GENETIC DISORDERS

1. GENETIC DISORDERS

2. Two Types of Mutations • Gene mutation: single gene defective • Insertion • Substitution • Deletion • Chromosomal mutation: missing or extra chromosome • Monosomy • Trisomy • Deletion • Either can involve autosomes (chromosomes 1-22) or sex chromosomes

3. Autosomal Disorders • Disorders involving the 22 pairs of chromosomes that are NOT sex chromosomes (X,Y). • Can result from • Gene mutation: defective gene on autosome • Chromosomal mutation: loss or gain of autosome

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5. Autosomal DisordersGene Mutations 1- Cystic Fibrosis • Recessive disorder • Mutated geneon chromosome 17. • Characterized by excessive, THICK secretion of the mucus in the body.

7. Autosomal DisordersGene Mutations 2- Huntington Disease • Dominant disorder • Mutated gene on chromosome 4 is responsible. • Causes degeneration of neurons producing dementia, and random jerking movements.

8. Autosomal DisordersGene Mutations 3- Phenylketonuria (PKU) • Recessive disorder • Mutated geneon chromosome 12is responsible 4- Sickle-Cell Anemia • 1 of 12 U.S. African Americans • Recessive disorder • Mutated geneon chromosome 11

9. Autosomal DisordersGene Mutations 5- Tay-sachs Disease • Recessive disorder • European Jewish ancestry. • Mutated geneon chromosome 15 Tay-sachs—One Wrong Letter

10. Autosomal DisordersChromosomal Mutations Down Syndrome • 1 in 1,000 live births. • Extra Chromosome 21 • Risk increases with mom’s age • Pregnancies of women over age 35 accounts for 20% of Down syndrome births

12. Sex-Linked Disorders • Involve the sex chromosomes • Recessive gene on the X chromosome is more likely to be expressed in males • ***Y chromosome has no 2nd allele that might counteract the gene on the X chromosome!

14. Sex-Linked DisordersGene Mutations 1- Color Blindness • X-linked recessive disorder • Gene mutation on X chromosome • 1 of 10 males 2- Hemophilia • X-linked recessive disorder • Gene mutation on X chromosome. • 1 of 5,000 males • Interfere with normal blood clotting

15. Sex-Linked DisordersChromosomal Mutations 1- Klinefelter Syndrome (XXY) • 1 of 1,000 males. • Extra X chromosome

17. Sex-linked DisordersChromosomal Mutations 2- Turner’s Syndrome (XO) • 1 of 10,000 females • One of X chromosomes is either missing or inactive • Have immature female appearance and lack internal reproductive organs.

19. GENETIC DISORDERS Autosomal Disorders Chromosomes 1-22 Sex-Linked Disorders Sex Chromosomes X and Y Gene Mutations 1 gene mutated on chromosomes 1-22 Chromosomal Mutations Extra or missing chromosome 1-22 Gene Mutations 1 gene mutated on X chromosome Chromosomal Mutations Extra or missing Sex chromosome EXAMPLES?

20. How Do We Know About All of Our Genes? • Human Genome Project • Began in 1990 • Goals: • Determine complete sequence of the 3 billion DNA bases in human DNA • Identify all human genes for further biological study

21. The Unknown • Gene number, exact locations and functions • Gene regulation • DNA sequence organization • Chromosomal structure and organization

22. Ethical, Legal and Social Issues • Fears • Genetic information used to harm or discriminate • Deny access to health insurance • Deny employment • Deny education • Deny loans? • Cloning? • DNA Databases

23. Cloning • Creating many genetically identical cells from one cell. • Creation of genetically identical organisms

24. Biotechnology Dolly and surrogate Mom Embryonic stem cells and gene therapy Genetically modified rice.

25. Why Clone Animals? Five genetically identical cloned pigs. To answer questions of basic Biology For pharmaceutical production. For herd improvement. To satisfy our desires (e.g. pet cloning).

26. Is Animal Cloning Ethical? The first cloned horse and her surrogate mother/genetic twin. As with many important questions, the answer is beyond the scope of science.