Evolution: Genetics Mr. Kasteler Zoology Day 22
The Standards: <ul><li>SC.912.L.15.15 Describe how mutation and genetic recombination increase genetic variation  </li></u...
Basic Genetics <ul><li>Brief review:  </li></ul><ul><ul><li>What is DNA? </li></ul></ul><ul><ul><li>How many nucleotide ba...
Some more important definitions: <ul><li>GENOTYPE : the actual GENES (technically, ALLELES) an organism has </li></ul><ul>...
A few definitions you just gotta know… <ul><li>A  GENE  is a location on your DNA  that codes for a physical trait (i.e. h...
Basic Inheritance <ul><li>What’s inheritance? </li></ul><ul><li>Let’s talk about basic inheritance patterns </li></ul><ul>...
These are chromosomes…
How many chromosomes do you have? <ul><li>how many do you have? </li></ul><ul><li>46! … How many from Dad? From Mom? </li>...
Mendel’s Peas: <ul><li>The brief synopsis: Gregor Mendel (the Father of Genetics) did experiments on pea plants.  Some of ...
Punnett Squares <ul><li>Hopefully, we’ve all dealt with punnett squares in previous biology classes… but if not…here’s a q...
Punnett Square Set Up <ul><li>You put the trait alleles of one parent across the top, and the trait alleles of the other p...
The Basics: Gender Alleles
<ul><li>What is the likelihood that this couple will have a boy?  A girl?  </li></ul>
A little reminder of  where you came from… <ul><li>So, we get half of our genome from Mom, and half of our genome from Dad...
Genetic Variation <ul><li>Just as biodiversity increases the stability of an ecosystem,  greater genetic variation improve...
DIFFERENT is GOOD <ul><li>When two individuals with similar genomes mate, they have a higher likelihood of passing down a ...
Ways to vary the Gene Pool <ul><li>Genetic Mutations  </li></ul><ul><li>Genetic Recombination </li></ul><ul><li>Gene Flow ...
Genetic Mutations <ul><li>There are two main types of genetic mutations you need to know: </li></ul><ul><li>Point Mutation...
Point Mutation <ul><li>This is where a single base pair is changed </li></ul><ul><li>Example: The dog bit the cat </li></u...
Frame Shift Mutations <ul><li>An  insertion  occurs when a base pair is  inserted  into the genome, shifting the genetic r...
Frame Shift Mutations <ul><li>A  deletion  occurs when a base pair is  deleted  from the genome, also shifting the genetic...
Let’s Discuss… <ul><li>What is worse- a deletion or an insertion? Why? </li></ul><ul><ul><li>Answer: Deletion </li></ul></ul>
Genetic Recombination <ul><li>This occurs during  meiosis </li></ul><ul><ul><li>Meiosis: formation of sex cells  </li></ul...
Genetic Recombination <ul><li>The gamete genotypes went from aa AA… (homozygous)  </li></ul><ul><li>… to aA aA </li></ul><...
<ul><li>X  = </li></ul>
Gene Flow <ul><li>Genes flow into the gene pool when new individuals are added to the population through  IMM IGRATION </l...
Genetic Drift <ul><li>Think: CHANCE </li></ul><ul><li>Genetic Drift occurs when the allelic frequency within a population ...
Genetic Drift <ul><li>Example: If I flip a coin 10,000 times, how many times would I get heads? Tails?  </li></ul><ul><li>...
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11 1-11 genetics

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11 1-11 genetics

  1. 1. Evolution: Genetics Mr. Kasteler Zoology Day 22
  2. 2. The Standards: <ul><li>SC.912.L.15.15 Describe how mutation and genetic recombination increase genetic variation </li></ul><ul><li>SC.912.L.15.14 Discuss mechanisms of evolutionary change other than natural selection such as genetic drift and gene flow </li></ul>
  3. 3. Basic Genetics <ul><li>Brief review: </li></ul><ul><ul><li>What is DNA? </li></ul></ul><ul><ul><li>How many nucleotide bases are there? </li></ul></ul><ul><ul><li>Which ones pair together? </li></ul></ul>
  4. 4. Some more important definitions: <ul><li>GENOTYPE : the actual GENES (technically, ALLELES) an organism has </li></ul><ul><li>PHENOTYPE : the PHYSICAL CHARACTERISTIC exhibited by the organism </li></ul><ul><li>HOMO ZYGOUS : when an organism has two identical (the SAME ) alleles </li></ul><ul><li>HETERO ZYGOUS : when an organism has two different alleles </li></ul><ul><li>Dominant & Recessive… </li></ul><ul><li>Ex. Mendel’s Peas… </li></ul>
  5. 5. A few definitions you just gotta know… <ul><li>A GENE is a location on your DNA that codes for a physical trait (i.e. height, hair color, eye color) </li></ul><ul><li>An ALLELE is a form of a gene coding for a given trait (i.e. tall, short, blonde, brunette, blue eyed, brown eyed, etc.) </li></ul>
  6. 6. Basic Inheritance <ul><li>What’s inheritance? </li></ul><ul><li>Let’s talk about basic inheritance patterns </li></ul><ul><li>Animals have varying numbers of chromosomes… </li></ul><ul><li>Background CFU: What’s a chromosome? </li></ul><ul><ul><li>A chromosome is bundled up DNA </li></ul></ul>
  7. 7. These are chromosomes…
  8. 8. How many chromosomes do you have? <ul><li>how many do you have? </li></ul><ul><li>46! … How many from Dad? From Mom? </li></ul><ul><li>What’s the genotype for a female? Male? </li></ul>
  9. 9. Mendel’s Peas: <ul><li>The brief synopsis: Gregor Mendel (the Father of Genetics) did experiments on pea plants. Some of them were tall (Is this a genotype or phenotype?) and some of them were short (Is this a genotype or phenotype?). He found that some of his tall plants were TT while others were Tt, with T coding for Tall and t coding for short (Is this a genotype or phenotype?). All of his short pea plants were tt (Is this a genotype or phenotype?) He crossed plants with different genotypes to see what kinds of phenotypes the offspring would exhibit. He developed Punnett squares. </li></ul>
  10. 10. Punnett Squares <ul><li>Hopefully, we’ve all dealt with punnett squares in previous biology classes… but if not…here’s a quick reminder of how you set them up. </li></ul>
  11. 11. Punnett Square Set Up <ul><li>You put the trait alleles of one parent across the top, and the trait alleles of the other parent down the side. </li></ul><ul><ul><li>An allele is a gene coding for a given trait (i.e. tall, short, blonde, brunette, blue eyed, brown eyed, etc.) </li></ul></ul><ul><li>This can get tricky with complicated variable genetic traits, such as eye color </li></ul>
  12. 12. The Basics: Gender Alleles
  13. 13. <ul><li>What is the likelihood that this couple will have a boy? A girl? </li></ul>
  14. 14. A little reminder of where you came from… <ul><li>So, we get half of our genome from Mom, and half of our genome from Dad. </li></ul><ul><li>How much of your Dad’s genome will your children get? </li></ul><ul><ul><li>This will help us determine relatedness for the next unit on animal behavior </li></ul></ul>
  15. 15. Genetic Variation <ul><li>Just as biodiversity increases the stability of an ecosystem, greater genetic variation improves the genetic stability of a population </li></ul><ul><ul><li>More potential alleles means a higher likelihood that one or more individuals carry genes that could adapt to a new environment </li></ul></ul><ul><ul><li>When a population becomes too homogeneous , they are susceptible to genetic disorders and disease </li></ul></ul><ul><ul><li>Think… this is why it’s not a good idea to marry your brother or sister… or cousin </li></ul></ul>
  16. 16. DIFFERENT is GOOD <ul><li>When two individuals with similar genomes mate, they have a higher likelihood of passing down a recessive, deleterious (harmful) trait and having that trait expressed in the offspring </li></ul>
  17. 17. Ways to vary the Gene Pool <ul><li>Genetic Mutations </li></ul><ul><li>Genetic Recombination </li></ul><ul><li>Gene Flow (Immigration & Emigration) </li></ul><ul><li>Genetic Drift </li></ul>
  18. 18. Genetic Mutations <ul><li>There are two main types of genetic mutations you need to know: </li></ul><ul><li>Point Mutation </li></ul><ul><li>Frame Shift Mutation </li></ul><ul><ul><li>Insertion </li></ul></ul><ul><ul><li>Deletion </li></ul></ul>
  19. 19. Point Mutation <ul><li>This is where a single base pair is changed </li></ul><ul><li>Example: The dog bit the cat </li></ul><ul><li>Point Mutation: The dog bit the ca r </li></ul><ul><li>NOTICE: The severity of the mutation depends on the exact place of the change, not necessarily whether the mutation occurs earlier or later in the gene </li></ul><ul><li>It’s like a schedule change that just swaps one class for another, same period </li></ul>
  20. 20. Frame Shift Mutations <ul><li>An insertion occurs when a base pair is inserted into the genome, shifting the genetic reading frame </li></ul><ul><ul><li>Example: The dog mbi tth eca t </li></ul></ul><ul><ul><li>*Notice: The gene is fine upstream (before) of the mutation </li></ul></ul><ul><li>It’s like a schedule change that alters one class… and messes up your whole schedule </li></ul>
  21. 21. Frame Shift Mutations <ul><li>A deletion occurs when a base pair is deleted from the genome, also shifting the genetic reading frame </li></ul><ul><ul><li>Example: The dob itt hec at </li></ul></ul><ul><ul><li>*Notice: Again, the gene is fine upstream of the mutation </li></ul></ul><ul><li>What do you think is more serious, a mutation in the earlier part of the gene or later on? Why? </li></ul>
  22. 22. Let’s Discuss… <ul><li>What is worse- a deletion or an insertion? Why? </li></ul><ul><ul><li>Answer: Deletion </li></ul></ul>
  23. 23. Genetic Recombination <ul><li>This occurs during meiosis </li></ul><ul><ul><li>Meiosis: formation of sex cells </li></ul></ul><ul><li>Recombination/Crossing Over is when two gametes exchange pieces of genetic information </li></ul>
  24. 24. Genetic Recombination <ul><li>The gamete genotypes went from aa AA… (homozygous) </li></ul><ul><li>… to aA aA </li></ul><ul><li>(heterozygous) </li></ul>
  25. 25. <ul><li>X = </li></ul>
  26. 26. Gene Flow <ul><li>Genes flow into the gene pool when new individuals are added to the population through IMM IGRATION </li></ul><ul><ul><li>INCREASES GENETIC VARIATION </li></ul></ul><ul><li>Genes flow out of the gene pool when individuals leave the population through EM IGRATION </li></ul><ul><ul><li>DECREASES GENETIC VARIATION </li></ul></ul>
  27. 27. Genetic Drift <ul><li>Think: CHANCE </li></ul><ul><li>Genetic Drift occurs when the allelic frequency within a population changes due to chance sampling from the gene pool </li></ul><ul><ul><li>It is particularly potent in SMALL populations </li></ul></ul>
  28. 28. Genetic Drift <ul><li>Example: If I flip a coin 10,000 times, how many times would I get heads? Tails? </li></ul><ul><li>If I flip the same coin 10 times, how many times will I get heads? Tails? </li></ul><ul><li>Which example has a higher likelihood of being wrong (especially in percent)? </li></ul><ul><li>**FOUNDER EFFECT & Islands** </li></ul><ul><li>**Bottleneck Effect** </li></ul>

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