Current Genetic Topics

1. Current Genetic Topics Disorders, Cloning, Gene Therapy

2. Atypical meiosis • If something wrong happens during meiosis, this can impact many things. • If there is an error in the chromosomes, ALL the cells will be affected.

3. Nondisjunction • Nondisjunction: the failure to separate. • When two homologous chromosomes move to the same pole during meiosis instead of moving to opposite poles. • One of the resulting cells ends up with a chromosome missing, while the other has an extra. • These cells will not work as they should.

5. Nondisjunction • When a fertilized egg with an abnormal number of chromosomes divides, each cell in the body will also have an abnormal amount of chromosomes. • In most cases, the zygote will die. • However, sometimes a person with nondisjunction disorder is born.

6. Down Syndrome • An extra chromosome for chromosome pair 21 – too much genetic information.

7. Turner Syndrome • Occurs when sex chromosomes undergo nondisjunction in the male or the female parent. • Produces a female with one X chromosome instead of two. • Do not mature sexually and are often are small in stature.

8. Klinefelter Syndrome • Nondisjunction in egg or sperm cell • Inherits two X chromosomes and one Y chromosome • The resulting baby will be a male, but during puberty will begin to develop high levels of female sex hormones • These males are sterile.

9. Genetic Screening • Genetic screening is a process by which a doctor draws amniotic fluid from the sac that surrounds the fetus. • This fluid contains cells which doctors can now screen and determine whether the baby will be born with a genetic disorder. • https://www.youtube.com/watch?v=8eR4XdJSmqc

10. Genetic Screening in Canada • http://healthycanadians.gc.ca/health-sante/pregnancy-grossesse/gen-test-eng.php

11. Genetic Screening • Flip to page 225 and break into groups of 2. • Read through the points and counterpoints and then work through the “What do you think” section. • Eliminate the 3rd point. • Discuss these points as a class.

12. Cloning What comes to mind?

13. Cloning • Cloning is a natural process that happens often in nature • Examples? • Binary Fission – the mother cell splits into two identical daughter cells • Budding, vegetative reproduction, etc

14. Cloning • Cloning is the process of forming identical offspring from a single cell or tissue. • ASEXUAL REPRODUCTION

15. Cloning a Plant • Frederick Stewart had great success taking a single carrot cell and growing it into a plant. • Isolated a portion from the root tip of the carrot • The key to success in cloning plants is to slow down the specialization process of the cells • Ex. Leaf cells, root cells, stem cells

16. Cloning Animals • Robert Briggs and Thomas King successfully cloned a frog. • Extracted nucleus from an unfertilized egg cell • Next, a nucleus was extracted from a frog embryo in early development • This nucleus was inserted into the unfertilized egg cell.

17. Mammal Cloning • See diagram on page 196

18. Dolly

19. Dolly • http://www.nytimes.com/2013/10/14/booming/the-clone-named-dolly.html?_r=0 • Dolly was different because the clone originated from taking cells from an FULLY DEVELOPED SHEEP. • See diagram on page 197

20. Stem Cell • Stem cells are very special, powerful cells found in both humans and non-human animals. They have been called the centrepieces of regenerative medicine – medicine that involves growing new cells, tissues and organs to replace or repair those damaged by injury, disease or aging. • Source: • http://www.stemcellnetwork.ca/index.php?page=what-are-stem-cells

21. Gene Therapy • Gene therapy is an experimental solution for treating disease by changing the patient's genetic material. • Most often, gene therapy works by introducing a healthy copy of a defective gene into a person’s cells. • http://www.bbc.com/news/health-26473802

22. Discussion • Think-pair-share • Has science gone too far? • Should we continue with cloning, gmos, genetic screening? • Should governments be allowed to dictate whether this science is