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Implantation, placentation and post-implantation embryonic
development
Timing of implantation
• Marmoset 11-12 days• Rhesus 6-7 days• Human 6-7 days• Mouse 6 days
Marmoset implantation
• Implantation day—11-12 post- ovulation
Marmoset twin early implantation site
From Moore et al. 1985
A
B
Stages of placentation
Patterns of twinning
MarmosetMarmoset
7 8 9
10 11
Primitive Streak to Limb Bud Stages
Overview of Embryo StagesCarnegie System
Overview of Embryo StagesCarnegie System
11 12 13 14
Somite/Neurula to Limb Bud Stages
15 16 17 18
Timing of marmoset embryonic development
• Early limb bud stage (stage 11) GD 50– 25 days later than human
• From stage 11 to 23 (completion of organogenesis) – 30 days duration for both marmoset and
human
Time course for embryonic development
Total time required to complete embryonic development
• Marmoset 80 days (due to 50 days to limb bud stage)• Rhesus 47 days• Baboon 47 days• Human 58 days
Time required for fetal development(from the end of embryonic development
till birth)
• Marmoset 64 days • Rhesus 118 days• Baboon 133 days• Human 222 days
Total pregnancy duration
• Marmoset 144 days • Rhesus 165 days• Baboon 180 days• Human 280 days
Age of sexual maturity
• Marmoset 1.5 years • Rhesus 4.5 years• Baboon 7-10 years• Human 14-16 years
Critical embryonic development stages: formation of the blood system
13
Formation and migration of the primordial germ cells
Stage 14Stage 11
Development of the gonads
13
16
Fusion of placentain marmoset
• Unique feature of Marmoset and Tamarinplacentation is fusion and sharing of fetal circulation between litter mates
• Fusion of the placenta (chorionic membranes)starts soon after implantation and is completed before organogenesis
• Shared placental circulation results in hemopoietic and bone marrow chimerism
Hearn 1983
At birth
Consequences of sharing fetal circulation
• Fusion of placenta results in blood chimerism and chimerism in other organs.
Are the gametes also chimeric?
Germ line chimerism
This means sharing the cells among 3 or more individuals instead of only 2.
What could be the consequences for the individual?
An additional complication for chimerism – increase in litter size
Possible reason for increased litter size
DPZ CENP Brazil
Can we influence litter size and health with different captive management?
• High weight animals tend to have larger litters
• Can this be a cause of later health problems?– partially induced by autoimmune disease due to
mixing of cells from 3 or more individuals.
• Could a change in captive management bring litter size under control and improve health of the animals?