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Aim: How do your genetics play a role in the person you are today?

Aim: How do your genetics play a role in the person you are today?. Do Now: What similarities do you have with your parents or siblings? Homework:Textbook 126-132 #1-5 . Human Genetics. What is Heredity?. The transfer of characteristics from one generation to the next. What are Traits?.

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Aim: How do your genetics play a role in the person you are today?

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  1. Aim: How do your genetics play a role in the person you are today? • Do Now: What similarities do you have with your parents or siblings? • Homework:Textbook 126-132 #1-5

  2. Human Genetics

  3. What is Heredity? • The transfer of characteristics from one generation to the next

  4. What are Traits? • A characteristic that is determined by your genes • A pair of genes will determine the trait • Examples: • Tongue rolling • Earlobes • Widow’s Peak • Hair Whorl • Dimples

  5. What is genetics? • The science of how traits are inherited

  6. Where do our genes come from? • We had said that a pair of genes determines which traits we will inherit from our parents • Why would it be a pair of genes? • Each parent provides a sex cell in order for fertilization to occur • The father will provide a sperm cell that has 23 chromosomes • The mother will provide an egg cell that has 23 chromosomes • When these two cells merge and become one, fertilization has occurred, and as a result, the new fertilized egg has 46 chromosomes (23 + 23 = 46)

  7. + 23 chromosomes 23 chromosomes 46 chromosomes

  8. How are traits determined? • Dominant Genes – the traits that will usually appear in the individual (represented by an uppercase letter) • If an organism has a gene for blue or brown eyes, usually it will have brown eyes because in is the dominant gene • Recessive Genes – The gene hidden by the dominant gene (represented by a lowercase letter) • Blue-eyed people need two recessive genes to show the blue-eyed trait

  9. Who is Gregor Mendel? • “Father of Genetics” • Studied pea plants • He crossed pea plants with different characteristics and studied their offspring • He was able to determine how traits get passed on from generation to generation

  10. What is a Punnett Square? • A table that shows the possible results when the genes of two parents are crossed • It shows the probability of a trait to be expressed in the offspring B – Brown Eyes b – Blue Eyes

  11. What is a genotype? • The genetic code or make up of the individual • Examples: BB, Bb, bb

  12. What is a genotype? • Homozygous dominant – a pair of dominant genes (BB) • Homozygous recessive – a pair of recessive genes (bb) • Heterozygous or hybrid – a mixed pair of one dominant gene and one recessive gene (Bb)

  13. What is a phenotype? • The way an organism looks or behaves • Examples:

  14. Examples: BB x bb Bb x bb Bb x Bb bb x bb BB x BB BB x Bb B = Brown Eyes b = Blue Eyes What we are looking for: Genotypes Phenotypes Percentage Brown eyes Percentage Blue Eyes Lets try some Punnett Squares!

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