Sources of Genetic Variation
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Transcript of Sources of Genetic Variation
![Page 1: Sources of Genetic Variation](https://reader034.fdocuments.net/reader034/viewer/2022051317/56814759550346895db49884/html5/thumbnails/1.jpg)
Sources of Genetic Variation
![Page 2: Sources of Genetic Variation](https://reader034.fdocuments.net/reader034/viewer/2022051317/56814759550346895db49884/html5/thumbnails/2.jpg)
How does Meiosis lead to genetic variation?
![Page 3: Sources of Genetic Variation](https://reader034.fdocuments.net/reader034/viewer/2022051317/56814759550346895db49884/html5/thumbnails/3.jpg)
What is Crossing Over?
• Crossing over is when homologous chromosomes EXCHANGE genetic information to create genetic DIFFERENCES!
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When does it happen?
• ONLY during MEIOSIS!
![Page 5: Sources of Genetic Variation](https://reader034.fdocuments.net/reader034/viewer/2022051317/56814759550346895db49884/html5/thumbnails/5.jpg)
What does it mean?
• It means that one person can NEVER make the same EGG or SPERM cell!
![Page 6: Sources of Genetic Variation](https://reader034.fdocuments.net/reader034/viewer/2022051317/56814759550346895db49884/html5/thumbnails/6.jpg)
What does it look like?
![Page 7: Sources of Genetic Variation](https://reader034.fdocuments.net/reader034/viewer/2022051317/56814759550346895db49884/html5/thumbnails/7.jpg)
Video Clip
• http://www.youtube.com/watch?v=5x_Rp1mwotQ
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What is Random (Independent) Assortment of Chromosomes?
• Random assortment of chromosomes means that it is completely RANDOM which CHROMOSOMES go into which gametes.
![Page 9: Sources of Genetic Variation](https://reader034.fdocuments.net/reader034/viewer/2022051317/56814759550346895db49884/html5/thumbnails/9.jpg)
When does it happen?
• ONLY during MEIOSIS!
![Page 10: Sources of Genetic Variation](https://reader034.fdocuments.net/reader034/viewer/2022051317/56814759550346895db49884/html5/thumbnails/10.jpg)
What does it mean?
• All gametes are genetically DIFFERENT!
![Page 11: Sources of Genetic Variation](https://reader034.fdocuments.net/reader034/viewer/2022051317/56814759550346895db49884/html5/thumbnails/11.jpg)
What does it look like?
![Page 12: Sources of Genetic Variation](https://reader034.fdocuments.net/reader034/viewer/2022051317/56814759550346895db49884/html5/thumbnails/12.jpg)
Video Clip
• http://www.youtube.com/watch?v=PQSvDL0SurE
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What are Mutations?
• A Mutations is when there is a MISTAKE in the DNA sequence.
![Page 14: Sources of Genetic Variation](https://reader034.fdocuments.net/reader034/viewer/2022051317/56814759550346895db49884/html5/thumbnails/14.jpg)
What can it be?
• Mutations can be BAD, GOOD or NEUTRAL!
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What happens in a BODY cell?
• The mutations will ONLY affect that PERSON
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What happens in a SEX cell?
• The mutation can be passed onto the offspring!
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What does it look like?
![Page 18: Sources of Genetic Variation](https://reader034.fdocuments.net/reader034/viewer/2022051317/56814759550346895db49884/html5/thumbnails/18.jpg)
What is Non-Disjunction of chromosomes?
• Non-Disjunction is when chromosomes FAIL to separate from each other
![Page 19: Sources of Genetic Variation](https://reader034.fdocuments.net/reader034/viewer/2022051317/56814759550346895db49884/html5/thumbnails/19.jpg)
When does it happen?
• During MEIOSIS!
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What does it result in?
• It results in the WRONG number of CHROMOSOMES in each cell.
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What are two famous examples?
1. Down Syndrome– 3 chromosomes at # 21
2. Klinefelters Syndrome– an extra X chromosome (XXY instead of XY)
![Page 22: Sources of Genetic Variation](https://reader034.fdocuments.net/reader034/viewer/2022051317/56814759550346895db49884/html5/thumbnails/22.jpg)
What does it look like?
![Page 23: Sources of Genetic Variation](https://reader034.fdocuments.net/reader034/viewer/2022051317/56814759550346895db49884/html5/thumbnails/23.jpg)
Video Clip
• http://www.youtube.com/watch?v=_aIWe8Ydm-Q
• http://www.youtube.com/watch?v=EA0qxhR2oOk&feature=related
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What is fertilization?
• Fertilization is when an EGG and SPERM come together.
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What does it create?
• They create 100% UNIQUE combination of genes!
![Page 26: Sources of Genetic Variation](https://reader034.fdocuments.net/reader034/viewer/2022051317/56814759550346895db49884/html5/thumbnails/26.jpg)
What does it look like?
![Page 27: Sources of Genetic Variation](https://reader034.fdocuments.net/reader034/viewer/2022051317/56814759550346895db49884/html5/thumbnails/27.jpg)
Video Clip
• http://www.youtube.com/watch?v=9MnQxiSJZ4Q
![Page 28: Sources of Genetic Variation](https://reader034.fdocuments.net/reader034/viewer/2022051317/56814759550346895db49884/html5/thumbnails/28.jpg)
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