Download Chapter 7 Extending Mendelian Genetics

Extending Mendelian Genetics
Chapter 7
Mr. Scott
Human Heredity
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Human body
• 46 chromosomes
 ____________________ sperm cell with 23 chromosomes
 Haploid egg cell with 23 chromosomes
 They form a diploid zygote or fertilized egg cell with 46 chromosomes
Human Heredity
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• 2 of the 46 chromosomes
• Determine the sex of that person
Females have X and X or XX chromosomes
 Males have X and Y or XY chromosomes
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Human Heredity
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• The other 44 chromosomes found in all body cells
• These are the chromosomes separate from the sex cells
• Typically numbered on a _________________________
 Human traits
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Pedigree chart –
• Shows how traits may be passed through generations
 Human genes
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Human Heredity
Human Heredity
Blood group genes
• Rh blood groups
 Positive and negative
 Rh+ is dominant
• ABO blood groups
 IA, I B, and i
 IA and I B are codominant
Human Heredity
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Recessive alleles
• Genetic disorders usually are not discovered until
___________________________________________
Dominant alleles
• Anyone ___________________________________ will have the
disorder
Codominant alleles
 From gene to molecule
Human Heredity
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• Common in people from northern Europe
• Serious digestive and breathing problems
• Caused by the _________________________________________
Human Heredity
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• Blood cells doughnut or comma shaped
• Heterozygous people don’t contract malaria
• Humans with all sickle celled blood can die
• Why do so many African Americans have sickle celled blood?
Human Chromosomes
 Human genes and chromosomes
 One cell has __________________________________ or A,C,T,& G
 46 Chromosomes are found in every diploid human cell
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Human Chromosomes
Only ___________________________ of all DNA is used for genes or
transcribed into RNA
Average genes are 3,000 base pairs
Largest gene is _____________________________________________
Human Chromosomes
Chromosomes __________________________________ are the smallest
• 22 has 545 genes (43 million base pairs)
• 21 has 225 genes (21 million base pairs)
 Lou Gehrig’s Disease or Amyotrophic Lateral Sclerosis(ALS)
 Sex-linked genes –
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Human Chromosomes
Colorblindness
• Red-green colorblindness
 1 in 10 males
 1 in 100 females
 W hy do more males have colorblindness?
Human Chromosomes
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• Blood does not clot properly
• Is determined by two genes on the X-chromosome
• 1 in 10,000 males
• Ryan White
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Human Chromosomes
Duchenne Muscular Dystrophy
•
• 1 in 3,000 males
• Caused by a defective gene that codes for a protein in muscles
Human Chromosomes
 X-chromosome inactivation
 __________________________ – dense area in a nucleus where the
inactivated X chromosome is located
 Each cell controls which X chromosome is turned off
• Calico cat
 Chromosomal Disorders
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Human Chromosomes
Nondisjunction –
Human Chromosomes
Down syndrome
• Caused by ____________________________ of chromosome
21(Trisomy 21)
• 1 in 800 babies
• This is a nondisjunction condition
Human Chromosomes
 Sex chromosome disorders
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• Females (45,X)
• Sterile
• No sex organs
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• Males (47, XXY)
• Sterile
 Gene linkage
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Linkage and Gene Maps
Chromosomes assort independently, not individual genes
Linkage and Gene Maps
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Shows the exact location of each known gene on one chromosome
 Human DNA analysis
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Human Molecular Genetics
Search the human genome using sequences of DNA bases
Human Molecular Genetics
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• No two humans are exactly alike
• Analyze and compare low function DNA segments
Human Molecular Genetics
 The Human Genome Project
 An ongoing effort to analyze the ___________________________
 Finished in 2000
Human Molecular Genetics
 A breakthrough for everyone
• Public access to Human genome project
Human Molecular Genetics

Changing the gene that causes a genetic disorder
• Use ________________________ to infect cells with good gene
• 1999 - First person cured of genetic disorder
Human Heredity
 Human chromosomes
 Karyotype –
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Human Heredity
Human Molecular Genetics
 Ethical issues in human genetics
 Should we use genetics to make people better?