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Pedigree Questions: 1. A circle represents a ________________ 2. A square represents a _____________ 3. A ___________ line connects a circle and square. 4. What are the roman numerals for? 5. Half shaded means an individual is a ___________ 6. Fully shaded means an individual is ____________
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1. List all the Blood Phenotypes and their Blood Genotypes. 2. Cross Heterozygous A with Homozygous B 3. Cross O with Heterozygous B 4. Cross AB with Homozygous A !Determine G. Possibilities and G. Ratios! !Determine P. Possibilities and P. Ratios!
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Mutations and Nondisjunction
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Joke of the Day:
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Mutations and Nondisjunction
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" Mutation. It is the key to our evolution. It has enabled us to evolve from a single-celled organism into the dominant species on the planet."
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The Human Genome: Facts Genome: Complete set of DNA/Genetic Material In every Cell: 46 Chromosomes or 23 Homologous pairs. Pairs #1-22: Autosomes - Pair #23: Sex Chromosomes – X and Y (Gender) Normal Male: 46XY Normal Female: 46XX 3.3 Billion Nucleotides 30,000 Genes (estimated)
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Photograph of a full set of chromosomes in ordered pairs. (microscope) Usually look at chromosomes in white blood cells Identify chromosomal alterations that may result in a genetic disorder.
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Normal Female Normal Male
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Mutation: Changes in the DNA sequence that affect genetic code. The ultimate source of genetic variability in a population. Most Mutations are neutral
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If a mutation occurs during the formation of gametes, it may be passed to the offspring. If a mutation occurs later in life inside a body cell, the mutation is not inherited.
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Gene Mutation : a change in a single gene Mutation Example: Point Mutation - One nucleotide (letter) in the DNA is changed. Disorder Example: Tay Sach’s Disease – Lipid accumulation in brain
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Chromosome Mutation: change in the whole chromosome. Mutation Example: Deletion, Duplication, Inversion, or Translocation Disorder Example: Fragile X – Severe learning disabilities
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During Meiosis, the homologous chromosomes fail to separate properly Causes an abnormal number of chromosomes in the gametes and may lead to disorders.
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Homologous chromosomes fail to separate Meiosis I: Nondisjunction Meiosis II
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Trisomy 21: Down’s Syndrome Occurs when there is an extra copy of chromosome 21. This causes problems with the way the body and brain develop. Causes mild to severe mental retardation. 1 in 800 babies in the US is born with Down’s Syndrome.
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Turner’s Syndrome: A problem in females where she only inherits one X chromosome.. The woman is sterile. Kleinfelter’s Syndrome: A problem in males where he inherits an extra X chromosome. The man is sterile. (47XXY Kleinfelter’s). (45XO Turner’s)
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Kleinfelter’s SyndromeTurner’s Syndrome Turner’s Syndrome 45XO
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Jacob’s Syndrome: Genetic condition in which a human male has an extra male (Y) chromosome,. (47,XYY) Occurs in 1 in 1,000 male births. Increased average height Delayed puberty Learning difficulties Speech problems
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