The yolk sac is situated on the ventral aspect of the embryo and is one of the three embryonic cavities (chorion, amnion and yolk sac) that appear as of day 8 of human development. The definitive yolk sac structure consists of a double-layered extraembryonic membrane with hypoblast-derived endoderm on the inside and mesoderm on the outside. The combination of endoderm and mesoderm layers is called splanchnopleure and appears in both the yolk sac and allantois.. The endodermal tissue supplies functioning epithelial cells, while the mesoderm generates the essential blood supply to and from this epithelium. Additionally, the outer mesodermal layer of the yolk sac constitutes an important site of hematopoiesis in the developing embryo. The yolk sac cavity is filled with fluid called the vitelline fluid. In humans, the yolk sac normally disappears before birth (its residues are rarely found postnatally, as an anomaly called Meckels diverticulum). Nutients are absorbed from the yolk sac through a ...
Tissue factor (TF) triggers blood coagulation and is translated from two mRNA splice isoforms, encoding membrane-anchored full-length TF (flTF) and soluble alternatively-spliced TF (asTF). The complete knockout of TF in mice causes embryonic lethality associated with failure of the yolk sac vasculature. Although asTF plays roles in postnatal angiogenesis, it is unknown whether it activates coagulation sufficiently or makes previously unrecognized contributions to sustaining integrity of embryonic yolk sac vessels. Using gene knock-in into the mouse TF locus, homozygous asTF knock-in (asTFKI) mice, which express murine asTF in the absence of flTF, exhibited embryonic lethality between day 9.5 and 10.5. Day 9.5 homozygous asTFKI embryos expressed asTF protein, but no procoagulant activity was detectable in a plasma clotting assay. Although the α-smooth-muscle-actin positive mesodermal layer as well as blood islands developed similarly in day 8.5 wild-type or homozygous asTFKI embryos, ...
Vertebrate hematopoietic stem cells are derived from vental mesoderm, which is postulated to migrate to both extra- and intraembryonic positions during gastrula and neurula stages. Extraembryonic migration has previously been documented, but the origin and migration of intraembryonic hematopoietic cells have not been visualized. The zebrafish and most other teleosts do not form yolk sac blood islands during early embryogenesis, but instead hematopoiesis occurs solely in a dorsal location known as the intermediate cell mass (IM) or Oellacher. In this report, we have isolated cDNAs encoding zebrafish homologs of the hematopoietic transcription factors GATA-1 and GATA-2 and have used these markers to determine that the IM is formed from mesodermal cells in a posterior-lateral position on the yolk syncytial layer of the gastrula yolk sac. Surprisingly, cells of the IM then migrate anteriorly through most of the body length prior to the onset of active circulation and exit onto the yolk sac. These ...
De la chapelle, A; Fantoni, A; and Marks, P A., "Differentiation of mammalian somatic cells, dna and hemoglobin synthesis in fetal mouse yolk sac erythroid cells." (1969). Subject Strain Bibliography 1969. 1375 ...
Supply of lipids from the mother is essential for fetal growth and development. In mice, disruption of yolk sac cell secretion of apolipoprotein (apo) B-containing lipoproteins results in embryonic lethality. In humans, the yolk sac is vestigial. Nutritional functions are instead established very early during pregnancy in the placenta. To examine whether the human placenta produces lipoproteins, we examined apoB and microsomal triglyceride transfer protein (MTP) mRNA expression in placental biopsies. ApoB and MTP are mandatory for assembly and secretion of apoB-containing lipoproteins. Both genes were expressed in placenta and microsomal extracts from human placenta contained triglyceride transfer activity, indicating expression of bioactive MTP. To detect lipoprotein secretion, biopsies from term placentas were placed in medium with [(35)S]methionine and [(35)S]cysteine for 3-24 h. Upon sucrose gradient ultracentrifugation of the labeled medium, fractions were analyzed by ...
During development, the hematopoietic lineage transits through hemogenic endothelium, but the signaling pathways effecting this transition are incompletely characterized. Although the Hedgehog (Hh) pathway is hypothesized to play a role in patterning blood formation, early embryonic lethality of mice lacking Hh signaling precludes such analysis. To determine a role for Hh signaling in patterning of hemogenic endothelium, we assessed the effect of altered Hh signaling in differentiating mouse ES cells, cultured mouse embryos, and developing zebrafish embryos. In differentiating mouse ES cells and mouse yolk sac cultures, addition of Indian Hh ligand increased hematopoietic progenitors, whereas chemical inhibition of Hh signaling reduced hematopoietic progenitors without affecting primitive streak mesoderm formation. In the setting of Hh inhibition, induction of either Notch signaling or overexpression of Stem cell leukemia (Scl)/T-cell acute lymphocytic leukemia protein 1 rescued hemogenic ...
In this study, the Gpr107 locus was disrupted by using a BAC-mediated gene targeting strategy. Gpr107 ablation had profound consequences for embryogenesis, resulting in a loss of viability between 11.5 and 12.5 days post-coitus. Transcript abundance profiling through sequencing identified selective defects in cubilin-megalin-related trafficking, which appeared to contribute to or account for the observed embryonic lethality. Cubilin gene expression was prominently diminished at E10.5, the start of the critical period for Gpr107 homozygote survival.. Previous data have shown that the multi-ligand endocytic receptors cubilin and megalin exert their roles in the visceral epithelial cells of the embryonic yolk sac, intestine, kidney and thyroid gland and participate in the transportation of vitamins B12 and D3, lipid-binding proteins, poorly water soluble hormones and their binding proteins, mineral-binding proteins and a variety of heterogeneous ligands (Kaseda et al., 2011; Kozyraki et al., 1999; ...
Childhood CNS germ cell tumors form in germ cells, which are cells that develop into sperm or ova (eggs). There are different types of childhood germ cell tumors. These include germinomas, embryonal yolk sac carcinomas, choriocarcinomas, and teratomas. A mixed germ cell tumor has two types of germ cell tumors in it. Germ cell tumors can be either benign or malignant.. Germ cell brain tumors usually form in the center of the brain, near the pineal gland. The pineal gland is a tiny organ in the brain that makes melatonin, which is a substance that helps control the sleeping and waking cycle. Germ cell tumors can spread to other parts of the brain and spinal cord.. ...
Introduction Cell lineages arise during development Ectodermal tissues Mesodermal tissues Endodermal tissues EBs resemble the embryo of the egg- cylinder stage Neuronal cells Cardiac muscle cells Hematopoietic cells Yolk sac cells ES cells have full developmental potential EBs from ES cells EBs consist of: Later stages EBs are composed of:
Question - Pregnancy ultrasound showing gestational sac with yolk sac, no embryo. Should I worry? Any problem with the baby?. Ask a Doctor about Yolk sac, Ask an OBGYN, Maternal and Fetal Medicine
Hematopoietic precursors have been obtained from hES cells by either co-culturing or by inducing them with growth factors. In the first study to isolate blood cell progenitors from hES cells, Kaufman et al. (Kaufman et al., 2001) cultured ES cells on marrow stromal or yolk sac-derived cell lines, and monitored the culture for the expression of blood cell lineage markers, such as CD34. The appearance of CD34+ cells peaked at 17 days, at a level of 1-2% of the total cells, and declined thereafter; these cells were also CD45- (a general marker for hematopoetic cells), but many were CD31+ (a marker of the endothelial lineage). These progenitors could form both erythroid and myeloid colonies in agar. The expression of adult and fetal hemoglobin, but not embryonic globin, was observed during erythroid differentiation.. Chadwick et al. (Chadwick et al., 2003) used a combination of embryoid body formation and treatment with various hematopoietic cytokines, plus BMP4, to induce the formation of ...
If youre on any medications, ask your doctor whether they pose any risk to your growing baby. Whitish yellow or frothy, could be a sign of infection. Also, your growing uterus exerts additional pressure on your bladder thereby causing you to urinate more often. Carefully cut the puzzle anx. I hope things get better. There is a great pregnancy yolk sac and fetal pole of vital information you need to know, and the more knowledgeable you are about your condition, the more prepared and relaxed youll feel. I was a nursing home social worker and I worked with the Hospice staff a lot. The pregnancy yolk sac and fetal pole found a trend that pregnant women tended to rate odors as more intense during their first trimester. There are chemically-produced drugs available for people who prefer to reduce the discomfort and pain. You have just road travelling during pregnancy first trimester a lot of advise on being pregnant. Thanks for the positive response on the hub. If your regular cycle is missing, yol, ...
Heart- and neural crest derivatives-expressed protein 1 is a protein that in humans is encoded by the HAND1 gene. A member of the HAND subclass of basic Helix-loop-helix (bHLH) transcription factors, the Heart and neural crest-derived transcript-1 (HAND1) gene is vital for the development and differentiation of three distinct embryological lineages including the cardiac muscle cells of the heart, trophoblast of the placenta, and yolk sac vasculogenesis. Most highly related to twist-like bHLH genes in amino acid identity and embryonic expression, HAND1 can form homo- and heterodimer combinations with multiple bHLH partners, mediating transcriptional activity in the nucleus. The protein encoded by this gene belongs to the basic helix-loop-helix family of transcription factors. This gene product is one of two closely related family members, the HAND proteins are expressed within the developing ventricular chambers, cardiac neural crest, endocardium (HAND2 only) and epicardium (HAND2 only) . HAND1 ...
This animation shows the early development of endoderm forming the gastrointestinal tract, yolk sac and allantois. The movie starts approximately week 3 and continues through week 4. Yellow shows the general lining of the yolk sac (bottom), continuous with the endoderm of the trilaminar embryonic disc (top) during week 3. As the trilaminar disc folds in this week, the foregut and hindgut regions become separated from the external yolk sac. The midgut region remains open to the yolk sac and will separate later. Foregut - Begins at the buccopharyngeal membrane, the foregut region in the head is now called the pharynx. At the lower end of the pharynx a ventral bud forms, that will later form the respiratory tract. Beneath this region the tube grows rapidly forming a dilation of the tube, that will later form the stomach. Beneath this region is the boundary of the foregut and ventrally lies the transverse septum. Midgut - Broadly open to the external yolk sac then with continued folding narrows to a ...
Vertebrate haematopoietic stem cells (HSCs) ensure continuous haematopoietic cell production throughout life. HSCs can be defined by their dual ability to self-renew, thereby maintaining their numbers, and to differentiate into all lineages of the blood and immune system (Dykstra et al., 2007). Blood cells first appear in the mammalian conceptus, in the extraembryonic yolk sac, concomitant with the developing vasculature. These early haematopoietic progenitors are, however, of more limited potency than adult HSCs. In mice, HSCs that confer complete, long-term, multilineage haematopoietic repopulation of irradiated recipient mice first appear at embryonic day (E)10.5 in the aorta-gonad-mesonephros (AGM) region of the embryo body and the placenta, and they seed the fetal liver and the adult bone marrow. There is a rapid and permanent perinatal shift of the entire haematopoietic system to the bone marrow (Mikkola and Orkin, 2006; Dzierzak and Speck, 2008).. The decisions of HSCs to self-renew or ...
In these animals the developing embryo shows small allantois. It will never come in contact with chorion. Their yolk sac was large. It comes in contact with chorin. This part will gain blood vessels. This part will come in contact with endometrium of uterus. This is only a contact, but not fusion. Through this contact the embryo will absorb nourishment from mother. This is called chorio vitelline placenta or Yolk sac placenta ...
The heart begins as an endocardial tube that forms in front of the prochordal plate from bilateral angiogenic cell clusters located between the cardiogenic plate and the underlying yolk sac endoderm. The cardiogenic plate is a thickened layer of splanchnic mesoderm that will give rise to the epimyocardium. With the formation of the head fold and the expansion of the prosencephalon, the cardiogenic plate assumes a position ventral to the foregut. The angiogenic cell clusters become a pair of endothelial tubes in the splanchnic mesodermal layer and bulge into the pericardial part of the embryonic coelom. With formation of the lateral body folds, the paired endothelial tubes fuse in the midline producing a single endocardial tube ventral to the foregut ...
Yolk sac is the first anatomical structure identified within the gestational sac. It plays a critical role in embryonal development by providing nutrients, serving as the site of initial haematopoiesis, providing endocrine, metabolic and immunolo...
We have developed conditions for studying the binding, uptake, degradation and transport of 125I-labelled IgG by yolk sac in vitro. Specific binding to tissue at 4 degrees C and to paraformaldehyde-treated tissue at 37 degrees C was time- and temperature-dependent and showed saturation kinetics (Kd,4 degrees C = 2.9 × 10(-6) M, Kd,37 degrees C = 5.3 × 10(-6) M). Uptake was studied at 37 degrees C using untreated tissue (K uptake = 13.3 × 10(-6) M) and was inhibited by preincubation with metabolic poisons but not with cycloheximide. Tissue that had been incubated with 125I-labelled IgG at 37 degrees C released radiolabelled degradation products and intact 125I-labelled IgG into the medium. Experiments with paraformaldehyde-treated and untreated tissue showed that release of intact 125I-labelled IgG was mostly the result of ligand dissociation from surface binding sites. However, more 125I-labelled IgG was released from untreated tissue than could be accounted for solely by loss of ...
The appearance of the yolk sac in the Thomson ovum isvery much like that shown in Stieves illustration. On Prof. J. P. Hills advice I ventured to send the serial microphotographs of this ovum to Prof. Grosser, and he was kind enough to give me his opinion on this point after examining them. His criticism of both the Thomson and the Stieve specimen is the same. Inboth, according to him, the entodermal lining of the yolk sac has disappeared except under the disc. I confess I think this explanation is a difficult one. Allowing that 26 hours elapsed between the womans death and the fixation of the Thomson ovum, the entoderm could scarcely have vanished in this time without leaving a trace. If the cels had been shed, they or their debris should surely still be found in the yolk sac, unless its walls were broken. But the yolk sac appears to be intact, filed with coagulum, but containing only an occasional detached cel. If there had been a dehiscence in its wall, the fluid content would certainly ...
Question - Chromosomal abnormalities due to an enlarged yolk sac, ultrasound report is normal. Ask a Doctor about uses, dosages and side-effects of Chorionic gonadotropin, Ask an OBGYN, Maternal and Fetal Medicine
intrauterine pregnancy. This should be seen with the transvaginal sonogram by 5 weeks after the last menstrual period. The earliest embryonic structure is the yolk sac, and likewise, this can be seen as early as the end of the 5th week. Evaluating the yolk sac is important because it can point to problems in a pregnancy. If it is not present at this early time, or if the shape is irregular or large, this can be the first sign of a nonviable pregnancy.. …..Near the 6th week from the last menstrual period, the embryo should be seen attached to the yolk sac, and fetal heart activity should be noted between the 6th and 7th week. When the gestational sac is approximately 2 cm, an embryo should be seen, and if it is not identified at this time, a blighted ovum is confirmed.. …..There are specific sonographic signs of a problem pregnancy:. ...
The role of the zebrafish transcription factor Nanog has been controversial. It has been suggested that Nanog is primarily required for the proper formation of the extraembryonic yolk syncytial layer (YSL) and only indirectly regulates gene expression in embryonic cells. In an alternative scenario, Nanog has been proposed to directly regulate transcription in embryonic cells during zygotic genome activation. To clarify the roles of Nanog, we performed a detailed analysis of zebrafish nanog mutants. While zygotic nanog mutants survive to adulthood, maternal-zygotic and maternal mutants exhibit developmental arrest at the blastula stage. In the absence of Nanog, YSL formation and epiboly are abnormal, embryonic tissue detaches from the yolk, and the expression of dozens of YSL and embryonic genes is reduced. Epiboly defects can be rescued by generating chimeric embryos of MZnanog embryonic tissue with wild-type vegetal tissue that includes the YSL and yolk cell. Notably, cells lacking Nanog ...
Surprisingly, hatching time did not change under any conditions. This suggests a degree of "hard wired" embryological development inside the egg. In the case of the hypoxic hatchlings, they came out "almost done." While all three groups had remnants of a yolk sac upon hatching, the hypoxic hatchlings actually had the yolk sac still protruding (normal and hyperoxic hatchlings just showed distended bellies). In some cases, the yolk sac was larger around than the hind legs, thus making movement clumsy and cumbersome.. Other interesting results from this study, included notable changes to the cardiopulmonary system. Hypoxic hatchling lungs were actually smaller than the lungs of normal hatchlings; which appears counterintuitive. The heart, meanwhile, showed distinct hypertrophy in hypoxic animals. The authors believe that lack of lung growth in hatchlings may have been due to the fact that lung function does not start until after hatchlings have hatched.? The heart, on the other hand, is hard at ...
Thank you all for your love, support, and prayers during this nerve wracking time. This morning we had our first ultrasound. The ultrasound tech was amazingly kind and understanding. She must have read my chart because she knew that I would be anxious. She started off by saying we wanted to see a gestation sac and yolk sac today and if we saw a fetal pole that would be extra. As soon as she put the ultrasound probe in she let me know that she saw a great looking yolk sac and a baby with a heartbeat! Baby measured on track for 5w6d and had a heart rate of 93. The Dr told me that the heart rate is on the low side of normal, but ok since we are so early. The babys heart only started beating recently and the SA node (electrical center that sets the rate of the heart) is still immature. In the first few days the fetal heart rate can be lower than what we would expect in a week. Here are some pictures ...
The C166-GFP cell line was derived from the C166 cell line (ATCC CRL-2581) by transfection with a plasmid reporter vector, pEGFP-N1, encoding enhanced green fluorescent protein (GFP). The vector was obtained from Clontech, Palo Alto, CA (#6085-1). The C166 cell line was established from cells from F1 embryos obtained by mating a female NMRI/GSF mouse with a male CD-1 mouse that was transgenic for the human fes (fps/fes) proto-oncogene.
This egg hatched on its on this morning and has a grayish/yellowish blob hanging out on its lower stomach with a skinny red vessel/cord hanging from...
I need some advice. This was my first try at incubating eggs. Yesterday was 21 days and 3 out of 28 eggs hatched - one has about a pea sized bubble...
i am 10 weeks pregnant but since my first ultrasound at 7 weeks, heartbeat was not seen..then i did 2nd at 9 weeks still no heart beat then finally i did my 3rd u/s yesterday at 10 weeks n there was n...
Things started out a bit on the scary-end of the scale for us as we went in for our 7 week viability appointment only to have the sonographer and perinatologist say the baby was measuring much smaller than it should. Instead of showing a yolk-sac size appropriate to the estimated date of conception - which is initially based off of the first day of the last menstrual cycle and then confirmed by ultrasound - the yolk-sac size was measuring closer to 5 weeks of gestation. Asking to repeat the test in one week, we went back in with hopes of getting better numbers… unfortunately still measuring small the doctors prepared us for the higher probability of a miscarriage… something, you can imagine, we were terrified to hear. Repeating the ultrasound again the following week as requested, the numbers were at least showing consistent growth from one week to the next so the doctors felt at least comfortable enough to grant us a due date two weeks later than initially expected: February 21. ...
Only gestation sac visible at 6 weeks 2 days. No yolk sac or fetal pole no heartbeat seen Sonographer says more likely blighted ovum need to wait for 10 days to do Another sonography to confirm. No bleeding till date only little abdominal pain talking progesterone injection every week since 3 weeks Just thinking What to do ?
I am still non the wiser. The MW did an internal scan and could only see a sac. Had lots of trouble finding anything so I demanded a doctor. Basically the sac has grown, there is now a yolk sac and maybe a heartbeat but cant be 100%. She thinks she sees the start of a fetal pole and it all measured 6.1weeks with doc and 6.5 weeks with the MW. I CANT BE THAT LITTLE!!! I got my BFP on the 18th July so could someone please tell me im right saying that its unlikely im less than 7.3 weeks???? We have to be re-scanned on the 27th. Please give me opinions and yet again thanks for the massive support ...
To be baby, the blastocyst is now called embryo and has reached uterus where it will stay connected to its mother until delivery. Now it undergoes the great division and splits into 2 groups. First half will become son or daughter while the other half will become the placenta (babys lifeline). The water bag,i.e amniontic sac, is forming and so is the yolk sac, which later gets incorporated into babys developing digestive tract. The 3 layers of embryo is getting to grow into specialized parts of the tiny body ...
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I really didnt want to be posting this type of post in the group. I know it leads to a lot of worry for you mommas but I also feel like I need to acknowledge it as well. Went in today for my first u/s at 7w5d and she couldnt see anything with the abdominal u/s so she had me empty my bladder and we did the t/v u/s. We could see the sac but only a yolk sac -an oversized one at that and no fetal pole or anything. :( So guess it was a blighted ovum. She didnt actually use that term, she just called it a MMC. She gave me the option of a dnc or waiting it out. Not sure quite yet, I had a dnc in Aug 2009 after a MMC at 10 wk ( baby measured 8.5). This time, no baby! I had symptoms like fatigue and sore breasts but no major nausea and no vomiting. Im so thankful to have my healthy 3 yr old and will give her lots of extra hugs tonight. Best of luck to you ladies. I hope you have a healthy and happy 9 months and wishing you all adorable and gorgeous babies! Hopefully I can get to trying again in just a few
Daisy - My first beta was 14dp3dt # 324. Then I just had my 2nd beta on 7/6 10,078. I think that was 22dp3dt. RE felt the first one was a good #, and waited a week for a second beta. That was very nerve racking to me, since the last cycle my 2nd beta went down. I thought most RE test every couple of days. I did have an US and it showed one yolk sac. I was worried, since we transferred 3 embryos. Triplets would scare me, twins would have been cute. To be honest I suffer from hypertension already ever since my DD pregnancy. That pregnancy I had borderline pre-eclampsia. I never fully lost all the weight, which makes your BP go up. Since I had 5 attempts of IVF, I guess because of the meds I had gained 40 lbs in one year ...
Last week I had my blood drawn and my progesterone and estrogen dropped by half, Im suppose to be 6 wks. So this freaked me out and i had Dr do an US all they saw was a yolk sac and I was told I was 5wks 2days, how is this when i know the day I got pregnant, did the embryo implant late ??? My hcg was 6884 and i go in today for another hcg. Any words for me ...
I had my first U/S on 10/28/11 and was 6w1d pregnant, but the U/S measured 5w1d with a normal yolk sac, but no baby. My Dr. was not concerned but scheduled a follow-up U/S in 2 weeks, which I just had...
Here is a brief history of my husbands journey: 3/2016 R/O; Afp 89 and hcg10 before surgery ; Pathology:non sem. 90% embryonal 10% yolk sac No signs of invasion
The life stage of a young salmon from independence of the yolk sac as the primary source of nutrition to dispersal from the redd. ...
Anastacia se včera zúčastnila předávání cen GQ Awards MEN OF THE YEAR 2013, kde se stala hrdou majitelkou jedné ze sošek. Po červeném koberci se prošly hvězdy jako David Beckham, Jean Paul Gaultier, Kylie Minogue a také Anastacia, na kterou čekali reportéři s otázkou, jaké je to být zpět mezi světly reflektorů. [přehrát video] V průběhu galavečera Anastacia předvedla, že zpívat rozhodně nezapomněla. Na pódiu zazářila se svými hity Paid My Dues a Left Outside Alone. Záznam včerejší show bude dnes po desáté hodině večerní vysílat německá televizní stanice Pro7Maxx. Sledovat vysílání můžete i online, abyste se nepřipravili o skvělý zážitek vidět Anastacii opět na pódiu.
The space enclosed by the peritoneum. It is divided into two portions, the greater sac and the lesser sac or omental bursa, which lies behind the STOMACH. The two sacs are connected by the foramen of Winslow, or epiploic foramen. . ...
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How much is too much? I walked around my cul de sac for 40 minutes in the am and 40 minutes in the evening. I would go when it was cooler not in the heat of mid day,. My neighbors say they miss seeing me walk my route. I.... ...
Hemoglobin subunit epsilon is a protein that in humans is encoded by the HBE1 gene. The epsilon globin gene (HBE) is normally expressed in the embryonic yolk sac: two epsilon chains together with two zeta chains (an alpha-like globin) constitute the embryonic hemoglobin Hb Gower I; two epsilon chains together with two alpha chains form the embryonic Hb Gower II. Both of these embryonic hemoglobins are normally supplanted by fetal, and later, adult hemoglobin. The five beta-like globin genes are found within a 45 kb cluster on chromosome 11 in the following order: 5 - epsilon - gamma-G - gamma-A - delta - beta - 3. Hemoglobin Human β-globin locus GRCh38: Ensembl release 89: ENSG00000213931 - Ensembl, May 2017 GRCm38: Ensembl release 89: ENSMUSG00000052217 - Ensembl, May 2017 "Human PubMed Reference:". "Mouse PubMed Reference:". Higgs DR, Vickers MA, Wilkie AO, Pretorius IM, Jarman AP, Weatherall DJ (May 1989). "A review of the molecular genetics of the human alpha-globin gene cluster". Blood. ...