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What exactly are Chromosomes, DNA and Genes?

What exactly are Chromosomes, DNA and Genes?. Introduction to Genetics. Introduction to Genetics Video. Chromosome. 46 inside every cell Chromosomes are in the cell in pairs. One came from mom and one came from dad . . Dad’s Chromosome. Mom’s Chromosome.

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What exactly are Chromosomes, DNA and Genes?

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  1. What exactly are Chromosomes, DNA and Genes? Introduction to Genetics

  2. Introduction to Genetics Video

  3. Chromosome • 46 inside every cell • Chromosomes are in the cell in pairs. • One came from mom and one came from dad. Dad’s Chromosome Mom’s Chromosome

  4. DNA - deoxyribonucleic (say: dee-ox-see-ri-bo-nyoo-clay-ik) acid • Long strands of genetic code • Makes up chromosomes in plants and animals DNA

  5. Genes • Tiny pieces of DNA that are instructions for specific traits

  6. Traits • Things that you inherit from your parents • Examples: Hair color, eye color and having freckles or not • Through sexual reproduction you inherited a set of traits

  7. Traits • Pairs of letters are used to define genes in your body • CAPTIAL LETTERS are used to represent DOMINANT genes • lower case letters are used to represent recessive genes • Dominant trait: If you receive even one of these in the pair, you will get a specific trait. • Recessive trait: You have to have two of these in the pair to get a specific trait

  8. Genotypes • The letter associated with the gene • Example: W (dominant widow’s peak) w (recessive no widow’s peak)

  9. Phenotypes • This is the "outward, physical manifestation“ • The actual physical trait • Example: Widows Peak

  10. Allele • Allele: The single letter such as the a or the A.

  11. Heterozygous – having two different alleles • Aa • Bb

  12. Homozygous – having the same alleles • AA • BB

  13. Practice: B – brown hair b – red hair My genes: Bb What color hair will I have? Is Bb the phenotype or the genotype? Are my genes heterozygous or homozygous?

  14. Practice: A – attached earlobe a – unattached earlobe My genes: aa What will my earlobes do? Is attached earlobe the phenotype or the genotype? Is my genotype homozygous or heterozygous?

  15. Practice: D – dimples d – no dimples My genes: DD Do I have dimples or not? What is the genotype? Is my genotype heterozygous or homozygous?

  16. Quiz F – freckles f – no freckles My genes: FF Do I have freckles or not? What is the phenotype? What is the genotype? Is my genotype heterozygous or homozygous? Which parent carried the dominant gene?

  17. What is a PUNNETT SQUARE? • A tool to predict the probability of certain traits in offspring that shows the different ways alleles can combine • A way to show phenotype & genotype • A chart that shows all the possible combinations of alleles that can result when genes are crossed

  18. Punnett Squares Video

  19. Using a PUNNETT SQUARE To set up a Punnett square, draw a large square, and then divide it into 4 equal sections (also squares). It should look something like this:

  20. Using a PUNNETT SQUARE • Now you need two parents to mate, ones with a known genotype • For example, Brown hair (genotype BB) and blonde hair (genotype Bb). BB x Bb • In this scenario, the Mom has brown hair. The dad blonde hair.

  21. Using a PUNNETT SQUARE • The two-letter combinations are the possible genotypes of offspring • They are: BB, Bb, BB, and Bb genotypes • From this it is possible to determine the probability (chance) that a baby will have a brown phenotype (2/4 or 50%) or a blonde phenotype (2/4 or 50%)

  22. Using a PUNNETT SQUARE Place one of the parents on top, and one on the left. You should get a something similar to this: B b B 100% B What is the probability of having the recessive trait?

  23. Punnet Square Practice with White Boards 100% h h H H What is the probability of having the dominant trait?

  24. Punnet Square Practice with White Boards 25% w W w W What is the probability of having the recessive trait?

  25. Punnet Square Practice with White Boards 50% w W w w What is the probability of having the dominant trait?

  26. Does it work with animals and plants? • Yes, all of this works the same way in determining the outcome of combining animals and plants. • How can we relate this to selective breeding? • How can we relate this to genetic engineering?

  27. Pedigree Charts • http://www.youtube.com/watch?feature=player_embedded&v=Wuk0W10EveU

  28. Extracting DNA from a Banana Lab Expectations: • C.H.A.M.P.S. Group Work • Conversation: Voice Level 1-2 • Help: 3 Fingers Signal • Activity: Complete Lab and Activity Sheet • Movement: Stay in Seats, Use Finger Signals • Participation: Discuss, Help with Lab, Group Jobs

  29. DNA Extraction Virtual Lab • http://learn.genetics.utah.edu/content/labs/extraction/#

  30. Example Video • http://www.youtube.com/watch?v=dhS89DfP-aQ

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