A History of Embryology

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A History of Embryology

• 1890-2002

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• 1890 1st successful ET in rabbits
• 1951 1st successful ET in cattle
• 1970 commercial ET in cattle
• 1972 1st successful cloning experiment
• 1972 1st frozen ET in mice
• 1973 1st frozen ET in cattle (Frosty)
• 1980 freezing commercially available
• successful embryo splitting
• 1st cloning by nuclear transfer

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• 1981 first bovine IVF
• 1986 cloned lambs via nuclear transfer
• 1987 1st calves cloned
• 1993 commercial IVF
• 1994 commercial quick thaw
• 1997 Dolly made via NT from adult cell
• 1998 cattle cloned from adult cell
• 2001 first ever applied embryology class
  at Cal Poly State University!

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Review of female reproduction

• Estrous cycle reproductive cyclicity
• Estrus (heat) period of sexual receptivity
• Estrous adjective
• Estrus noun

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Typical cycle lengths

• Human 28 days
• Horses 22 days
• Cattle 21 days
• Sheep 18 days
• Mice 4 days

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Two estrous cycle phases

• Follicular phase growth and maturation of
  follicles
• Luteal phase presence of CL on ovary
• See figure 8.4 and 9.1

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• Ovarian hormones
• Estrogen, progesterone, inhibin
• Anterior pituitary hormones
• LH and FSH
• Hypothalamus hormones
• GnRH

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GnRHLH/FSH E2

I Follicular Growth
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• Inhibin inhibits FSH
• PGF2alpha lyses CL
• hCG human chorionic gonadotropin
• LH-like activity
• PMSG pregnant mare serum gonadotropin
• FSH-like activity

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In the Ovary

• Primary follicle
• Secondary follicle
• Tertiary follicle
• Graafian follicle

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In the FolliclePrimary oocyteSecondary oocyte