1. How is variation produced in
a population?
Jennifer Oh (SL)
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2. What is genetic variation?
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3. What is genetic variation?
Variation in alleles of
genes
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4. What is genetic variation?
Variation in alleles of
genes
Occurs within and
among populations
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5. What is genetic variation?
Variation in alleles of
genes
Occurs within and
among populations
The “raw material” of
natural selection
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6. Sources of Genetic Variation
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7. Sources of Genetic Variation
Mutations
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8. Sources of Genetic Variation
Mutations
Gene mutations
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9. Sources of Genetic Variation
Mutations
Gene mutations
Chromosome
mutations
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10. Sources of Genetic Variation
Mutations
Gene mutations
Chromosome
mutations
Sexual Reproduction
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11. Sources of Genetic Variation
Mutations
Gene mutations
Chromosome
mutations
Sexual Reproduction
Recombination
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12. Sources of Genetic Variation
Mutations
Gene mutations
Chromosome
mutations
Sexual Reproduction
Recombination
Mate selection
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13. Assessment Statements
These are the assessment statements that
deal with this topic:
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14. Assessment Statements
These are the assessment statements that
deal with this topic:
4.1.2 Define gene, allele, and genome
4.1.3 Define gene mutation
State that meiosis is a reduction division of a diploid nucleus
4.2.1 to form haploid nuclei
Outline the process of meiosis, including pairing of
4.2.3 homologous chromosomes and crossing over, followed by t wo
divisions, which results in four haploid cells
Define genotype, phenotype, dominant allele, recessive allele,
4.3.1 codominant alleles, locus, homozygous, heterozygous, carrier
and test cross
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15. Basic Vocabulary
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16. Basic Vocabulary
Before diving into the details of genetic
variation, here are some basic terms that you
need to know for this topic.
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17. Basic Vocabulary
Before diving into the details of genetic
variation, here are some basic terms that you
need to know for this topic.
From assessment statement 4.1.2
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18. Basic Vocabulary
Before diving into the details of genetic
variation, here are some basic terms that you
need to know for this topic.
From assessment statement 4.1.2
Gene, Allele, Genome
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19. Basic Vocabulary
Before diving into the details of genetic
variation, here are some basic terms that you
need to know for this topic.
From assessment statement 4.1.2
Gene, Allele, Genome
From assessment statement 4.3.1
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20. Basic Vocabulary
Before diving into the details of genetic
variation, here are some basic terms that you
need to know for this topic.
From assessment statement 4.1.2
Gene, Allele, Genome
From assessment statement 4.3.1
Genotype, phenotype
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21. 4.1.2 Vocab
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22. 4.1.2 Vocab
Gene - a heritable factor that controls a
specific characteristic
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23. 4.1.2 Vocab
Gene - a heritable factor that controls a
specific characteristic
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24. 4.1.2 Vocab
Gene - a heritable factor that controls a
specific characteristic
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25. 4.1.2 Vocab
Gene - a heritable factor that controls a
specific characteristic
Allele - one specific form of a gene, differing
from other alleles by one or a few bases only
and occupying the same gene locus as other
alleles of the gene
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26. 4.1.2 Vocab
Gene - a heritable factor that controls a
specific characteristic
Allele - one specific form of a gene, differing
from other alleles by one or a few bases only
and occupying the same gene locus as other
alleles of the gene
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27. 4.1.2 Vocab
Gene - a heritable factor that controls a
specific characteristic
Allele - one specific form of a gene, differing
from other alleles by one or a few bases only
and occupying the same gene locus as other
alleles of the gene
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28. 4.1.2 Vocab
Gene - a heritable factor that controls a
specific characteristic
Allele - one specific form of a gene, differing
from other alleles by one or a few bases only
and occupying the same gene locus as other
alleles of the gene
Genome - the whole genetic information of
an organism
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29. 4.3.1 Vocab
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30. 4.3.1 Vocab
Genotype - the alleles of an organism;
determines the genetic potential
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31. 4.3.1 Vocab
Genotype - the alleles of an organism;
determines the genetic potential
Phenotype - the characteristics of an
organism
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32. Mutation
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33. Mutation
Mutations are the source of all new genetic information
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34. Mutation
Mutations are the source of all new genetic information
Not always harmful, some are neutral or beneficial
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35. Mutation
Mutations are the source of all new genetic information
Not always harmful, some are neutral or beneficial
Can be accumulated over many generations
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36. Mutation
Mutations are the source of all new genetic information
Not always harmful, some are neutral or beneficial
Can be accumulated over many generations
Gene mutation (4.1.3)
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37. Mutation
Mutations are the source of all new genetic information
Not always harmful, some are neutral or beneficial
Can be accumulated over many generations
Gene mutation (4.1.3)
Change in the base sequence of an allele
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38. Mutation
Mutations are the source of all new genetic information
Not always harmful, some are neutral or beneficial
Can be accumulated over many generations
Gene mutation (4.1.3)
Change in the base sequence of an allele
Chromosome mutation
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39. Mutation
Mutations are the source of all new genetic information
Not always harmful, some are neutral or beneficial
Can be accumulated over many generations
Gene mutation (4.1.3)
Change in the base sequence of an allele
Chromosome mutation
Pieces of chromosomes may be rearranged during
meiosis
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40. Mutation
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41. Sexual Reproduction
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42. Sexual Reproduction
Provides rearrangement and shuffling of the genetic
material into new combinations
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43. Sexual Reproduction
Provides rearrangement and shuffling of the genetic
material into new combinations
Crossing over - Recombination
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44. Sexual Reproduction
Provides rearrangement and shuffling of the genetic
material into new combinations
Crossing over - Recombination
Pieces of chromosome are often exchanged with a
chromosome’s homologue
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45. Sexual Reproduction
Provides rearrangement and shuffling of the genetic
material into new combinations
Crossing over - Recombination
Pieces of chromosome are often exchanged with a
chromosome’s homologue
Increases shuffling of allele combinations
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46. Sexual Reproduction
Provides rearrangement and shuffling of the genetic
material into new combinations
Crossing over - Recombination
Pieces of chromosome are often exchanged with a
chromosome’s homologue
Increases shuffling of allele combinations
Mate Selection
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47. Sexual Reproduction
Provides rearrangement and shuffling of the genetic
material into new combinations
Crossing over - Recombination
Pieces of chromosome are often exchanged with a
chromosome’s homologue
Increases shuffling of allele combinations
Mate Selection
Different combinations of genes will come together
in the offspring depending on which t wo parents
mate together
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48. Meiosis
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49. Meiosis
Meiosis is a reduction division of a diploid nucleus to form
haploid nuclei (4.2.1)
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50. Meiosis
Meiosis is a reduction division of a diploid nucleus to form
haploid nuclei (4.2.1)
For this topic, the important part is: crossing over
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51. Meiosis
Meiosis is a reduction division of a diploid nucleus to form
haploid nuclei (4.2.1)
For this topic, the important part is: crossing over
At Prophase I, the homologous chromosomes pair up
(synapsis), and segments of the chromosome can be
exchanged
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52. Meiosis
Meiosis is a reduction division of a diploid nucleus to form
haploid nuclei (4.2.1)
For this topic, the important part is: crossing over
At Prophase I, the homologous chromosomes pair up
(synapsis), and segments of the chromosome can be
exchanged
Important source of variation for the gene pool of a
population
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53. Watch this video!
GREAT video lesson about genetic variation:
http://www.khanacademy.org/video/
variation-in-a-species?playlist=Biology
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54. i-Biology Link
4.1 Presentation
http://i-biology.net/?s=4.1
4.2 Presentation
http://i-biology.net/?s=4.2
4.3 Presentation
http://i-biology.net/?s=4.3
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55. More exercises
For more exercises on this topic, look at these
pages from the Biozone workbook.
Mutations: p. 197 - 8
Meiosis: p. 185 - 8
Genetic Variation: p. 181 - 2
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56. The End!
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