1. Human Intervention in Evolution

2. Advantages of Artificial Selection Specific individuals selected to contribute to next generation for: Economic reasons Aesthetic reasons

3. Reproductive Technologies Artificial insemination Multiple ovulations and embryo transfer (MOET) Sex selection through sperm sorting Oestrus synchronisation

4. Artificial Insemination Semen is collected from male and transferred to females Advantage is yield: normally in a single mating there is the potential for one female to be inseminated Via artificial insemination one ejaculate can fertilise 10 females. Semen can be snap frozen in liquid nitrogen and stored for many years

5. Artificial Insemination Advantages Can fertilize many females Can fertilize distant females Can fertilize beyond the lifespan of the male Prized male can make larger genetic contribution Disadvantages Loss of genetic diversity As one allele is favoured, alternatives are completely lost Whilst breeding for a particular trait, others may be unintentionally gained or lost

6. Artificial Insemination in plants Cover stigma Remove stamen Collect pollen from anthers Expose to stigma of many other plants

7. Artificial Insemination in plants x Rye (Secale) RR Wheat (Triticum) WW When one species is used to fertilize another, a hybrid is produced As chromosomes are non-homologous, hybrid is sterile Treatment with certain chemicals will cause doubling of chromosomes in all cells, thereby producing a fertile hybrid Sterile hybrid WR Treatment with colchicine Fertile hybrid (Triticosecale) WWRR

8. Multiple ovulations and embryo transfer (MOET) Valued females can also make a larger genetic contribution. Inject with FSH (stimulates super-ovulation) Inject with GnRH (all eggs mature simultaneously) Fertilise eggs through in-vitro fertilisation Implant eggs in to surrogate female MOET will usually increase the yield of a valued female by a factor of 7

9. Sex selection through sperm sorting Add a harmless fluorescent dye to sperm Dye attaches to DNA X chromosomes contain more DNA Sperm containing X chromosome will fluoresce more brightly Select these sperm

10. Oestrus synchronisation All females in herd are effectively “put on the pill” by being given progesterone. If all are taken of progesterone at the same time, ovulation will occur simultaneously. Makes herd easier to manage

11. Cloning Technique #1 – Embryo splitting Pryor to blastocyst formation (>32 cells), the cells of the zygote can be divided with a very fine needle and implanted in to a surrogate. Technique # 2 – Nuclear transfer Can be performed via somatic cell fusion Can be performed via fusion with a donor embryo cell

12. Somatic cell fusion Fusion with a donor embryo

13. Dolly was created via nuclear transfer (somatic cell fusion)

14. Some cloning successes CC Snuppy with the “mother” from which she was cloned Snuppy with her surrogate mother

15. The downside to cloning Many unsuccessful attempts CC (cat): 87 Snuppy (dog): 123 2nd Chance (bull): 189 Dolly (sheep): 277 This does not apply to plants as cloning occurs naturally (cuttings, runners, rhizomes) Shortening telomeres Every time a cell divides it loses some DNA from its telomeres (ends of the chromosomes) Implies that clones are born with “old” DNA Recent studies have indicated that this may not be the case Clones had loner telomeres than original

16. Transferring genes A gene transferred to bacteria is transformed eg. human insulin grown in bacterial colony A gene transferred to another species is transfected eg. Spider gene in goat allows silk to be harvested from goat’s milk Gene therapy involves the replacement of a faulty allele with a working one

17. Stem Cells The source of the stem cell will determine how far-reaching its adaptive abilities are.

18. Harvesting Stem Cells Pluripotent stem cells are taken from the inner cell mass of a blastocyst. Stem cells can be used to replace damaged or diseased cells in almost any part of the body

19. Therapeutic (non-reproductive) cloning Embryos can also be cloned from the healthy cells of a diseased patient to create stem cells of the appropriate blood and tissue type.

20. Ethical Issues Extraction of stem cells destroy what may have been a perfectly healthy embryo. Current legislation states that stem cells may only be taken from embryos deemed to be “in excess” during IVF procedures. Embryos cannot be created simply for the purpose of harvesting stem cells

21. Overcoming Infertility Infertility problems are usually 50% female, 30-40% male and 10-20% incompatibility. Solutions: Donor Sperm Legally the child belongs to the mother and her husband at the time of birth

22. Overcoming Infertility IVF (In-vitro fertilisation) Treats Low sperm count Poor swimmers Damaged fallopian tubes Hostile mucous Problems associated with implantation of egg in to uterine wall

23. In-vitro fertilisation Egg incubated with sperm in culture fluid Protective band of cells removed from around fertilized egg Embryo returned to mother’s uterus at either the 2 or 4 cell stage

24. Overcoming Infertility IVF with donor egg Surrogacy Implant IVF fertilised egg in to the womb of another female GIFT (gamete intrafallopian transfer) Sperm and eggs unable to meet can be collected and placed together in the fallopian tube Intracytoplasmic sperm injection Sperm unable to naturally penetrate egg are injected

25. In Conclusion IVF ethical issues: What happens to frozen egg, sperm or embryos after the death of one parent? On request of the family, can sperm / eggs be collected from someone after an untimely death? Chapter review questions: Ch. 16: 3-5,7,8,11