Human Intervention in Evolution

1. Human Intervention in Evolution

2. Selective Breeding • This is a form of artificial selection • Involves choosing individuals from a population that have a certain trait and breeding those individuals • This is done across several generations • Eventually the trait is seen in all of the offspring and becomes more pronounced • Used in farming, agriculture, and race horses

4. Reproductive Technology used in livestock • Artificial insemination (AI) – sperm from a selected animal is extracted and artificially introducing it into a female reproductive tract • Sex selection through sperm sorting – sperm are collected and analysed – separated into two groups – X and Y carrying sperm – uses a fluorescent dye

5. Reproductive Technology used in livestock • Multiple Ovulation Embryo Transfer (MOET) • stimulate a female to produce many eggs at once • use AI to fertilise them within the body • after 6 days the uterus is flushed to extract the embryos • these are then inserted into other females to begin gestation

6. Cloning • Cloning - creating genetically identical copies of an organism • Two methods: • Splitting embryos • Creating an embryo using IVF and using a fine needle to extract embryo cells that can divide and form new identical embryos • Somatic Cell Nuclear Transfer (SCNT) • Inserting the nucleus of a somatic cell into an ovum that has had its nucleus removed

7. Cloning

9. Gene Therapy

10. Gene Therapy • Still in development • Attempts to introduce normal copies of genes into the cells of an individual with a genetic disorder • Involves cloning the gene using a plasmid and then using a vector (carrier) to get it into the cells • Vectors include inactivated viruses and liposomes

11. Gene Therapy

12. Gene therapy for Haemophilia

13. Prenatal Gene Therapy

14. Stem Cells Blastocyst • When sperm fertilises an ovum it forms a zygote. • The single cell grows and divides. Within 5 or 6 days there are up to 120 cells. • They form into a ball called the blastocyst. • Each cell is pluripotent, capable of developing into any cell type in the human body such as heart, skin or hair.

15. Stem CellsCan make every cell type in the body.They are ‘pluripotent’

16. Therapeutic Cloning – to produce stem cells A doctor takes a sample of skin cells from the patient and isolates their DNA. A donor egg cell, emptied of its own genetic contents, is injected with the DNA from the patient. The embryo is nurtured to grow and divide into a blastocyst. Some blastocyst cells are harvested and coaxed with growth factors to mature into insulin-producing cells. Millions of insulin-producing cells are injected back into the patient. The patient's diabetes is temporarily 'reversed', with no side effects.

17. Genetic Screening • Genetic screening can be performed for a variety of reasons: • Test carrier status for a particular disorder • Test whether there is a predisposition to cancer • Pre-natal testing for expectant parents

18. Gel electrophoresis Hybridisation DNA microarrays Pedigree analysis

19. Reproductive technology • Assist in overcoming infertility • Variety of methods: • In-vitro fertilisation (IVF) – sperm and ovum extracted and allowed to fuse outside of the body Embryo inserted into the uterus at the six cell stage • Gamete Intra-fallopian Transfer (GIFT) – sperm and ovum extracted and injected into the fallopian tube of the female so fertilisation happens in the body

20. Reproductive technology Intracytoplasmic Sperm Injection – sperm and ovum extracted and the sperm is injected directly into the ovum. Embryo inserted into the uterus at six cell stage. Preventing pregnancy (contraception) also falls under the category of reproductive technology

21. IVF

22. GIFT

23. Intracytoplasmic Sperm Injection

24. Questions to complete • All Quickcheck • Biochallenge Page 652 • Chapter Review: 2, 3, 4, 5, 6, 7, 9bcd, 11, 12