Three: Blastula Period (2.25-5.25h)
We use the term blastula to refer to the period when the blastodisc begins to look ball-like, at the 128-cell stage, or eighth zygotic cell cycle, and until the time of onset of gastrulation,ca. cycle 14.
斑马鱼的特点
• • • • • • 成年鱼个体小，易于饲养 发育快速、性成熟期短、繁殖力强 胚胎体外发育，易于观察和操作 较完善的胚胎和遗传学操作技术 基因组序列的注释已经完成 品系资源丰富
Stages of Embryonic Development of the Zebrafish
Seven Broad Zygote Cleavage Blastula Gastrula Segmentation Pharyngula Hatching
Stages During the Cleavage Period
Two-cell stage (0.75h) Four-cell stage (1 h) Eight-cell stage (1.25h) Sixteen-cell stage (1.5h) Thirty two-cell stage (1.75h) Sixty four-cell stage (2 h)
Stages During the Zygote Period
One-cell stage
The zygote period. A:a few minutes after fertilization. B:about 10 min after fertil-i zation.
Two: Cleavage Period (0.75-2.25h)
Stages of Embryonic Development of the Zebrafish
刘永飞 20121902004
斑马鱼(Danio rerio)属于辐鳍亚纲(Ac tinop-terygii)鲤科(Cyprinidae)短担尼鱼 属(Danio)的一种硬骨鱼。原产于印度东部、 巴基斯坦、缅甸及孟加拉国的小溪、稻田及 恒河中游地区，是一种常见的热带观赏鱼， 因其体侧具有像斑马一样纵向的暗蓝与银色 相间的条纹而得名。
0-0.75h 0.75-2.25h 2.25-5.25h 5.25-10h 10-24h 24-28h 48-72h
One: Zygote Period (0-0.75h)
1. The newly fertilized egg is in the zygote period until the first cleavage occurs, about 40 minutes after fertilization. 2. The zygote is about 0.7 mm in diameter at the time of fertilization. 3. We include only a single stage called Onecell stage; however many changes are occurring, and one could easily subdivide the period.
Seven: Hatching Period (48-72h)
1. The time of hatching is not useful as a staging index for the zebrafish, in contrast to some other types of embryos, because individuals within a single developing clutch hatch sporadically during the whole 3rd day of development (at standard temperature), and occasionally later. 2. Whether or not an embryo has hatched, its development progresses, hour by hour, and generally individuals that have spontaneously hatched are not more developmentally advanced than ones remaining in their chorions. 3. We arbitrarily call the creatures “embryos” until the end of the 3rd day, and afterward, “larvae,” whether they haver: Gastrula Period (5.25-10h)
The morphogenetic cell movements of involution, convergence, and extension occur, producing the primary germ layers and the embryonic axis.
Face views of embryos during the blastula period. A:256-cell stage(2.5h). B: High stage (3.3h). C:Transition between the high and oblong stages(3.5h). D:Transition between the oblong and sphere stages (3.8h). E:Dome stage (4.3h). F: 30%-epiboly stage (4.7h).
Stages During the Blastula Period
128-cell stage (2.25h) 256-cell stage (2.5h) 512-cell stage (2.75h) lk-cell stage (3 h) High stage (3.25h) Oblong stage (3.66h) Sphere stage (4 h) Dome stage (4.33h) 30%-epiboly stage (4.66h)
斑马鱼的发展史
一. 20世纪70年代初，利用T4噬菌体研究遗传学的 美国俄勒冈大学著名遗传学家George Streisinger注意 到斑马鱼的优点，从宠物店购买了斑马鱼，开始研 究其养殖方法、观察其胚胎发育过程、发展一些相 关的遗传学技术。 • 二. 近十年后，他的研究组于1981年在Nature上发 表了第一篇具有深刻影响的论文（Production of clon es of homozygous diploid zebrafish）。在这篇论文中， 他们报导了斑马鱼的体外受精技术、单倍体诱导技 术，建立了纯合品系，并介绍了斑马鱼的第一个自 然突变体——golden。 •
Five: Segmentation Period (10-24h)
1. A wonderful variety of morphogenetic movements now occur, the somites develop, the rudiments of the primary organs become visible, the tail bud becomes more prominent and the embryo elongates. The first cells differentiate morphologically, and the first body movements appear. 2. The tail bud appears at the caudal end of the lengthening axis during the whole time.
Stages During the Pharyngula Period
High-pec stage (42h)
Prim-25 stage (36h)
Prim-12 stage (30h)
Prim-5 stage (24h)
A:Prim-5 stage (24h) ；B:Prim-12 stage (30h) ；F:Prim-25 stage (36h)；H:High-pec stage (42h).
Embryos during the cleavage period. A:Two-cell stage(0.75 h). 8: Four-cell s tage(1 h). C: Eight-cell stage (1.25h). D:Sixteen-cell stage (1.5 h). E:Thirty-two c ell stage(1.75 h). F: Sixty-four cell stage(2 h).
1. After the first cleavage the cells, divide at about 15-minute intervals. 2. The cytoplasmic divisions are meroblastic; they only incompletely undercut the blastodisc, and the blastomeres, or a specific subset of them according to the stage remain interconnected by cytoplasmic bridges. 3. The six cleavages that comprise this period frequently occur at regular orientations so that one can see how many blastomeres are present are by their arrangement; counting them is unneccessary.