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Reproductive Biotech. Superovulation b treatment of the female with hormones so that more eggs are ovulated than normal.

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Presentation on theme: "Reproductive Biotech. Superovulation b treatment of the female with hormones so that more eggs are ovulated than normal."— Presentation transcript:

1 Reproductive Biotech

2 Superovulation b treatment of the female with hormones so that more eggs are ovulated than normal

3 Superovulation b alter normal level of FSH b Follicle Stimulating Hormone b Typical results are ovulation of 10 or more eggs

4 Superovulation b recipient animals must be closely synchronized with the donor cow. b Must be at the same stage in their heat cycle

5 EmbryoTransfer b provides opportunity to introduce genetic material into populations of livestock while greatly reducing risk of transmission of diseases

6 ET Process b super ovulate donor cow b synchronize recipients b breed donor cow (A.I.) when in heat

7 ET Process b flush - remove fertilized eggs from donor before 7 days gestation b plant embryo in the recipient animal

8 Transfer to recip. b Non surgical b common b deposit embryo in uterus through cervix with AI straw and gun

9 non surgical b usually 70-80% success rate

10 Surgical b incision in recip through flank b tip of uterine horn is exposed b cut open and embryo is deposited

11 Surgical b recip is sewn shut b less than 60-65% success rate.

12 ET b now allows for shipping of 500 registered holsteins in four sealed flasks in one seat on an airplane

13 Splitting Embryos b remove embryo from cow 7 days after conception b collect unfertilized egg and cut into zona pellucida

14 Splitting Embryos b remove contents of unfertilized egg leaving the zona intact b similarly, cut into zona around embryo

15 Splitting Embryos b divide cells in embryo in half using a micro surgical blade b remove 1/2 of the cells and transfer them into empty zona

16 Splitting Embryos b seal zona with microjolt b each 1/2 put into recipient animals

17 Cloning b 6 days after conception, 32 cell embryo is removed from donor cow b recipient egg cell is taken from a slaughterhouse

18 Cloning b recipient cells DNA is removed b one of the 32 cells is removed from the embryo

19 Cloning b the single cell is inserted into recipient egg b recipient cell is given a microjolt - fuses grafted DNA to plasma membrane

20 Cloning b desired embryo will replace cells that are removed providing a continuing supply of DNA to be inserted into more recipient cells

21 Cloning b resulting offspring are cloned identical siblings

22 Sexing Embryos b usually done by determining if embryo is a male b males have Y chromosome b H-Y antigen can be detected in male cells

23 Detection of Y b break open cells and stain chromosomes to identify presence of Y chromosome b Karyotyping b must examine at least 10 cells

24 Detection of Y b 70% accurate b use Y specific probe for ID b Y specific probe attaches to Y chromosome

25 Detection of Y b can be detected by radioactivity or special light b 85% accurate

26 H-Y Antigen b make an antibody by injecting H-Y antigen into mice b attach dye onto the antibody for easy detection of male embryo

27 H-Y Antigen b add antibody to embryo and if embryo is male it will glow b if it is female it will remain dark

28 Advantages b does not kill cell b no damage to embryo b fast - can be few hours or less than one hour old

29 Disadvantages b need high skilled technician b 80% accurate

30 Freezing Embryos b cooling embryos -5C or 40 F b can be stored several days b freezing -196 C or -320 F b must cool before freezing

31 Freezing Embryos b slowly cooled to -25C at a rate of.5C per minute and then plunged into liquid Nitrogen

32 Freezing b cryoprotectants are used to lower the freezing point so removal of water can be increased

33 Freezing b Cryoprotectant used in cattle - glycerol b also help prevent cell membrane from becoming brittle b dilutes salt in cell

34 Thawing b 500 C per minute b complete is about 20 seconds b glycerol is removed and embryo is placed in successive solutions

35 Thawing b glycerol is removed and embryo is placed in successive solutions to re hydrate

36 Thawing b if done too slowly embryo will burst because large ice crystals will form b 70-80% success rate

37 Animals b Genetic Transformation b two tools b embryo micromanipultion b recombinant DNA technology

38 Genetic Trans. b Occurs when new genetic info is introduced into animals genome

39 Methods b ES - Embryonic Stem b EC - Embryonic Carcinoma cells

40 ES or EC b cells harboring the foreign gene are incorporated into blastocyst resulting in a mosaic animal

41 EC b potential for tumor formation

42 Retrovirus infection b retro. Carrying desired gene is used to transformhost b close to 100% efficient

43 Microinjection b of several hundred copies of DNA are injected into male pronucleus of one or two cell embryos

44 Microinjection b inefficient b mice % are born b only 25% express new trait

45 Screening b is it transgenic? b Incorporation of gene b expression of gene b germline incorporation

46 Agricultural Use b rabbit b sheep b pig b cow

47 The End !! :)


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