Don’t let this happen to you!!

1. Don’t let this happen to you!!

2. Male or Female? The gender of a baby is determined by genes on chromosomes. There are 23 pairs of chromosomes in each of our cells. One of pair of chromosomes are called sex chromosomes.

3. The sex chromosomes determine whether a person is male or female. The sex chromosomes are the only pair of chromosomes that do not always match.

4. X or Y Females • The two sex chromosomes • match – XX • Since both of a female’s sex • chromosomes are X, all eggs • carry one X chromosome. • Males • The two sex chromosomes • do not match – XY • Males have two different sex • chromosomes, so sperm cells • will either carry an X or a Y chromosome

5. Sex Linked Disorders Some human traits occur more often in one gender than the other. Sex-Linked Genes: Genes on the X and Y chromosomes, whose alleles are passed from parent to offspring on sex chromosomes

6. In females, a dominant allele on one X chromosome will mask a recessive allele on the other X chromosome. In males, there is no matching allele on the X and Y chromosome. As a result, any allele on the X chromosome will produce the trait in a male who inherits it.

7. Why Males??? • Because males have only one • X chromosome, males are • more likely than females to • have a sex-linked trait that is • controlled by a recessive • allele. • Example of sex-linked trait • controlled by a recessive • allele: red-green color • Blindness affects more males than females

8. Hemophilia-prevents blood from clotting, and people with hemophilia bleed for a long time after small cuts.

9. Pedigrees Pedigree: A chart or “family tree” that tracks which members of a family have a particular trait. A diagram that show the occurrence of a genetic trait in several generations of a family.

10. Selective Breeding Selective Breeding: Breeding organisms with desired traits so that their offspring will have those traits

11. Karyotype Karyotype: A picture of all of the chromosomes in the cell. The chromosomes are arranged in pairs.

12. MUTATIONS Changes in DNA that affect genetic information Genetic Disorder: An abnormal condition that a person inherits through genes or chromosomes! Genetic disorders are caused by mutations

13. What Causes Mutations? • There are two ways in which DNA can become mutated: • Mutations can be inherited. • Parent to child • Mutations can be acquired. • Environmental damage • Mistakes when DNA is copied

14. Gene Mutations • Point Mutations – changes in one or a few nucleotides • Insertion • THE FAT CAT ATE THE RAT • THE FAT CAT XLW ATE THE RAT • Deletion • THE FAT CAT ATE THE RAT • THE FAT ATE THE RAT • Substitution THE FAT CAT ATE THE RAT THE FAT HAT ATE THE RAT

15. Insertion- a mutation when an extra base is added into the DNA strand Deletion- a mutation when a base is left out of the DNA Substitution- a mutation when the wrong base is used in the DNA strand. (most common)

16. Gene Mutations • Frameshift Mutations – shifts the reading frame of the genetic message so that the protein may not be able to perform its function. • Insertion • THE FAT CAT ATE THE RAT • THE FAT HCA TAT ETH ERA T • Deletion • THE FAT CAT ATE THE RAT • TEF ATC ATA TET GER AT H H

17. Chromosome Mutations • Changes in number and structure of entire chromosomes • Original Chromosome ABC * DEF • Deletion AC * DEF • Duplication ABBC * DEF • Inversion AED * CBF • Translocation ABC * JKL GHI * DEF

18. Carrier carrier of a genetic mutation is an individual who inherited an altered form of a gene but had no effects or symptoms of that gene change or mutation.

19. Significance of Mutations • Most are neutral • Eye color • Birth marks • Some are harmful • Sickle Cell Anemia • Down Syndrome • Some are beneficial • Sickle Cell Anemia to Malaria • Immunity to HIV

20. Chromosome Mutations • Down Syndrome • Chromosome 21 does not separate correctly. • They have 47 chromosomes in stead of 46. • Children with Down Syndrome develop slower, may have heart and stomach illnesses and vary greatly in their degree of intelligence.

21. Cystic Fibrosis Genetic disorder in which the body produces too much mucus in the lungs and intestines.-The mucus makes it hard to breathe and digest food. This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.

22. Sickle-Cell Disease • Genetic disorder that affects the production of hemoglobin in the blood. • This causes blocked blood vessels, which leads to difficulty breathing, pain and weakness

23. Sex Chromosome Abnormalities • Klinefelter’s Syndrome • XXY, XXYY, XXXY • Male • Sterility • Small testicles • Breast enlargement

24. Sex Chromosome Abnormalities • XYY Syndrome • Normal male traits • Often tall and thin • Associated with antisocial and behavioral problems

25. Sex Chromosome Mutations • Turner’s Syndrome • X • Female • sex organs don't mature at adolescence • sterility • short stature

26. Sex Chromosome Mutations • XXX • Trisomy X • Female • Little or no visible differences • tall stature • learning disabilities • limited fertility

27. Sex Chromosome Abnormalities

29. Some mutations even make it on SNL!

31. Advances in Genetics Three methods that people have used to develop organisms with desirable traits: Selective breeding Cloning Genetic Engineering

32. Selective Breeding Selective Breeding: Breeding organisms with desired traits so that their offspring will have those traits

33. Inbreeding: Crossing two individuals with similar or identical alleles – increases genetic disorders Hybridization: Breeding two genetically different individuals

34. Cloning Clone: An organism that is genetically identical to the organism from which it was produced Cloning can be done with plants and animals

35. Genetic Engineering Genetic Engineering: Genes from one organism are transferred into the DNA of another organism Used to produce medicine, improve crops, and cure genetic disorders