Embryo Development Animal Science 434 John Parrish.
-
Upload
arron-kennedy -
Category
Documents
-
view
227 -
download
1
Transcript of Embryo Development Animal Science 434 John Parrish.
![Page 1: Embryo Development Animal Science 434 John Parrish.](https://reader033.fdocuments.net/reader033/viewer/2022042616/56649ece5503460f94bdbf87/html5/thumbnails/1.jpg)
Embryo Development
Animal Science 434
John Parrish
![Page 2: Embryo Development Animal Science 434 John Parrish.](https://reader033.fdocuments.net/reader033/viewer/2022042616/56649ece5503460f94bdbf87/html5/thumbnails/2.jpg)
Timing of Insemination
Species Time of Ovulation Optimal Insemination Time
Cow 29 hr after start End of estrus (12 hr afterof estrus first seen in estrus)
Ewe End of estrus End of 1st day or start of2nd day of estrus
Sow End of estrus End of 1st day or start of2nd day of estrus
Mare 1-2 days before Every other day beginningend of estrus day 3 of estrus
![Page 3: Embryo Development Animal Science 434 John Parrish.](https://reader033.fdocuments.net/reader033/viewer/2022042616/56649ece5503460f94bdbf87/html5/thumbnails/3.jpg)
Errors in Fertilization
• Polyspermy - polyandry»Multiple sperm penetration
» Invertebrates• excess sperm eliminated because sperm centriole
contributes to first embryonic cleavage spindle
»Mammals• Sperm centriole not essential so development
continues but fails early to midpregnancy due to multiploidy• Occurs most often in aged oocytes due to failure
of zona block to polyspermy
![Page 4: Embryo Development Animal Science 434 John Parrish.](https://reader033.fdocuments.net/reader033/viewer/2022042616/56649ece5503460f94bdbf87/html5/thumbnails/4.jpg)
Errors in Fertilization (cont.)
• Polygyny»Multiple maternal pronuclei + 1 paternal
pronuclei
»Artificially created only• Suppress extrusion of the PBII
• Androgenote»Union of 2 paternal pronuclei
»Artificially created only• From pronuclear exchange
![Page 5: Embryo Development Animal Science 434 John Parrish.](https://reader033.fdocuments.net/reader033/viewer/2022042616/56649ece5503460f94bdbf87/html5/thumbnails/5.jpg)
Errors in Fertilization (cont.)
• Gynogenote»Union of 2 maternal pronuclei
»Artificially created• Induced oocyte activation and supression of PBII
extrusion
• Parthenogenesis»Activation of the oocyte without a sperm
»Embryo is either haploid or gynogenesis occurs to form diploid• Platties - sperm activates but then gynogenesis
occurs and sperm extruded from embryo
![Page 6: Embryo Development Animal Science 434 John Parrish.](https://reader033.fdocuments.net/reader033/viewer/2022042616/56649ece5503460f94bdbf87/html5/thumbnails/6.jpg)
Oocyte Development and Fertilization
MPF MPF
MPFMPF
Primary Oocyte
GV-Intact
GVBD (8 hr) Metaphase I
PB-1
Secondary OocyteMetaphase II (21 hr)
Ovulation(29 hr)
LH Surge (0 hr)
![Page 7: Embryo Development Animal Science 434 John Parrish.](https://reader033.fdocuments.net/reader033/viewer/2022042616/56649ece5503460f94bdbf87/html5/thumbnails/7.jpg)
Zona Pellucida
PerivitellineSpace
Oocyte
Ca2+
Sperm Penetration of the
Zona Pellucidaand
Fusion with the Oocyte(30 hr)
![Page 8: Embryo Development Animal Science 434 John Parrish.](https://reader033.fdocuments.net/reader033/viewer/2022042616/56649ece5503460f94bdbf87/html5/thumbnails/8.jpg)
Embryo Development in the Bovine
2 cell (62 hr, day 2)
4 cell (75 hr, day 3) 8 cell (90 hr, day 3)
16 cell (120 hr, day 4)
32 cellMorula
(day 5-6)
Zygote(34 hr, day 1)
TightMorula
(day 6-7)
Early Blastocyst(day 7-8)
Blastocyst (day 7-9)
ExpandedBlastocyst(day 8-10)
HatchedBlastocyst(day 9-11)
CompactionCompactionBlastocoelBlastocoelInner Cell
MassInner Cell
Mass
TrophectodermTrophectoderm
![Page 9: Embryo Development Animal Science 434 John Parrish.](https://reader033.fdocuments.net/reader033/viewer/2022042616/56649ece5503460f94bdbf87/html5/thumbnails/9.jpg)
Fertilization to Cleavage
Polar Body
Zona Pellucida
Pronuclei
Perivitelline Space
ZygoteZygote
Blastomere
![Page 10: Embryo Development Animal Science 434 John Parrish.](https://reader033.fdocuments.net/reader033/viewer/2022042616/56649ece5503460f94bdbf87/html5/thumbnails/10.jpg)
Fertilization to Cleavage
• Imprinting• Maternal Gene Control• Long Cell Cycle
• Imprinting• Maternal Gene Control• Long Cell Cycle
![Page 11: Embryo Development Animal Science 434 John Parrish.](https://reader033.fdocuments.net/reader033/viewer/2022042616/56649ece5503460f94bdbf87/html5/thumbnails/11.jpg)
Imprinting
Egg PronucleusEgg Pronucleus
Sperm PronucleusSperm Pronucleus
![Page 12: Embryo Development Animal Science 434 John Parrish.](https://reader033.fdocuments.net/reader033/viewer/2022042616/56649ece5503460f94bdbf87/html5/thumbnails/12.jpg)
Imprinting
Egg PronucleusEgg Pronucleus
Sperm PronucleusSperm Pronucleus
AndrogenoteAndrogenote GynogenoteGynogenote
![Page 13: Embryo Development Animal Science 434 John Parrish.](https://reader033.fdocuments.net/reader033/viewer/2022042616/56649ece5503460f94bdbf87/html5/thumbnails/13.jpg)
Imprinting
Controls
Egg PronucleusEgg Pronucleus
Sperm PronucleusSperm Pronucleus
AndrogenoteAndrogenote GynogenoteGynogenote
![Page 14: Embryo Development Animal Science 434 John Parrish.](https://reader033.fdocuments.net/reader033/viewer/2022042616/56649ece5503460f94bdbf87/html5/thumbnails/14.jpg)
ImprintingAndrogenote Gynogenote Controls
• No Inner Cell Mass• Normal Placenta• Fails during embryo
development
• Normal Fetus• Small Placenta• Fails Midpregnancy
• Normal Fetus• Normal Placenta• Normal Pregnancy
Maternal and Paternal Genomes Are Expressed Differently in the Embryo and Fetus
Maternal and Paternal Genomes Are Expressed Differently in the Embryo and Fetus
![Page 15: Embryo Development Animal Science 434 John Parrish.](https://reader033.fdocuments.net/reader033/viewer/2022042616/56649ece5503460f94bdbf87/html5/thumbnails/15.jpg)
Gene Control of Development
OocyteGrowth
LHSurge
Fertilization Cleavage
• Transciption• Translation
• Transcription• Translation• Post
-Translation
• Translation• Post-Translation
• No transcription• Translation• Post-Translation
Maternal Gene ControlMaternal Gene Control
EmbryonicGene
Control
EmbryonicGene
Control
![Page 16: Embryo Development Animal Science 434 John Parrish.](https://reader033.fdocuments.net/reader033/viewer/2022042616/56649ece5503460f94bdbf87/html5/thumbnails/16.jpg)
Fertilization to Cleavage
Maternal Gene ControlMaternal Gene Control
![Page 17: Embryo Development Animal Science 434 John Parrish.](https://reader033.fdocuments.net/reader033/viewer/2022042616/56649ece5503460f94bdbf87/html5/thumbnails/17.jpg)
Fertilization to Cleavage
• Long Cell Cycle» Penetration to Cleavage
• Long Cell Cycle» Penetration to Cleavage
32 hour(Bovine)32 hour(Bovine)
![Page 18: Embryo Development Animal Science 434 John Parrish.](https://reader033.fdocuments.net/reader033/viewer/2022042616/56649ece5503460f94bdbf87/html5/thumbnails/18.jpg)
Precompaction Cleavage
• Cell size decreases
• Cell cycle
• Embryonic gene control
• Asynchrony of cell divisions
•Movement into Uterus
• Early pregnancy factor
• Cell size decreases
• Cell cycle
• Embryonic gene control
• Asynchrony of cell divisions
•Movement into Uterus
• Early pregnancy factor
![Page 19: Embryo Development Animal Science 434 John Parrish.](https://reader033.fdocuments.net/reader033/viewer/2022042616/56649ece5503460f94bdbf87/html5/thumbnails/19.jpg)
Precompaction Cleavage
• Cell size decreases
• Cell cycle
• Asynchrony of cell divisions
• Embryonic gene control
•Movement into Uterus
• Early pregnancy factor
• Cell size decreases
• Cell cycle
• Asynchrony of cell divisions
• Embryonic gene control
•Movement into Uterus
• Early pregnancy factor
![Page 20: Embryo Development Animal Science 434 John Parrish.](https://reader033.fdocuments.net/reader033/viewer/2022042616/56649ece5503460f94bdbf87/html5/thumbnails/20.jpg)
Precompaction Cleavage
• Cell size decreases
• Cell cycle
• Embryonic gene control
• Asynchrony of cell divisions
•Movement into Uterus
• Early pregnancy factor
• Cell size decreases
• Cell cycle
• Embryonic gene control
• Asynchrony of cell divisions
•Movement into Uterus
• Early pregnancy factor
13 hours13 hours
15 hours15 hours
30 hours30 hours
32 hours32 hours
![Page 21: Embryo Development Animal Science 434 John Parrish.](https://reader033.fdocuments.net/reader033/viewer/2022042616/56649ece5503460f94bdbf87/html5/thumbnails/21.jpg)
G1SG2 + M
Cell Cycle Lengths
16 hr16 hr
8 hr8 hr
8 hr8 hr8 hr8 hr
2 hr2 hr
<1 hr<1 hr
Total = 32 hours Total = 13 hours
1st Cell Cycle(zygote 2 cell)
2nd Cell Cycle(2 cell 4 cell)
![Page 22: Embryo Development Animal Science 434 John Parrish.](https://reader033.fdocuments.net/reader033/viewer/2022042616/56649ece5503460f94bdbf87/html5/thumbnails/22.jpg)
Precompaction Cleavage
• Cell size decreases
• Cell cycle
• Embryonic gene control
• Asynchrony of cell divisions
•Movement into Uterus
• Early pregnancy factor
• Cell size decreases
• Cell cycle
• Embryonic gene control
• Asynchrony of cell divisions
•Movement into Uterus
• Early pregnancy factor
13 hours13 hours
15 hours15 hours
30 hours30 hours
32 hours32 hoursShort G1 and G2Short G1 and G2
Short G1 and G2Short G1 and G2
![Page 23: Embryo Development Animal Science 434 John Parrish.](https://reader033.fdocuments.net/reader033/viewer/2022042616/56649ece5503460f94bdbf87/html5/thumbnails/23.jpg)
Precompaction Cleavage
• Cell size decreases
• Cell cycle
• Asynchrony of cell divisions
• Embryonic gene control
•Movement into Uterus
• Early pregnancy factor
• Cell size decreases
• Cell cycle
• Asynchrony of cell divisions
• Embryonic gene control
•Movement into Uterus
• Early pregnancy factor
Faster dividingblastomeres go
to center of embryo
Faster dividingblastomeres go
to center of embryo
![Page 24: Embryo Development Animal Science 434 John Parrish.](https://reader033.fdocuments.net/reader033/viewer/2022042616/56649ece5503460f94bdbf87/html5/thumbnails/24.jpg)
Asynchronous Cleavage - Inside Outside Theory
If a marked blastomereis placed into the interior of a 8-cell embryo, it and its progeny become part of the ICM.
If a marked blastomere is placed on the outside of a 8-cell embryo, it and its progeny become part of the trophectoderm.
TrophectodermTrophectoderm
Inner Cell MassInner Cell Mass
![Page 25: Embryo Development Animal Science 434 John Parrish.](https://reader033.fdocuments.net/reader033/viewer/2022042616/56649ece5503460f94bdbf87/html5/thumbnails/25.jpg)
Asynchronous Cleavage Use
• Create embryos from different species»Placenta from one species• Host mother
»Embryo from some other species• Donor mother
![Page 26: Embryo Development Animal Science 434 John Parrish.](https://reader033.fdocuments.net/reader033/viewer/2022042616/56649ece5503460f94bdbf87/html5/thumbnails/26.jpg)
Precompaction Cleavage
• Cell size decreases
• Cell cycle
• Asynchrony of cell divisions
• Embryonic gene control
•Movement into Uterus
• Early pregnancy factor
• Cell size decreases
• Cell cycle
• Asynchrony of cell divisions
• Embryonic gene control
•Movement into Uterus
• Early pregnancy factor
![Page 27: Embryo Development Animal Science 434 John Parrish.](https://reader033.fdocuments.net/reader033/viewer/2022042616/56649ece5503460f94bdbf87/html5/thumbnails/27.jpg)
Gene Control of Development
OocyteGrowth
LHSurge
Fertilization Cleavage
• Transciption• Translation
• Transcription• Translation• Post
-Translation
• Translation• Post-Translation
• No transcription• Translation• Post-Translation
Maternal Gene ControlMaternal Gene Control
EmbryonicGene
Control
EmbryonicGene
Control
![Page 28: Embryo Development Animal Science 434 John Parrish.](https://reader033.fdocuments.net/reader033/viewer/2022042616/56649ece5503460f94bdbf87/html5/thumbnails/28.jpg)
Transition from Maternal to Embryonic Gene Control
In vitro blocks to development often occur here!!!!!
In vitro blocks to development often occur here!!!!!
Transcription of the embryonic genome
First begins Development is dependent on
Species
Mouse 1 cell 2 cell
Rabbit 2 cell 8 cell
Pig 4 cell 8 cell
Cattle 4 cell 8-16 cell
Sheep 8 cell 16 cell
Human 4 cell 8 cell
![Page 29: Embryo Development Animal Science 434 John Parrish.](https://reader033.fdocuments.net/reader033/viewer/2022042616/56649ece5503460f94bdbf87/html5/thumbnails/29.jpg)
Precompaction Cleavage
• Cell size decreases
• Cell cycle
• Asynchrony of cell divisions
• Embryonic gene control
•Movement into Uterus
• Early pregnancy factor
• Cell size decreases
• Cell cycle
• Asynchrony of cell divisions
• Embryonic gene control
•Movement into Uterus
• Early pregnancy factor
13 hours13 hours
15 hours15 hours
30 hours30 hours
32 hours32 hours
Cell Cycle Length Increases
Cell Cycle Length Increases
Embryo runs out of key factors coded for
by maternal mRNA
Embryo runs out of key factors coded for
by maternal mRNAPause in G1Pause in G1
![Page 30: Embryo Development Animal Science 434 John Parrish.](https://reader033.fdocuments.net/reader033/viewer/2022042616/56649ece5503460f94bdbf87/html5/thumbnails/30.jpg)
Precompaction Cleavage
• Cell size decreases
• Cell cycle
• Asynchrony of cell divisions
• Embryonic gene control
•Movement into Uterus
• Early pregnancy factor
• Cell size decreases
• Cell cycle
• Asynchrony of cell divisions
• Embryonic gene control
•Movement into Uterus
• Early pregnancy factor
![Page 31: Embryo Development Animal Science 434 John Parrish.](https://reader033.fdocuments.net/reader033/viewer/2022042616/56649ece5503460f94bdbf87/html5/thumbnails/31.jpg)
Movement into the Uterus
< 8 cell< 8 cell > 8 cell> 8 cell
AmpullaAmpulla
IsthmusIsthmus
Uterine HornUterine Horn
•Occurs around day 4
•Cause
» Change in estrogen progesterone
![Page 32: Embryo Development Animal Science 434 John Parrish.](https://reader033.fdocuments.net/reader033/viewer/2022042616/56649ece5503460f94bdbf87/html5/thumbnails/32.jpg)
Precompaction Cleavage
• Cell size decreases
• Cell cycle
• Asynchrony of cell divisions
• Embryonic gene control
•Movement into Uterus
• Early pregnancy factor
• Cell size decreases
• Cell cycle
• Asynchrony of cell divisions
• Embryonic gene control
•Movement into Uterus
• Early pregnancy factor
![Page 33: Embryo Development Animal Science 434 John Parrish.](https://reader033.fdocuments.net/reader033/viewer/2022042616/56649ece5503460f94bdbf87/html5/thumbnails/33.jpg)
Early Pregnancy Factor
• Found at 24 - 72 hours after fertilization»Mice, hamster, sheep, cattle, swine, human
• Seen only in viable pregnancy»More recent experience in cattle may not
agree with this
• Function»Sensitize the uterus to implantation
»Basis for early pregnancy kit in cattle
![Page 34: Embryo Development Animal Science 434 John Parrish.](https://reader033.fdocuments.net/reader033/viewer/2022042616/56649ece5503460f94bdbf87/html5/thumbnails/34.jpg)
Morula to Blastocyst
• Polarization• Compaction• Polarization• Compaction
![Page 35: Embryo Development Animal Science 434 John Parrish.](https://reader033.fdocuments.net/reader033/viewer/2022042616/56649ece5503460f94bdbf87/html5/thumbnails/35.jpg)
PolarizationPolar BlastomeresPolar Blastomeres
Non-polar BlastomeresNon-polar BlastomeresMicrovilli
![Page 36: Embryo Development Animal Science 434 John Parrish.](https://reader033.fdocuments.net/reader033/viewer/2022042616/56649ece5503460f94bdbf87/html5/thumbnails/36.jpg)
Polarization (cont.)
Tight Junctions
Gap Junctions
![Page 37: Embryo Development Animal Science 434 John Parrish.](https://reader033.fdocuments.net/reader033/viewer/2022042616/56649ece5503460f94bdbf87/html5/thumbnails/37.jpg)
Cell LinagePolar Cells Non-polar Cells
2 polar cells 1 polar1 non-polar
2 non-polar
![Page 38: Embryo Development Animal Science 434 John Parrish.](https://reader033.fdocuments.net/reader033/viewer/2022042616/56649ece5503460f94bdbf87/html5/thumbnails/38.jpg)
Compaction• Occurs at fixed time after
fertilization
• Membranes are very close and begin to flatten. Resulting in loss of the round cell outlines.
• Differentiational event
• Genome controlled and involves microtubules and microfilaments.
• Occurs at fixed time after fertilization
• Membranes are very close and begin to flatten. Resulting in loss of the round cell outlines.
• Differentiational event
• Genome controlled and involves microtubules and microfilaments.
![Page 39: Embryo Development Animal Science 434 John Parrish.](https://reader033.fdocuments.net/reader033/viewer/2022042616/56649ece5503460f94bdbf87/html5/thumbnails/39.jpg)
Blastocyst Formation and Hatching
• Blastocoel formation
• Hatching
• Blastocoel formation
• Hatching
![Page 40: Embryo Development Animal Science 434 John Parrish.](https://reader033.fdocuments.net/reader033/viewer/2022042616/56649ece5503460f94bdbf87/html5/thumbnails/40.jpg)
Blastocoel Formation
Tight JunctionsTight Junctions
Gap JunctionsGap Junctions
Na+Na+
H2OH2O
Morula
![Page 41: Embryo Development Animal Science 434 John Parrish.](https://reader033.fdocuments.net/reader033/viewer/2022042616/56649ece5503460f94bdbf87/html5/thumbnails/41.jpg)
Blastocoel Formation
Tight JunctionsTight Junctions
Gap JunctionsGap Junctions
Na+Na+
H2OH2O
Morula
![Page 42: Embryo Development Animal Science 434 John Parrish.](https://reader033.fdocuments.net/reader033/viewer/2022042616/56649ece5503460f94bdbf87/html5/thumbnails/42.jpg)
Morula
Blastocoel Formation
Tight JunctionsTight Junctions
Gap JunctionsGap Junctions
Na+Na+
H2OH2O
Blastocoel
EarlyBlastocyst
![Page 43: Embryo Development Animal Science 434 John Parrish.](https://reader033.fdocuments.net/reader033/viewer/2022042616/56649ece5503460f94bdbf87/html5/thumbnails/43.jpg)
Blastocyst Formation and Hatching• Blastocoel
formation• Hatching
• Blastocoel formation
• Hatching
Na+Na+
H2OH2O
EarlyBlastocyst
EarlyBlastocyst
BlastocystBlastocyst
ExpandedBlastocystExpandedBlastocyst
Inner CellMass
Inner CellMass
TrophectodermTrophectoderm
Blastocoel formation • not dependent on:»Cell number»Cell division
• Embryonic genome expression required
Blastocoel formation • not dependent on:»Cell number»Cell division
• Embryonic genome expression required
![Page 44: Embryo Development Animal Science 434 John Parrish.](https://reader033.fdocuments.net/reader033/viewer/2022042616/56649ece5503460f94bdbf87/html5/thumbnails/44.jpg)
Blastocyst Formation and Hatching
BlastocystBlastocyst
ExpandedBlastocystExpandedBlastocyst
HatchingBlastocystHatching
Blastocyst
• Enzymatic digestion of zona»Plasminogen and plasminogen activator made by
embryo»Softening of zona by uterine enzymes
• Increase in size of blastocyst due to water pumping»Most important
• Day 9 - 11 in cattle, 6 in swine, and day 7 - 8 in horses or sheep
• Enzymatic digestion of zona»Plasminogen and plasminogen activator made by
embryo»Softening of zona by uterine enzymes
• Increase in size of blastocyst due to water pumping»Most important
• Day 9 - 11 in cattle, 6 in swine, and day 7 - 8 in horses or sheep
• Blastocoel formation
• Hatching
• Blastocoel formation
• HatchingEarly
BlastocystEarly
Blastocyst
![Page 45: Embryo Development Animal Science 434 John Parrish.](https://reader033.fdocuments.net/reader033/viewer/2022042616/56649ece5503460f94bdbf87/html5/thumbnails/45.jpg)
Formation of Twins
• Dizygotic»Not identical
»Double ovulation
• Monozygotic» Identical
»Several potential mechanisms
![Page 46: Embryo Development Animal Science 434 John Parrish.](https://reader033.fdocuments.net/reader033/viewer/2022042616/56649ece5503460f94bdbf87/html5/thumbnails/46.jpg)
Formation of Monozygotic Twins
SiameseTwins