1 / 55

Chapter 14

Chapter 14. - The Human Genome. 14-1 Human Heredity. The children in this family have some traits that are similar to their mother’s and some that are similar to their father’s. Can you predict chin shape? Procedure

kirish
Download Presentation

Chapter 14

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chapter 14 - The Human Genome

  2. 14-1 Human Heredity • The children in this family have some traits that are similar to their mother’s and some that are similar to their father’s.

  3. Can you predict chin shape? • Procedure • Two parents with cleft chins, both heterozygous for cleft chin (Cc), have three children with cleft chins. The parents are sure that their fourth child will not have a cleft chin. Draw a Punnett square to see if this is possible. • Determine the probability that the fourth child will have a cleft chin. _________

  4. Human Heredity • Human Chromosomes • Make us who we are. • This is the genetic information (DNA) which is inside the human cell.

  5. To look at these chromosomes, biologists, photograph cells in mitosis. • Mitosis is when the cell nucleus divides and the chromosomes are easier to see. • Biologists then take these photographs and group them together in pairs. • This picture of chromosomes arranged in this way is called a karyotype

  6. Karyotype

  7. The human body contains 46 chromosomes • 23 (sperm) • 23 (egg) • Together this forms a diploidzygote • 46 total chromosomes

  8. Sex Chromosomes and Autosomes • Sex chromosomes • Only 2 of the 46 • Determine if someone is male or female • Female: XX • Male: XY • Autosomes • Remaining 44 chromosomes

  9. Human Traits • Human traits are inherited • Gregor Mendel • Pedigree chart • A pedigree shows a relationship within a family • A pedigree chart follows one specific trait in a family

  10. Cleopatra’s Pedigree Chart

  11. Russian Royal Family Pedigree Chart

  12. Polygenic • Some traits are actually polygenic • Controlled by two or more genes • Shape of your eyes • Shape of your ears • Eye color

  13. Other Trait Influences • Environment • Nutrition • Exercise • Your parents might both be 6 feet tall, but if they don’t feed you, you are unlikely to grow to be 6 feet tall.

  14. Human Genes • Our complete set of genetic information is our genome • 30,000 genes • Blood Group Genes: • Knowing a person’s blood group is critical because using a wrong blood type could be life threatening • Rh • ABO • Are two genes that are part of your blood type

  15. Rh • Rhesus Monkey” • 2 alleles that determine blood type • Rh+ is dominant & Rh- is recessive • A person with 2 positive alleles is Rh+ • A person with a positive and a negative allele is RH+ • A person with 2 negative alleles is Rh-

  16. ABO • There are 3 alleles that determine blood type • IA,IB and i • Two of these alleles are codominant and one is recessive. • Blood type is dependant upon what the antigens are on the surface of the red blood cells • Type A blood: lAlA, or IAi • Type B blood: IBIBor IBi • Type AB blood: IAIB • Type O blood: ii

  17. Based on what you know of blood types; which one of Mr. & Mrs. Lopez’s four kids must have been adopted? _____________

  18. Recessive Alleles • Studying genetic disorders have helped us understand how human genes work • Many of these disorders are caused by recessive alleles

  19. Phenylketonuria (PKU) • People with this disorder lack the enzyme needed to break down Phenylalanine • Causes: • A build-up of phenylalanine in tissues • Mental retardation • Can be controlled by a special diet • All babies in US are tested for this at birth

  20. Tay-Sachs Disease • Nervous system breakdown • Infant death

  21. Albinism • Lack of pigment in skin, hair, and eyes

  22. Cystic FibrosisGalactosemia • Inability to digest the sugar galactose. • Causes mental retardation, eye and liver damage • Excess mucus in lungs, digestive tract, and liver • Susceptibility to infections • Death in early adulthood if not treated

  23. Cystic Fibrosis

  24. Dominant Alleles • Not all genetic disorders are caused by recessive alleles • If you have a dominant allele for a genetic disorder, it will be expressed even if you also have a normal recessive allele • Achondroplasia • Huntington’s disease • Hypercholesterolemia

  25. Achondroplasia • Dwarfism

  26. Huntington’s Disease • Mental deterioration and uncontrollable movements Hypercholesterolemia • Excess cholesterol in blood • Heart disease

  27. Gene Expression • In certain diseases, a small change in the DNA of a single gene affects the structure of a protein, causing a serious genetic disorder • Cystic fibrosis • Sickle cell anemia

  28. Sickle Cell Anemia • Abnormal hemoglobin produced because of a single amino acid change in the hemoglobin protein • Causes the RBC’s to deform which causes clogging in the capillaries

  29. Sickle Cell Anemia

  30. 14-2 Human Chromosomes Sex-Linked Genes • Because the X and Y chromosomes determine sex, genes located here are said to be sex-linked genes • More than 100 sex-linked genetic disorders have been mapped to the X chromosome • Males have just one X chromosome. Thus, all X-linked alleles are expressed in males, even if they are recessive

  31. Sex-Linked Genes • Genes that are found on the X or Y chromosome. • More genes are found on the X chromosome than the Y

  32. Colorblindness • Three genes associated with color vision are found on the X chromosome • Males are more often colorblind because they only have one X chromosome

  33. Colorblindness Test

  34. Colorblindness • All X-linked alleles are expressed in males even if they are recessive

  35. Examples of X-linked Recessive Disorders • Hemophilia: blood-clotting disorder • Duchenne Muscular Dystrophy • Ichtyosis: scaly skin • Norrie Disease: abnormal growth of retina • Rett Syndrome: mental retardation

  36. Hemophilia

  37. Duchenne Muscular Dystrophy

  38. X-Chromosome Inactivation • Females have 2 X chromosomes and males only one. What to do? • In all female cells, one X chromosome is randomly shut off. • This causes some interesting problems if one X chromosome has a mutated gene

  39. Chromosomal Disorders • Get too many or too few copies of a chromosome • Caused by non-disjunction during meiosis • Exs. Down’s Syndrome: Trisomy 21 Turner’s Syndrome: X_ Klinefelter’s Syndrome : XXY

  40. Down’s Syndrome

  41. Turner Syndrome

  42. Kleinfelter Syndrome

  43. 14-3 Human Molecular Genetics Human DNA Analysis • Genetic tests are now available for hundreds of disorders. • This can allow prospective parents to determine if they are carrying recessive alleles for a disorder.

  44. DNA Fingerprinting • DNA is analyzed of by separating it into fragments • This reveals a series of DNA bands of various sizes • A pattern of bands is produced that can be distinguished from any other individual in the world (except for an identical twin). • DNA samples can be obtained from blood, sperm, and hair strands that have tissue at their base.

More Related