, 630–643.
42 42 Frangoul H, Altshuler D, Cappellini MD, Chen YS, Domm J, Eustace BK et al. (2020) CRISPR‐Cas9 gene editing for sickle cell disease and β‐thalassemia. N Engl J Med, 384, 252–260.
43 43 Kuruvilla DJ, Widness JA, Nalbant D, Schmidt RL, Mock DM, An G and Veng‐Pedersen P (2017) Estimation of adult and neonatal