1. Competency Goal # 3 The learner will develop an understanding of the continuity of life and the changes of organisms over time. Part 4

2. 1.Why should close relatives not mate?  Most human disorders are inherited as rare recessive alleles. Mating with close relatives increases the chances that a recessive disorder will be inherited. 2. If a trait is sex-linked, where is the gene located?  On the 23 rd chromosome; most on X 3. Name sex-linked traits in humans.  Red-green color blindness  Hemophilia

3. 4.Show a Punnett square of a carrier female and normal male. 5.What is a pedigree?  A graphic representation of genetic inheritance

4. 6.Who determines the sex of a child?  It is the male gamete that determines the sex of the offspring.

5. 7.What is meant by a polygenic trait?  A trait that is controlled by two or more genes.  Skin color, and height are examples 8.What important contribution did Charles Drew make?  Improved storage for blood storage and increasing the blood blank

6. 9. What is a karyotype?  Chart of chromosome pictures enlarged and arranged in pairs 10. What can you tell by looking at the chromosomes in a karyotype?  Valuable in identifying unusual chromosome numbers in cells

7. 11.Explain how amniocentesis can be used to screen for genetic disorders.  A small amount of amniotic fluid, which contains fetal tissues, is extracted and the fetal DNA is examined 12.How can gel electrophoresis be useful:  Law enforcement: Matching DNA samples from crime scenes; fingerprinting  Medicine: Research in developing cures for diseases

8. 13.How can human insulin be produced using DNA technology?  The human gene for insulin is inserted into a bacterial plasmid by genetic engineering techniques. Recombinant bacteria produce large quantities of insulin. 14. What is a transgenic organism?  A plant or animals that contain functional recombinant DNA from an organism of a different genus  Example: high protein corn, better tasting, last longer, resistance to pest and disease, increased vitamins

9. 15. What is cloning?  The process of making a genetically identical copy 16. What are the advantages and disadvantages of cloning?  Advantage: Rancher and dairy farmers could clone particularly productive, healthy animals to increase yield; medical research  Disadvantage: Ethical issues